Dissertations / Theses: 'Modes of reproduction'

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Schneider, Maria Victoria. "Modes de reproduction chez le parasitoi͏̈de solitaire Venturia canesces." Lyon 1, 2003. http://www.theses.fr/2003LYO10071.

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Venturia canescens, un parasitoi͏̈de ichneumonidé de chenilles de piralidés, a deux modes de reproduction : arrhénotoque, (mâles haploi͏̈des et femelles diploi͏̈des)) et thélytoque (des femelles vierges engendrent des filles diploi͏̈des). Cette thélytoquie n'est pas l'effet de bactéries symbiotiques. Dans le Sud de la France, les deux modes de reproduction coexistent en sympatrie. La thèse traite des questions soulevées par cette coexistence. Une étude de la distribution géographique et une analyse moléculaire des populations, ont montré l'existence d'un clone thélytoque très répandu. Cependant quelques individus thélytoques sont génétiquement très proches des individus arrhénotoques. Une importante partie de la variabilité chez les thélytoques est due à un flux génique à partir de mâles arrhénotoques. Pour mieux comprendre la coexistence des deux modes de reproduction, différents traits d'histoire de vie et compromis génétiques reflétants des différentes pressions de sélection ont été étudiés.

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Eyer, Pierre-André. "Modes de reproduction et diversité génétique chez les fourmis du genre Cataglyphis." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209190.

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Les insectes sociaux représentent le paradigme de la vie coopérative dans le règne animal. Ceci repose sur l’existence d’une division des activités reproductrices entre des individus reproducteurs (les reines et les mâles) et une majorité d’ouvrières sacrifiant leurs propres potentialités reproductives pour assurer l’essentiel des tâches logistiques nécessaires à l’essor des sociétés. Chez les Hyménoptères sociaux, l’analyse comparative des stratégies de reproduction révèle que la structure monogyne (une reine par société) et monandre (un seul accouplement par reine) est l’état ancestral des sociétés. Cette structure favorise une corrélation génétique élevée entre les ouvrières et le couvain qu’elles élèvent et, par conséquent, leur succès reproductif global (inclusive fitness). Cependant, un nombre croissant d’études génétiques montre que la structure des sociétés peut fortement s’éloigner de ce pattern. Ceci est particulièrement manifeste chez les fourmis, lesquelles présentent un très large polymorphisme social se traduisant par une grande variabilité du nombre de femelles reproductrices au sein des sociétés. Les formicidés sont également remarquables par la diversité de leurs modes de reproduction. Cette diversité concerne la fréquence des accouplements (monandrie/polyandrie) ou encore l’exploitation conditionnelle des modes de reproductions sexuée et asexuée. Chez quelques espèces, les futures reines sont en effet produites par parthénogenèse (elles sont des quasi-clones de leur mère), alors que les ouvrières sont issues d'une reproduction sexuée classique. Cette stratégie exceptionnelle permet aux reines d'accroître le taux de transmission de copies de leurs gènes dans la descendance, tout en conservant les bénéfices d'une diversité génétique dans la force ouvrière. Cette grande diversité de structures sociales et de modes de reproduction suggère l’action de nombreuses pressions sélectives. Les travaux réalisés dans le cadre de cette thèse de doctorat visent à déterminer les facteurs responsables du large polymorphisme social et des nombreux modes de reproduction observés chez les fourmis désertiques du genre Cataglyphis. Ils sont articulés autour de deux axes principaux.

Les analyses phylogénétiques montrent que la polyandrie est ancestrale au sein du genre Cataglyphis. Le premier axe de ce travail a pour but d’étudier les causes évolutives justifiant le maintien d’un tel système de reproduction au sein de ce genre. Ce travail porte sur les avantages d’une diversité génétique accrue parmi les ouvrières. Une telle diversité génétique permettrait notamment d'accroître le polymorphisme de taille des ouvrières et l'efficacité de la division du travail [Chapitre 1], ou la résistance aux pathogènes de la force ouvrière [Chapitre 2]. [1] Ce premier travail a été réalisé sur Cataglyphis cursor, une espèce strictement monogyne et polyandre. Les résultats de cette étude révèlent une très grande fidélité des ouvrières à la tâche. Ils montrent l’existence d’une association significative entre la tâche réalisée par une ouvrière et sa lignée paternelle, ainsi qu’entre la taille des ouvrières et la tâche effectuée. [2] Le second travail de cette thèse a été réalisé chez C. mauritanica. Nos résultats montrent que la résistance aux pathogènes diffère entre ouvrières issues de différentes lignées paternelles lorsque ces dernières sont isolées. Curieusement, cette différence s’estompe lorsque les lignées paternelles sont regroupées au sein des sociétés polyandres. Dès lors, la polyandrie permettrait d’homogénéiser l’immunité des sociétés. Nos données montrent cependant que la résistance des ouvrières à Metarhizium anisopliae n’est pas corrélée à la diversité génétique de la colonie ou au nombre d’accouplements des reines.

Le second axe de ce travail porte sur les stratégies de reproduction remarquables observées chez les espèces de Cataglyphis appartenant au groupe altisquamis :C. velox, C. mauritanica, C. humeya et C. hispanica. Ces espèces partagent une stratégie unique dans le règne animal, appelée hybridogénèse sociale. L’hybridogénèse classique est un système reproductif dans lequel les parents issus de lignées génétiques distinctes s’hybrident. Alors que les génomes maternels et paternels sont exprimés dans la lignée somatique des descendants, le génome paternel est systématiquement écarté de la lignée germinale. En conséquence, seul le génome maternel est transmis aux générations futures. Dans le schéma d’hybridogénèse sociale reporté dans ces travaux, les reines s’accouplent systématiquement avec un mâle originaire d’une lignée génétique distincte. Elles utilisent la reproduction sexuée pour la production d’une caste ouvrière stérile intégralement hybride (analogue à la lignée somatique) et la reproduction asexuée par parthénogénèse pour la production des castes reproductrices mâles et femelles (analogues à la lignée germinale). Dans ce système, bien que les génomes paternels et maternels soient exprimés dans la caste ouvrière, seul le génome maternel est transmis aux descendants reproducteurs [Chapitre 3]. Le groupe altisquamis est représenté par plusieurs espèces au sein desquelles deux lignées génétiques s’hybrident systématiquement pour la production de la caste ouvrière. Le dernier chapitre de cette thèse [4] est une analyse phylogéographique des espèces de ce groupe dans la péninsule ibérique. Les résultats confirment l’existence d’une seule paire de lignées génétiques au sein de chaque espèce. Ces résultats révèlent également une contradiction entre les marqueurs nucléaires et mitochondriaux traduisant la complexité du système reproductif. Ces travaux soulignent l’ambiguïté des relations phylogéniques entre espèces d’un tel système et discutent de son implication dans la spéciation des espèces hybridogénétiques.

Social insects represent the most extreme form of cooperative life in the animal kingdom. This is based on the existence of a division of reproductive activities between the reproductive individuals (queens and males) and a majority of workers performing all logistical tasks at the expense of their own reproduction. In social Hymenoptera, comparative analysis of reproductive strategies reveals that colonies headed by a single mated queen (monogyny/monoandry) is the ancestral structure of colonies. This structure provides a high genetic correlation between the workers and the brood they raise and, therefore, their overall reproductive success (inclusive fitness). However, an increasing number of genetic studies reveal that the reproductive structure of colonies can strongly differ from this pattern. This is particularly obvious in ants, which have a very large social polymorphism resulting in a large variability in the number of reproductive females within colonies. The Formicidae are also remarkable for the diversity of their modes of reproduction. This diversity relates to mating frequency (monoandry/polyandry) or conditional use of sexual and asexual reproduction. In some species, new queens are produced by parthenogenesis (they are almost clones of their mothers), while the workers arise from a classical sexual reproduction. By using alternative modes of reproduction for queen and worker castes, queens can increase the transmission rate of their genes to their reproductive female offspring while maintaining genetic diversity in the worker population. This high diversity of social structures and modes of reproduction suggests the occurrence of many selective forces. This thesis aimed at determining environmental and genetic factors responsible for the large social polymorphism and the high diversity of reproductive modes display by Cataglyphis desert ants. This thesis is divided into two main parts.

Phylogenetic analyses show that polyandry is ancestral across the genus Cataglyphis. The first part of this thesis examines the genetic hypothesis to account for the evolution and maintenance of multiple mating by queen in this genus. This work focuses on the benefits of increased genetic diversity among workers. Such genetic diversity may increase the size polymorphism of the worker force and improve efficiency of the division of labor [Chapter 1] or increase pathogen resistance of the colony [Chapter 2]. In Chapter 1, the genetic hypothesis to enhance efficiency of division of labor was tested on Cataglyphis cursor, a strictly monogynous and polyandrous species. The results reveal a great fidelity in task performance by workers. They reveal a significant association between patriline and task preference: workers belonging to different patrilines differ in their propensity to perform a given task. We also found that worker size is closely associated with task specialization. The second work of this thesis [Chapter 2] was performed in C. mauritanica. Our results show that resistance to pathogens differs between workers from different patrilines when patrilines are raised separately. Surprisingly, this difference disappears when the patrilines are grouped within polyandrous colonies. Therefore, polyandry would standardize the overall resistance of colonies. Consistent with this result, our data show a positive association between the number of matings by the queens and colony resistance to Metarhizium anisopliae.

The second part of this thesis expounds the unorthodox reproductive strategies observed in species belonging to the group Cataglyphis altisquamis: C. velox, C. mauritanica, C. hispanica and C. humeya. These species share a unique strategy in the animal kingdom, called social hybridogenesis. Hybridogenesis is a sexual reproductive system, whereby parents from different genetic origin hybridize. Both the maternal and paternal genomes are expressed in somatic tissues, but the paternal genome is systematically excluded from the germ line, which is therefore purely maternal. Consequently, only the maternal genome spread across generations. Here, we report a unique case of hybridogenesis at a social level. Queens mate exclusively with males originating from a different genetic lineage than their own to produce hybrid workers, while they use parthenogenesis to produce the male and female reproductive castes. In consequences, all sterile workers (somatic line) are sexually produced hybridogens, whereas sexual forms (germ line) are clonally produced. Thus, only maternal genes are perpetuated across generations [Chapter 3]. The group C. altisquamis is represented by several hybridogenetic species in which two highly divergent genetic lineages co-occur, despite their constant hybridization. The last chapter of this thesis [Chapter 4] is a phylogeographic analysis of C. altisquamis species in the Iberian Peninsula. Our results confirm the existence of a single pair of genetic lineages within each species. Our results also reveal strong incongruences between nuclear and mitochondrial markers that reflect the reproductive system complexities. These studies reveal phylogenetic ambiguities among these hybridogenetic species and discuss the involvement of such unconventional system in speciation process.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Viviès, France-Line. "Modes de domination et mécanismes de reproduction le cas de la Martinique /." Lille 3 : ANRT, 1989. http://catalogue.bnf.fr/ark:/12148/cb37619171j.

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Odena, Sophie. "Les modes de garde de la petite enfance : facteurs de reproduction sociale et sexuée." Aix-Marseille 1, 2005. http://www.theses.fr/2005AIX10059.

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A partir d'une enquête qualitative qui étudie deux modes de garde externalisés (crèches collectives et assistantes maternelles), cette thèse analyse l'exercice quotidien des rôles parentaux et les modes d'intervention des professionnels de la petite enfance dans les pratiques éducatives des familles. La première partie montre que si le choix du mode de garde se prend "in fine" au sein du couple, il est conditionné en amont par les mesures que l'Etat met à la disposition des familles. La deuxième partie est consacrée à l'étude des interactions entre les familles et les modes de garde. Les caractéristiques sociales des parents et leur attitude tout au long du processus d'obtention conditionnant l'issue de leur demande. La dernière partie s'intéresse aux représentations des rôles parentaux véhiculées par les institutions et à la manière qu'elles ont d'interférer avec celles de la famille. Il s'agit de montrer dans quelle mesure ces institutions contribuent à la reproduction sociale et sexuée.

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Rodriguez, Lily. "Diversité et modes de reproduction du peuplement d'anoures de Cocha Cashu (parc national Manu, Pérou)." Paris 6, 1991. http://www.theses.fr/1991PA066312.

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Pour tester l'hypothèse avancée par Duellman, selon laquelle la richesse spécifique des anoures est supérieure en régimes de pluies non saisonniers, on a étudié le peuplement d'anoures de Cocha Cashu (12 sud, au Pérou). On a ensuite comparé ces résultats à ceux des études faites par Crump et Duellman à Santa Cécilia (0, en Equateur), site connu comme étant le plus riche en espèces d'anoures. Les comparaisons mettent en relief les variations dans les traits de reproduction, la richesse spécifique et l'abondance relative. Le peuplement de Cocha Cashu se compose de 81 espèces. Sa richesse spécifique et sa diversité en modes de reproduction, comparables à celles du peuplement de Santa Cécilia, ne renforcent pas l'hypothèse de Duellman. Les comparaisons allométriques des traits de reproduction, montrent que à Cocha Cashu, la taille des femelles, l'effort de reproduction et le diamètre des oeufs ont tendance à être plus grands qu'à Santa Cécilia. Les comparaisons entre la plaine d'inondation et la forêt sur terrasse, ne montrent pas de différences quant au nombre d'espèces par mode de reproduction, mais les abondances relatives d'individus par mode de reproduction diffèrent significativement entre les deux habitats. La comparaison avec Santa Cécilia montre une tendance similaire

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Jalalzadeh, Moghaddam Shahri Banafsheh. "Evolution intraspécifique du génome et modes de reproduction générateurs de diversité génétique chez Agaricus bisporus." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0420/document.

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Agaricus bisporus, le champignon de Paris, est un basidiomycète saprophytenaturellement présent dans la litière de cyprès (Cupressus macrocarpa). Il possède différentsmodes de reproduction. Pour étudier leur rôle dans la dynamique spatio-temporelle et l’évolutionde la diversité génétique au cours du temps, des dispositifs expérimentaux ont été mis en place.Dix souches sauvages d’Agaricus bisporus var. bisporus ont été sélectionnées, à partir de deuxpopulations françaises, sur leurs traits phénotypiques et génotypiques. L’étude de l’évolutionmoléculaire de leurs génomes a montré que, pour le génome mitochondrial, la mobilité desintrons de groupe I apparait comme la principale source de polymorphisme. Des taux desubstitution nucléotidique (nt) faibles ont été observés chez tous les types de séquencesmitochondriales (éléments mobiles, séquences géniques et inter géniques). Cette forteconservation, comparée avec les taux élevés de substitution nt des séquences nucléairessimilaires, contraste avec ce qui est généralement décrit dans l’évolution des séquencesfongiques. Des expériences de croisements entre sporocarpes et mycelia de souches sauvages ontété menées sur du compost, dans une chambre de culture, pour simuler l’implantation d’unepopulation naturelle. Pour les sporocarpes récoltés, les données montrent l’existence d’unphénomène parasexuel de Buller conduisant à des souches hybrides d’A. bisporus dans lachambre de culture et potentiellement dans la nature. Parallèlement, les mycelia de souchessauvages ont été introduits dans deux parcelles expérimentales de cyprès. L’analyse génotypiquedes sporocarpes récoltés la première année d’introduction n’a pas permis de mettre en évidencede souche hybride et les conditions climatiques de la seconde année n’ont pas permis d’obtenir defructification. Les dispositifs et outils mis au point doivent permettre un suivi génétique spatiotemporelde la population sur le long terme
Agaricus bisporus, the button mushroom, is a saprophytic basidiomycete naturallyfound in cypress litter (Cupressus macrocarpa). It possesses different modes of reproduction. Tostudy their role in the spatio-temporal dynamics and in the evolution of the genetic diversity,experimental systems have been set up. Ten wild strains of Agaricus bisporus var. bisporus havebeen selected, from two french populations, on both phenotypic and genotypic traits. Themolecular evolution of their genomes has shown that, for the mitochondrial genome, group Iintron mobility was the main source of gene polymorphism. Low nucleotide (nt) substitutionrates were found in all types of mitochondrial sequences (mobile elements, genic and intergenicones). This stringent conservation of mitochondrial sequences, when compared with the high ntsubstitution rates of their nuclear counterparts, contrasts to what is widely accepted in fungalsequence evolution. Mating experiments between sporocarps and mycelia of wild strains wereconducted on compost in a room culture, to simulate the implantation of a natural population.Among the collected sporocarps, results indicate the occurrence of a parasexual Bullerphenomenon leading to hybrid strains of A. bisporus in room culture and putatively in the wild.In parallel, mycelia of the wild strains have been introduced in two experimental plots of cypress.Genotypic analysis of the sporocarps collected from these plots in the first year of introduction,failed to evidence a hybrid strain. The climatic conditions of the second year did not allowobtaining fruiting-bodies. The developed experimental systems and tools must allow a followingat the genetic level of the spatio-temporal evolution of the population

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Loizillon, Guillaume. "Modes de description des sons et synthese sonore." Paris 8, 1996. http://www.theses.fr/1996PA081164.

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Le son est defini comme la conjonction d'un phenomene physique et d'une realite physiologique et psychologique. Pourtant, seule la perception auditive fonde le phenomene acoustique dans sa specificite sonore. La mise en parallele des grandeurs physiques avec les donnees du sens de l'ouie est une conception limitee. Les travaux avances en psycho-acoustique montrent que l'audition ne peut se resumer en l'etablissement de ce reseau. Il faut considerer les sons comme les composantes d'une scene auditive dont la musique est un modele particulier. Il devient alors necessaire d'analyser les specificites du son musical, en suivant les etapes historiques qui ont conduit a une definition de celui-ci, articulee sur les parametres de hauteur, de duree d'intensite et de timbre. Cette derniere composante apparait comme valeur centrale dans la musique contemporaine. Ce basculement d'une musique des hauteurs vers une musique du timbre, prend un caractere decisif avec l'apparition des techniques electriques du son. En un siecle, elles ont apporte au musicien une panoplie d'outils qui utilisent les virtualites du son transforme en electricite, puis en informations numeriques. Au sein de ces nouvelles ressources, la seconde partie du travail se consacre a la synthese sonore. Sont abordes les differents modes de synthese sonore a travers un ensemble d'exemples sonores realises avec deux categories de programmes: les modes de synthese de signal, ou l'on specifie les differentes parametres de l'onde acoustique. Les modes de synthese par modeles physiques ou l'on decrit l'interaction entre differents objets modelises : cordes, plaques, plectres, anches. . . Par-dela la mise en oeuvre de processus techniques, l'objectif de ce travail est de demontrer que l'activite de synthese sonore est un veritable enjeu pour la composition qu'il serait une erreur de penser comme un seul produit de la technologie
SOUND IS DEFINED AS THE JUNCTION BETWEEN A PHYSICAL PHENOMENON AND PHYSIOLOGICAL A PSYCHOLOGICAL REALITY. MEANWHILE, ONLY THE AUDITIVE PERCEPTION - ESTABLISHES ACOUSTIC PHENOMENON ITS SOUNDING SPECIFICITY. LINKING PHYSICAL DIMENSIONS WITH ELEMENTS OF HEARING IS A RESTRICTED IDEA. LEADING WORKS IN PSYCHOACOUSTIC SHOW THAT AUDITION CANNOT BE REDUCED TO THIS CONCEPT. SOUNDS HAVE TO BE CONSIDERED AS THE ELEMENTS OF AN AUDITION SCENE OF WHICH MUSIC IS A SPECIFIC CASE. THUS, IT IS NECESSARY TO ANALYSE SPECIFICITIES OF MUSICAL SOUND, FOLLOWING THE HISTORICAL WAY THAT LEAD TO A DEFINITION ARTICULATED AROUND PARAMETERS OF PITCH, DURATION, INTENSITY AND TIMBRE. THIS LAST DIMENSION APPEARS AS A CENTRAL VALUE IN CONTEMPORARY MUSIC. THIS TRANSITION FROM A MUSIC OF PITCH TO A MUSIC OF TIMBRE, TAKES A DECISIVE DIMENSION with THE BIRTH OF ELECTRICAL SOUND TECHNICS. IN THE TIME OF ONE CENTURY THOSE TECHNICS BROUGHT MUSICIANS A COLLECTION OF TOOLS THAT USES THE CAPACITIES OF SOUND TRANSFORMED IN ELECTRICITY THEN IN DIGITAL INFORMATION. AMONG THOSE RESSOURCES, THE SECOND PART OF THIS WORK TAKES SOUND SYNTHESIS AS SUBJECT. WE DISCUSS IN THIS PART OF DIFFERENT SYNTHESIS METHODS AND WE SHOW DIFFERENT PROGRAMMING EXAMPLES, SEPARATED IN TWO CATEGORIES. METHODS OF SIGNAL SYNTHESIS IN WHICH ALL THE PARAMETERS OF ACOUSTIC WAVES MUST BE SPECIFIED. PHYSICAL MODELING WHERE THE INTERACTION BETWEEN OBJECTS LIKE STRING, PLATE, TUBE, MASS, IS DESCRIBED BEYOND A TECHNICAL PROCESS, THE GOAL OF THIS WORK IS TO DEMONSTRATE THAT SOUND SYNTHESIS IS A GENUINE PART OF MUSICAL COMPOSITION TERRITORY. IT WOULD BE A MISTAKE TO REGARD ONLY AS A TECHNOLOGICAL PRODUCT

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Ancel, Caroline. "Le RFRP-3 et l’axe gonadotrope du hamster syrien : effets genre-dépendants et modes d’action." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAJ042/document.

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Le peptide RFRP-3 joue un rôle dans la régulation de l’axe hypothalamo-hypophyso-gonadotrope des mammifères. Le but de cette étude était de déterminer l’implication du RFRP-3 dans la régulation de l’axe reproducteur du hamster Syrien. Nos résultats montrent que le RFRP-3 stimule l’axe gonadotrope chez le hamster Syrien mâle, tandis qu’il a des effets variables chez la femelle. En effet, chez la femelle le peptide inhibe l’axe reproducteur lorsqu’il est administré au moment du pic pré-ovulatoire de LH le jour du proestrus, et n’a pas d’effet pendant le diestrus. Nous avons poursuivi notre étude par la caractérisation des sites d’action du RFRP-3 chez le hamster Syrien, en démontrant que l’effet du peptide sur l’axe gonadotrope est médié directement ou indirectement par les neurones à GnRH. De plus, nous avons écarté l’hypothèse d’un effet hypophysiotrope du peptide chez cette espèce. Pour conclure, les résultats présentés soulèvent de nombreuses questions quant aux effets espèce- et genre-dépendants du RFRP-3 sur l’axe gonadotrope du mammifère
RFRP-3 has been shown to play a role in the regulation of the mammalian hypothalamic-pituitary-gonadal axis. The aim of this work was to determine the involvement of RFRP-3 in the regulation of the Syrian hamster reproductive axis. We report unprecedented results indicating that RFRP-3 stimulates the male Syrian hamster gonadotrophic axis, whereas it has variable effects in female Syrian hamsters. Indeed, in females the peptide inhibits the reproductive axis at the time of the LH surge on the day of proestrus, and has no effect during diestrus. We went on to characterize RFRP-3 sites of action in the Syrian hamster brain, and show that the effect of the peptide on the gonadotrophic axis is mediated directly or indirectly via GnRH neurons. Moreover, we clearly rule out the possibility of a hypophysiotrophic effect of RFRP-3 in this species. Taken together, the present data raise interesting questions regarding species- and sex-dependent effects of RFRP-3 on the mammalian gonadotrophic axis

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Souchon, Yves. "Reproduction du brochet (Esox lucius,L. 1758) et développement des brochetons en Dombes : éléments d'optimisation des modes de gestion extensive." Lyon 1, 1985. http://www.theses.fr/1985LYO10514.

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Souchon, Yves. "Reproduction du Brochet (Esox lucius, L. 1758) et développement des prochetons en Dombes éléments d'optimisation des modes de gestion extensive." Grenoble : ANRT, 1985. http://catalogue.bnf.fr/ark:/12148/cb37595184d.

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Delmotte, François. "Evolution des modes de reproduction chez le puceron Rhopalosiphum padi (L. ) : apports de la génétique des populations et de la phylogénie moléculaire." Rennes, Agrocampus Ouest, 2001. http://www.theses.fr/2001NSARA035.

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Chez certaines espèces de pucerons comme Rhopalosiphum padi, les lignées à parthénogenèse cyclique (sexuées) coexistent avec des lignées à parthénogenèse obligatoire (asexuées) La coexistence de lignées sexuées et asexuéss permet de comparer les conséquences génétiques de la perte de la sexualité, un point central dans le débat sur l'évolution et le maintien de la reproduction sexuée chez les eucaryotes. Par exempte, la diversité clonale des populations asexuées influence fortement l'issue de la compétition avec les lignées sexuées et détermine l'avantage éventuel de la reproduction sexuée. Bien que les pucerons présentent de fréquentes transitions de la parthénogenèse cyclique - qui est leur mode de reproduction ancestral -vers la parthénogenèse obligatoire, on ignore tout des mécanismes qui conduisent à la perte de la sexualité. Dans un premier temps, nous avons réalisé une analyse comparative de la structure génétique des populations sexuées et asexuées du puceron R padi' à l'aide de marqueurs microsatellites et allozymiques. Les allozymes se sont révélés fortement soumis à la sélection, remettant sérieusement en question les résultats des études antérieures sur la génétique des populations de pucerons. Une forte différentiation entre les lignées sexuées et asexuées a été trouvée avec les deux types de marqueurs. Dans les populations sexuées, les marqueurs microsatellites ont révélé une forte diversité génétique et un déficit en hétérozygotes résultant peut-être d'une sous structuration génétique. Bien que les populations asexuées possèdent un sous-échantillon de la diversité allélique des populations sexuées, elles présentent une importante diversité clonale et un fort excès en hétérozygotes à la plupart des locus microsatellites

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Ratajczak, Damien. "Spatiodynamiques de territorialisation des modes de production et de reproduction identitaires en espace transfrontalier : application à la réalité géographique du Hainaut franco-belge." Lille 1, 2000. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2000/50377-2000-21.pdf.

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Territoire transfrontalier à l'évolution chronogéographique longue et difficile, le Hinaut franco-belge, anciennement industrialisé et urbanisé reste surtout un espace-support à des faits et phénomènes géographiques en cours d'accomplissement -métropolosations inachevées, conurbanisation entre Valenciennes, Mons et Charleroi- , ou en ré-émergence, par le biais d'une subrégionalité polymorphe : pays, intercommunalité, agglomération. Son identité éventuelle doit fonctionner comme le produit réactualisé d'un complexe spatiodynamique, par confrontation classique entre urbanité et ruralité avec comme conséquence, la surrection d'espaces intermédiaires, induisant une sociodynamique spécifique, les populations hennuyères ayant des origines et des aspirations identitaires multiples voire antinomiques : les concept d'identité plurielle n'y est plus entièrement explicatif. La finalité des cette thèse de géographie humaine, culturelle et sociale est donc la détermination d'un espace social hennuyer clairement différencié d'autres territoires, spatialement ou culturellement équivalents , et partiellement impliqués dans son avenir : Cambraisis, Thiérache, Wallonie, Flandres. . . Existe-t-il une identité hennuyère territorialisée ? Si oui, est-elle transfrontalière ? Quelle est alors son échelle d'application voire d'applicabilité ? L'élargissement de cette problématique est plus formel : en quoi l'identité est-elle un concept géographique valide, dans le champ postmoderne actuel de la globilisation et de la mondialisation ? Comment mesurer géographiquement les procédures d'appropriation par le tissu associatif ? Le Hainaut est-il une réalité identitaire spatialisée, ou plus probablement, une trame référentielle commune à de multiples projets de développement local ?

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Plot, Virginie. "Caractéristiques maternelles, performances et stratégies de reproduction des tortues marines de Guyane." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00867096.

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Les organismes font face à des compromis entre leur reproduction, leur maintenance et leur survie, dont découlent des stratégies adaptatives énergétiques, comportementales et écologiques.Ce travail de thèse propose de préciser les stratégies de reproduction chez la tortue luth Dermochelys coriacea nidifiant en Guyane. Nous avons étudié les caractéristiques maternelles, les performances de reproduction et les potentiels liens existants entre la migration et la reproduction chez une population d'individus d'identité connue, suivis grâce à un suivi longitudinal original combinant biométrie, physiologie et biologie moléculaire.Premièrement nous montrons que les tortues luth opèrent comme des reproducteurs sur capital, i.e., leur reproduction repose sur les ressources stockées sous forme de réserves corporelles pendant la migration précédant la saison de ponte. D'autre part, nous suggérons que les femelles ajustent la durée de leur migration en fonction des conditions océanographiques rencontrées pendant la migration. Ceci leur permettrait, à l'échelle de la vie, de répondre au compromis entre la reproduction en cours et les reproductions futures. Enfin, notre démarche souligne l'importance de prendre en compte les caractéristiques individuelles dans la compréhension des stratégies de reproduction, et de manière ultime pour l'établissement de modèles réalistes de la dynamique des populations, notamment dans le cas d'espèces emblématiques telles que les tortues marines.

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Baudiffier, Damien. "Modes de perturbation de la stéroïdogenèse testiculaire et de la spermatogenèse chez le poisson zèbre (Danio rerio) par des fongicides azolés." Phd thesis, Université Rennes 1, 2012. http://tel.archives-ouvertes.fr/tel-00783232.

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Les azoles sont des fongicides présents dans les milieux aquatiques et connus pour inhiber des activités enzymatiques de cytochromes P450 (CYP). L'objectif de ce travail de thèse est de caractériser le mécanisme d'action d'un fongicide pharmaceutique, le clotrimazole sur la stéroïdogenèse testiculaire chez le poisson zèbre au travers l'étude d'un réseau de gènes fonctionnels le long de l'axe cerveau-hypophyse-gonade, et d'évaluer la capacité du clotrimazole à perturber la spermatogenèse. Nous montrons que le clotrimazole est capable d'affecter la stéroïdogenèse de manière différente in vitro et in vivo (i) des expositions d'explants testiculaires in vitro conduisent à l'inhibition de la synthèse de 11-kétotestostérone (11-KT), montrant une action directe de la molécule sur le testicule et (ii) l'exposition in vivo provoque une augmentation de l'expression de gènes impliqués dans le processus de la stéroïdogenèse. Nous avons ainsi mis en évidence un système de compensation biologique au niveau de l'organisme, avec un rôle prépondérant de la voie Fsh/FshR dans la médiation des effets du clotrimazole. Enfin, des effets sur la spermatogenèse ont été observés in vivo suite à une exposition chronique au clotrimazole, avec notamment une augmentation de la masse gonadique et du nombre de cellules de Leydig. Les effets tissulaires observés sont cohérents avec des effets mesurés au niveau moléculaire. L'ensemble de ces données montre l'intérêt de la démarche expérimentale utilisée pour caractériser le mécanisme d'action du clotrimazole. Ce travail ouvre de nombreuses perspectives, en premier lieu sur l'étude de l'impact fonctionnel du clotrimazole sur la reproduction.

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Ndifon, Abraham Nsah [Verfasser], and Einhard [Akademischer Betreuer] Schierenberg. "Variations of developmental events, skn-1 and pie-1 expression, and gene regulatory networks in nematodes with different modes of reproduction / Abraham Nsah Ndifon. Gutachter: Einhard Schierenberg." Köln : Universitäts- und Stadtbibliothek Köln, 2013. http://d-nb.info/1052307426/34.

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Stubblefield, Andrew T. "Coupled oscillations the reproduction and analysis of the oscillatory modes of a string/spring/mass pendulum and the derivation of the theoretical equations governing the motion of the mass ; an honors thesis /." [Jefferson City, Tenn. : Carson-Newman College], 2009. http://library.cn.edu/HonorsPDFs_2009/Stubblefield_Andrew_T.pdf.

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Joly, Hervé. "Diriger une grande entreprise française au XXe siècle : modes de gouvernance, trajectoires et recrutement." Habilitation à diriger des recherches, Ecole des Hautes Etudes en Sciences Sociales (EHESS), 2008. http://tel.archives-ouvertes.fr/tel-00343525.

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Ce dépôt correspond à l'ensemble du "mémoire inédit" du dossier d'habilitation à diriger des recherches dont le titre général est "Dirigeants d'entreprise et élites économiques en France et en Allemagne au XXe siècle. Formations, trajectoires individuelles et stratégies des firmes". Il comporte également un "mémoire de synthèse" dont le titre est "De la sociologie à la prosopographie historique des élites : regards croisés sur la France et l'Allemagne" (158 p.) et un recueil de 23 articles publiés. Le mémoire inédit est une étude dont le corpus statistique principal porte sur 194 dirigeants (présidents, administrateurs délégués, PDG et directeurs généraux) de 21 grandes entreprises industrielles françaises entre 1914 et 1966. Il est complété de manière ponctuelle par de nombreux prolongements dans d'autres secteurs, en amont et en aval dans le temps (avec notamment des contrepoints pour le temps présent à la fin de chaque chapitre) et sur des populations dirigeantes élargies. Sont successivement étudiés, dans une première partie consacrée aux modes de gouvernance, la répartition des fonctions dirigeantes (chapitre 1), l'importance des logiques familiales (chapitre 2), les conditions d'accès, d'exercice et de sortie des fonctions dirigeantes (chapitre 3) et, dans une seconde partie consacrée aux trajectoires et au recrutement, la fermeture scolaire du recrutement (chapitre 4), le poids des grands corps (chapitre 5) et l'origine sociale entre reproduction et ascension (chapitre 6).

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Ferasyi, Teuku Reza. "Mathematical model of the reproductive endocrine system in male sheep." University of Western Australia. School of Animal Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0080.

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[Truncated abstract] The activity of the reproductive endocrine axis is the result of interactions among many organs and tissues, particularly the hypothalamus, pituitary gland and gonad. However, it depends on more than the communication between anatomical structures because it is also affected by genotype, internal factors (e.g., metabolic inputs) and external factors (e.g., photoperiod, socio-sexual cues, stress, nutrition). This multifactorial complexity makes it difficult to use animal experimentation to investigate the pathways and mechanisms involved. Therefore, in this study, I have turned to mathematical modelling. The general hypothesis was that, by modelling the hormonal feedback loop that links the hypothalamus, pituitary gland and gonad, I would be able to discover the critical control points in this homeostatic system. This would allow me to inform and direct research into the processes that control reproduction, including inputs from environmental factors. My studies began with the development of a model of the negative feedback loop through which testosterone controls the secretion of pulses of gonadotrophin-releasing hormone (GnRH) by the hypothalamus. The model incorporated two critical factors: testosterone concentration and a time delay in the inhibition of the activity of the GnRH 'pulse generator' by testosterone. The general assumptions were: i) there are two positive feedforward processes (GnRH pulses stimulate LH pulses, and, in turn, LH pulses stimulate testosterone secretion); ii) testosterone exerts negative feedback that reduces the frequency of GnRH pulses. The model incorporated a group of equations that represent the GnRH pulse generator, through which the inhibitory effect of testosterone acted to reduce GnRH pulse frequency. Simulations were run with various values for the time delay in feedback and, as model development progressed, the simulations were extended to include combinations of time delays and levels of sensitivity of the GnRH pulse generator to inhibition by testosterone. The output of the simulations showed clearly that a time delay in negative feedback, as well as the concentration of testosterone, can greatly affect the frequency of GnRH pulses and the shape of the GnRH secretory profile. Importantly, the effect of the time delay depends on the sensitivity of the pulse generator to testosterone. In addition, the simulations suggested two additional components that might be involved in the control of the GnRH pulse generator: i) a delay in the rate of adaptation to a change in steroid feedback; and ii) a minimum pulse interval (maximum frequency). These studies iii therefore suggest that the regulation of the activity of the GnRH pulse generator, and thus the frequency and profile of GnRH and LH pulses, requires interactions among these four components. These interactions should be tested in animal experimentation. In the next stage, I extended the model so I could test whether the feedback delay might involve the process of aromatization in which testosterone is converted to oestradiol at brain level. ... This information can be used to direct future experimental studies that will help us to understand the factors that underlie the dynamic behaviour of the hypothalamic and pituitary systems that control reproduction.

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Larkin, Katelyn. "Effects of polyploidy and reproductive mode on life history trait expression." Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1673.

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Although genomes are perhaps the single most important element of living systems, why they feature such striking variation and how this variation is maintained within and across natural populations remains unclear. One of the most common and important means by which genomic variation is generated is ploidy elevation. While polyploidy has been implicated in the remarkably successful radiations of angiosperms, teleost fish, and amphibians, the phenotypic consequences of changes in ploidy level are poorly understood, especially in animals. I use a large, multi-year common garden experiment to identify potential life history costs and benefits of polyploidy and asexual reproduction, a trait often associated with polyploidy, in Potamopyrgus antipodarum. This snail is well suited for studying ploidy variation and sex because diploid sexuals and triploid and tetraploid asexuals frequently coexist, allowing us to use comparisons of sexuals to asexuals and triploid to tetraploid asexuals to study both the effects of ploidy elevation and sex. I detected a strong negative correlation between growth rate and time to maturity and found that sexual P. antipodarum grew and matured significantly more slowly than the polyploid asexuals. Sexual P. antipodarum were also more likely to die before achieving reproductive maturity than their asexual counterparts. By contrast, there were no apparent life history differences between triploid and tetraploid asexuals, indicating that direct phenotypic benefits of ploidy elevation are unlikely to explain the relatively rapid growth and maturation of asexuals. My results suggest that ploidy elevation does not inevitably confer phenotypic consequences, that reproductive mode influences life history trait expression, and that sexual P. antipodarum persist in many natural populations in spite of substantial life history disadvantages.

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Ndungutse, Jean-Claude. "Évolution de la population, modes de production et reproduction, rapports sociaux et développement rural : une approche des dynamiques démographiques dans leur contexte historique, économique, social, politique et culturel et leur interaction sur l'évolution des forces productrices, leurs rapports sociaux et modes de production dans le milieu rural agricole au Rwanda de l'époque pré-coloniale à 1994." Paris, EHESS, 2009. http://www.theses.fr/2009EHES0159.

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La plupart des chercheurs (historiens, démographes, sociologues, anthropologues et autres experts qu'ils soient nationaux ou internationaux) qui ont travaillé sur le Rwanda affirment que l'accroissement rapide et la forte densité qui caractérisent sa population sont les signes d'un surpeuplement qui serait à l'origine de la pauvreté et une entrave au décollage économique de ce petit pays de l'Afrique centrale. D'autres avancent l'idée selon laquelle la guerre de 1990 et son point culminant qu'est le génocide de 1994 prendraient leur origine dans cette croissance démographique galopante et non maîtrisée qui aurait provoqué une promiscuité sociale étouffante où chaque groupe social aurait tenté de se trouver une place et un statut social. Tout en acceptant l'idée que l'équilibre entre population et ressources peut présenter structurellement des moments malthusiens, Jean-Claude Ndungutse montre que, tout au long de l'évolution de la société rwandaise, d'autres facteurs ont joué notamment les aléas climatiques, les modes de productions déséquilibrés, les ravageurs des plantes comme des criquets pèlerins et autres facteurs sociaux (violences, inégalités sociales, mauvaise gouvernance et crimes politiques, maladies et autres. . . ) qui tous, ont contribué à la dégradation du potentiel productif dans le milieu rural agricole au Rwanda. Jean-Claude Ndungutse s'inscrit dans la vision d'Esther Boserup et aborde le sujet dans une approche historique, sociologique et anthropologique
The main part of local and international researchers (historians, demographers, sociologists, anthropologists and other experts) who have worked on Rwanda say that the speedy increase and the high density characterizing its population are signs of underdevelopment which is a source of poverty and a hamper of the economic take off of that small country located in the central Africa. Other people believe that the 1990 war which led to 1994 genocide have their main origin in the galloping and non controlIed increase of population which provoked a tough social promiscuity where each social group tries its best to get a room and a social status. If we do accept the idea that the equilibrium between a population and its resources may structurally conduct to Malthusian moments, Jean-Claude Ndungutse shows that during the changes of the Rwandese society, some other factors such as climatic ales the inadequate production system, the plantations invaders such as insects and other social factors (violence, social inequity, bad governance and political crimes, illness, etc. . . ) should be taken into account to explain the situation. AlI of them had contributed to deteriorate the production potentials in the Rwandese agricultural rural area. Jean-Claude Ndungutse has the same point of view as Esther Boserup and treats the subject in a historical, sociological and anthropological approach

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Cheung, Kai Chung. "Facultative sex model /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?MATH%202008%20CHEUNG.

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Hernandez, Marcel Luis. "Optimisation models of courtship and reproduction." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297710.

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Mallery, Christopher Sean. "Reproduction and Metabolic Responses to Acute and Chronic Hypoxia in Ovoviviparous Blaberid Cockroaches, with a Focus on Blaptica dubia." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011879/.

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The major components of the tracheal system of insects are an extension of the exoskeleton, and the size of the exoskeleton is fixed in the adult stage, so any increase in metabolic demand that may accompany reproduction must be met by a relatively unaltered tracheal system that the female set in place at ecdysis, when entering adulthood. Acute hypoxia tends to elicit an increase in ventilation in insects, and here, I observe increased interburst VCO2 release, and a tendency towards a more continuous gas exchange pattern being preferred over discontinuous gas exchange when Blaptica dubia and Eublaberus posticus are exposed to a descending regime of hypoxia. Additionally, higher temperatures appear to increase sensitivity to hypoxia in these species, an expected result because both species, like most ectothermic animals, display a Q10 effect, increasing metabolic rates as temperature increases. The reproductive mode of B. dubia is considered to be lecithotrophic pseudoviviparity (or type A ovoviviparity), and by the time the embryos are born, they have more than doubles in volume from the time of oviposition. This gain is apparent in the wet mass of the embryo, with no change occurring in dry mass. The egg mass that can be attributed to water begins at 39% at oviposition and increased to nearly 82% at hatching. The metabolic rates of females and embryos increase as embryonic development progresses, but bomb calorimetry reveals that energy content of the embryos does not change. It is possible that these embryos gain some nutrition from the mother during embryonic development, but direct evidence remains to be demonstrated. Blaptica dubia and Eublaberus posticusare both blaberid species that display the same reproductive mode, pseudoviviparity, with incubation occurring in a brood sac. Comparisons between the reproductive traits of B. dubia and E. posticus reveal that the two species have similar reproductive periods, interbirth periods, and clutch sizes to one another, and that both have reproductive cycles and incubation times intermediate to oviparous species and the one species of cockroach that some consider to be truly viviparous (Diploptera punctata). However, whereas adult female E. posticus are larger than female B. dubia (E. posticus non-gravid female mass: 2.91 +/- 0.42 g, 20; B. dubia non-gravid female mass: 2.60 +/- 0.40 g, 20), the offspring of B. dubia are larger than those of E. posticus at the time of birth (B. dubia neonate mass: 24.70 +/- 4.01 mg, 19; E. posticus neonate mass: 22.40 +/- 1.36 mg, 19). Both gravid and non-gravid female B. dubia respond similarly to acute hypoxia exposure, increasing mean total VCO2. However, the reproductive state does not appear to exacerbate, nor dull, the acute response to hypoxia. Gravid and non-gravid female B. dubia were exposed to chronic hypoxia for 30 days and 45 days. Relatively high mortality was observed in nearly all chronic hypoxic treatment groups as compared to controls at 21 kPa O2. Comparing treatment groups to controls maintained at 21 kPa O2, embryo mass was not decreased, nor was embryo VCO2 at day 30. Adult female B. dubia metabolic rates did not show a consistent change in response to chronic hypoxia, but decreased metabolic rate was observed in the non-gravid B. dubia exposed to chronic 4 kPa O2, an observation that is consistent with past studies in insects. Survival rates were lower for both gravid and non-gravid females in 4, 8, and 12 kPa O2, as well as in 15 kPa O2 in gravid females, as compared to 21 kPa O2. Gravid females experiences a decreased survival rate compared with non-gravid females at 12 and 15 kPa O2, but gravid and non-gravid females had similarly low survival rates at 4 and 8 kPa O2. This difference in survival rates suggests there is a cost associated with carrying an ootheca in a brood sac, resulting in an increased sensitivity to hypoxia, at least over a long period of time.

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Pound, Graeme Edward. "Ecological models of the maintenance of sexual reproduction." Thesis, University of Southampton, 2001. https://eprints.soton.ac.uk/45919/.

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A generic model of the interaction between sexual and asexual morphs in an ecological context was developed from the lotka-Volterra model of the population dynamics of two competing species (Doncaster, Pound & Cox, 2000). This revealed the threshold difference between the resource niches of sexual and asexual populations that allows coexistence between the two morphs. Coexistence depended on the respective carrying capacities of the sexual and asexual competitors, which we showed to be contingent upon the intrinsic growth capacity of the sexual population. The analytical model was extended to study (a) competition between a sexual population and numerous asexual clones; (b) competition between two metapopulation. A special formulation of Slatkin’s (1974) three-dimensional model of two competing metapopulations was developed with Lotka-Volterra dynamics, which yielded novel predictions for the behaviour of local and regional communities of species. Coexistence between sexual and asexual morphs maybe unsustainable due to the accumulation of clonal diversity over time, and indeed coexistence is rarely observed in nature. To study the dynamics of this accumulation, a stochastic model was developed for competition between asexual clones and a genetically diverse sexual population that exploits a range of resource niches. A model of the accumulation of deleterious mutations over time was incorporated into this framework. Monte-Carlo simulations demonstrated that a sexual population may, over time, exclude asexual clones whose fitness deteriorates due to the accumulation of deleterious mutations. These results suggest that whilst coexistence between sexual and asexual morphs is possible over ecological timescales the long-term outcome of an asexual invasion is determined by: 1) The relationship between genetic variation and niche breadth in the sexual population. 2) The rate as which the relative fitness of the asexual population declines with mutation accumulation. Reciprocal scenarios of the invasion of an asexual population by sexual mutants and sexual colonists are also considered.

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Мельник, Леонід Григорович, Леонид Григорьевич Мельник, Leonid Hryhorovych Melnyk, Олександр Миколайович Дериколенко, Александр Николаевич Дериколенко, Oleksandr Mykolaiovych Derykolenko, Олександр Васильович Кубатко, et al. "Business Models of Reproduction Cycles for Digital Economy." Thesis, CEUR-WS, 2019. http://essuir.sumdu.edu.ua/handle/123456789/74617.

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The intensive use of non-renewable resources and torn technological cycles is the cause for the total destruction of the planet’s ecosystems. The transition of production systems to renewable resources and closed circular cycles can ensure long-run sustainability of economic activities. Circular technologies as the basis of business processes guarantee sustainable transformation of the usual economy to digital one. The reproduction of economic activities in the closed integral cycle “production-interfacing-consumption-recyclingproduction” is the principal condition for the successful functioning of business processes. The scientific grounding, design and practical implementation of reproductive circular business processes create the platform for building a digital economy and ensures ecosystems sustainability. The research focuses on the modeling, design and practical implementation (introduction, testing, refinement, and adaptation to specific conditions) of reproductive circular business processes. The research models economic activity and communication of the economic agents in the main areas of the digital economy.

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Birget, Philip Laurent Guillaume. "Evolutionary ecology of parasites : life-history traits, phenotypic plasticity, and reproductive strategies." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28805.

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Adaptive phenotypic plasticity, the ability of a genotype to give rise to different phenotypes in different environments, evolves to allow organisms to fine-tune their life-history traits according to the varying conditions they encounter during their lives. Reproductive investment - the manner in which organisms divide their resources between survival and reproduction - is well studied in evolutionary ecology because it is a key determinant of fitness. However, whilst plasticity in reproductive effort is well understood for free-living multicellular taxa (such as insects, birds, and mammals), the application of evolutionary theory for plasticity and life history strategies to unicellular parasites and pathogens is lacking. In this thesis, I use empirical and theoretical approaches to uncover how differential resource allocation to non-replicating, sexual stages (gametocytes) versus asexually replicating stages can be harnessed by the rodent malaria parasite Plasmodium chabaudi to maximise its fitness across the often very variable conditions it encounters during infections. Differential allocation between those stages is equivalent to the fundamental life-history trade-off between survival and reproduction because gametocytes are responsible for between-host transmission (i.e. reproduction of the infection) whereas asexual parasites mediate host exploitation and within-host survival. A suite of within-host models reveal that malaria parasites could gain considerable fitness benefits in the face of low levels of drug treatment if they reduce their investment into gametocyte production ("reproductive restraint"), thereby assuring the continuity of the infection and capitalising on opportunities for future transmission. In contrast, high levels of drug treatment typically select parasites to commit all of their resources to gametocyte production ("terminal investment"), to escape a host that does not offer much opportunity for future transmission. My experiments reveal that P. chabaudi increases both its reproductive investment and its asexual replication rate in anaemic hosts (i.e. host that have a low density of red blood cells), suggesting that parasites profit from host anaemia and can afford high investment in gametocytes ("affluent investment"). I also uncover plasticity in a number of traits that underpin asexual replication rate, including invasion preference for different ages of red blood cells, but it is plasticity in the number of progeny (merozoites) per infected cell that is the main contributor to asexual replication rate. My experiments also reveal genetic variance in plasticity of the life-history traits investigated, which has profound implications for their evolution. Furthermore, plastic modification of these traits is associated with minimal costs or constraints, so that parasites can rapidly match life-history traits appropriately to the within-host environment. Severe anaemia is one of the deadliest symptoms of malaria, so observing that virulence and infectiousness increases in anaemic hosts has also fundamental clinical implications. Finally, the empirical and theoretical observations of affluent investment, reproductive restraint and terminal investment match theoretical predictions of how organisms should behave in varying environments, confirming P. chabaudi as a useful model system to test life-history theory.

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Banet, Amanda Inez. "Evolutionary diversification of reproductive modes in livebearing fishes." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1957301301&SrchMode=2&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268858219&clientId=48051.

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Thesis (Ph. D.)--University of California, Riverside, 2009.
Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 17, 2010). Includes bibliographical references. Also issued in print.

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Chiacchierini, Lisa M. "Experimental design issues in impaired reproduction applications." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-151533/.

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Bobic, Gavrilovic Bojana. "Reproductive patterns in the domestic dog : a retrospective study, with the Drever breed as model /." Uppsala : Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/10639782.pdf.

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Webster, Matthew Paul. "Formal models of reproduction : from computer viruses to artificial life." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501590.

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In this thesis we describe novel approaches to the formal description of systems which reproduce, and show that the resulting models have explanatory power and practical applications, particularly in the domain of computer virology. We start by generating a formal description of computer viruses based on formal methods and notations developed for software engineering. We then prove that our model can be used to detect metamorphic computer viruses, which are designed specifically to avoid well-established signature-based detection methods. Next, we move away from the specific case of reproducing programs, and consider formal models of reproducing things in general. We show that we can develop formal models of the ecology of a reproducer, based on a formalisation of Gibson's theory of affordances.

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Handy, John R. "Line reproduction in mapping utilizing the four color process model /." Online version of thesis, 1992. http://hdl.handle.net/1850/11167.

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Huffman, Jennifer Wade. "Optimal Experimental Design for Poisson Impaired Reproduction Studies." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30751.

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Impaired reproduction studies with Poisson responses are among a growing class of toxicity studies in the biological and medical realm. In recent years, little effort has been focused on the development of efficient experimental designs for impaired reproduction studies. This research concentrates on two areas: 1) the use of Bayesian techniques to make single regressor designs robust to parameter misspecification and 2) the extension of design optimality methods to the k-regressor model. The standard Poisson model with log link is used. Bayesian designs with priors on the parameters are explored using both the D and F-optimality criteria for the single regressor Poisson exponential model. Since these designs are found via numeric optimization techniques, Bayesian equivalence theory functions are derived to verify the optimality of these designs. Efficient Bayesian designs which provide for lack-of-fit testing are discussed. Characterizations of D, D_s, and interaction optimal designs which are factorial in nature are demonstrated for models involving interaction through k factors. The optimality of these designs is verified using equivalence theory. In addition, augmentations of these designs that result in desirable lack of fit properties are discussed. Also, a structure for fractional factorials is given in which specific points are added one at a time to the main effect design in order to gain estimability of the desired interactions. Robustness properties are addressed as well. Finally, this entire line of research is extended to industrial exponential models where different regressors work to increase and/or decrease a count data response produced by a process.
Ph. D.

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Chen, Hua, Jun-Feng Li, and Wei-An Liu. "Behavior of the solution to a chemotaxis model with reproduction term." Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2009/3030/.

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34

Bui, Linh Thuy. "Molecular dissection of asexual reproduction in the model fern Ceratopteris richardii." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/6380.

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The life cycle of all land plants is characterized by the alternation between two multicellular generations: haploid gametophytes and diploid sporophytes. Whereas meiotic recombination and fertilization via sexual reproduction is known to confer adaptive evolutionary benefits, some plant species can reproduce asexually bypassing meiosis and fertilization yet still undergo alternation of generations. In ferns, the two asexual reproductive pathways are termed apogamy and apospory, i.e. the asexual reproduction of sporophytes and gametophytes, respectively. Although understanding the process of asexual reproduction in flowering plants would be of considerable agricultural value, the molecular mechanisms underlying this process have yet to be identified. Similarly, the genes in ferns that underlie apogamy and apospory are unknown. Knowledge of such genes will provide invaluable information not only for the evolutionary study of asexual reproduction in land plants, but also insight into the developmental program for each generation. My PhD research focuses on the investigation of candidate genes involved in asexual reproduction in the model fern Ceratopteris richardii. Though the molecular mechanisms underlying asexual reproduction are not understood, it is hypothesized that asexual reproduction is the result of altered regulation of certain sexual reproduction-related genes. Therefore, I selected candidate genes for asexual reproduction in C. richardii, CrEMS1, CrKNOX3 and CrANT, based on the functions of their respective homologs during sexual reproduction in two other model systems: Arabidopsis thaliana and Physcomitrella patens. I showed that, in C. richardii, CrEMS1 is expressed during key events of sexual reproduction, including sporogenesis, gametogenesis and embryo development; CrKNOX3 expression is specific for the mature egg cells and CrANT expression is restricted to sperm cells. The presence of CrEMS1 during early embryo development made it a suitable candidate for an embryonic marker for future research. To study the function of the candidate genes, I overexpressed CrKNOX3 and BnBBM, a flowering plant BBM gene that has similar expression patterns in Brassica to CrANT. The overexpression of CrKNOX3 results in unique cell outgrowth from the antheridia, and overexpression of BnBBM results in spontaneous apogamy induction. Whole mount in situ also showed CrEMS1 expression, marking embryonic identity, in pre-apogamous cells undergoing sugar-induced and overexpression of BnBBM-induced apogamy. The results of my PhD research provides, for the first time, insight into the molecular mechanisms underlying asexual reproduction in the model fern C. richardii, and invaluable tools, transient and stable Agrobacterium-mediated transformation protocols, for functional genomics research in this fern. The spontaneous apogamy induction on BnBBM-expressing gametophytes and the presence of CrEMS1 in pre-apogamous cells confirm the hypothesis that asexual reproduction is the result of the alteration in expression of sexual-related genes, verifying that the two pathways share a common set of genes.

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Grosmaire, Manon. "Caractérisation du mode de reproduction pseudogame chez l’espèce de nématode Mesorhabditis belari." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1151/document.

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Chez les espèces pseudogames, les femelles utilisent les spermatozoïdes des mâles d'autres espèces pour activer leurs ovocytes et produire de nouvelles femelles sans utiliser l'ADN paternel. Ici, nous montrons un nouveau mode de reproduction pseudogame découvert chez l'espèce de nématode Mesorhabditis belari chez qui 8% de mâles conspécifiques sont présents. Ces mâles sont nécessaires pour féconder les ovocytes mais leurs gènes ne seront transmis qu'à leur fils et non à leurs filles. En effet, les femelles produisent deux types d’ovocytes, un type amphimixique où les ADN paternel et maternel constitueront le génome du zygote qui deviendra un mâle et un type gynogénétique ou l’ADN paternel déclenchera le développement du zygote mais où seul l’ADN maternel constituera le génome du zygote qui deviendra une femelle. Ainsi, la production de mâles n'a pas d'incidence sur la diversité génétique des femelles. Par une approche de théorie des jeux, nous avons montré que la production des mâles dans une faible proportion constitue une stratégie évolutivement stable seulement si les fils sont plus enclins à se reproduire avec leurs sœurs. Nous avons validé cette prédiction par une approche expérimentale en montrant une préférence entre les frères et les soeurs pour la reproduction.En parallèle, nous nous sommes intéressés aux bases moléculaires et cellulaires soutenant un tel mode de reproduction. Dans les embryons amphimixiques, la méiose femelle produit un pronoyau haploïde et la diploïdie est restaurée grâce au pronoyau paternel également haploïde. Dans les embryons gynogénétiques, l’ADN paternel ne se décondense pas, la méiose femelle est incomplète et produit un pronoyau diploïde afin de maintenir la diploïdie du zygote. Nous avons donc étudié le développement précoce des embryons de M. belari, et essayé de comprendre le type de déterminisme du sexe présent chez cette espèce
In pseudogamous species, females use the sperm of males from another species to activate their oocytes and produce females, without using the sperm DNA. Here we report a novel reproductive strategy found in the pseudogamous nematodeMesorhabditis belari, which produces its own males at low frequency. We find that the 8% of M. belari males are necessary to fertilize all oocytes but pass on their genes only to males, and never to females. Thus, the production of males has no impact on the genetic diversity of females. Using game theory, we show that the production of males at low frequency constitutes an efficient strategy only if sons are more likely to mate with their sisters. We validate this prediction experimentally by revealing a mating preference between siblings. We uncover the remarkable reproductive strategy of parthenogenetic females that pay the cost of producing males while males do not spread their genes.In parallel, we tried to understand the cellular and molecular basis at the origin of such a reproductive mode. In amphimixis embryos, female meiosis produces an haploid pronucleus and ploidy is restored with the male haploid pronucleus. In gynogenetic embryos, paternel DNA don't decondense, female meiosis is incomplete leading to a diploid pronucleus in order to maintain the diploidy of the organism. We then studied the early development of the embryos of M. belari and the type of sex determinism in this species

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36

Morrill, Benson H. "Quantitative Genetic Analysis of Reproduction Traits in Ball Pythons." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1005.

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Although the captive reproduction of non-avian reptiles has increased steadily since the 1970’s, a dearth of information exists on successful management practices for large captive populations of these species. The data reported here come from a captive population of ball pythons (Python regius) maintained by a commercial breeding company, The Snake Keeper, Inc. (Spanish Fork, UT). Reproductive data are available for 6,480 eggs from 937 ball python clutches. The data presented suggest that proper management practices should include the use of palpation and/or ultrasound to ensure breeding occurs during the proper time of the female reproductive cycle, and that maintenance of proper humidity during the incubation of eggs is vitally important. Ball python reproduction traits (clutch size, clutch mass, relative clutch mass, egg mass, hatch rate, egg length, egg width, hatchling mass, healthy offspring per clutch, week laid, and days of incubation) were recorded for the clutches laid during this study. For the 937 clutches, the identity of the dam and sire were known for 862 (92%) and 777 (83%) of the clutches, respectively. A multivariate model that included nine of the 11 traits listed above was compiled. Heritability and genetic and phenotypic correlations were calculated from the multivariate analysis. The trait that showed the most promise for use in artificial selection to increase reproduction rates was clutch size due to considerable genetic variation, high heritability, and favorable genetic correlations with other reproduction traits. Although large datasets have been published for twinning in avian species, relatively few are available for non-avian reptiles. Reported here are 14 sets of twins produced from 6,480 eggs from 937 ball python clutches. The survival rate for twins during the first 3 months of life in our study was 97%. Interestingly, 11 of the sets of twins were identical in sex and phenotype, and additional genetic data suggested the rate of monozygotic twinning within this captive population of ball pythons was higher than that of dizygotic twinning. Further, using microsatellite analysis we were able to generate data that shows three sets of python twins were genetically identical.

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Gurgel, Priscila Cabral Silveira. "Reproductive modes are associated to climatic niche evolution in treefrogs (anura: hylidae)." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6263.

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The similarity of life-history traits among closely related species is a well-known pattern in evolutionary biology. Thus, closely related species tend to be more akin to each other than to distantly related ones. The propensity of closely related species to conserve climatic niche features over macroevolutionary time can be defined as climatic niche conservatism. Recent studies have shown the importance of environmental variables with regards to the diversity and distribution of anurans with differences in their reproductive traits under an evolutionary perspective. In this work, using frog species in the Hylidae family, we tested the hypothesis that species more independent from main bodies of water for reproduction are restricted to areas with higher temperature and precipitation means. We also investigated the evolution of climatic niche features of species with different degrees of dependence on water for reproduction. Our results corroborate the first hypothesis and show that terrestrial egg-laying species, in the Hylinae subfamily, have more conserved climatic niche position when compared to Hylinae species that deposits their eggs and tadpoles in main water bodies. Thus, we suggest that reproductive modes are associated with variation in the evolution of climatic niches of frogs.
A similaridade entre atributos de espécies aparentadas é um padrão tradicional reconhecido em biologia evolutiva. Espécies aparentadas tendem ser mais similares entre si do que com espécies não aparentadas. A tendência de espécies aparentadas conservar as características de seu nicho ao longo do tempo macroevolutivo pode ser definido como conservação filogenética de nicho. Estudos recentes tem mostrado a importância das variáveis climáticas na distribuição de anfíbios anuros com diferentes modos reprodutivos utilizando uma abordagem evolutiva. Neste trabalho, usando as espécies de pererecas da família Hylidae, testamos a hipótese de que espécies menos dependentes dos corpos d'água para reprodução ocorrem em áreas mais quentes e mais úmidas. Além disso, investigamos como foi a evolução dos atributos do nicho climático (posição e amplitude) de espécies, da subfamília Hylinae, com diferentes níveis de dependência dos corpos d'água para reprodução. Nossos resultados corroboram a primeira hipótese e mostram que, espécies da subfamília Hylinae que depositam seus ovos fora da água estão restritas a lugares mais quentes e mais úmidos. Além disso, tais espécies tem o nicho climático mais conservado do que espécies que depositam tanto ovos como girinos em corpos d'água principais. Portanto, sugerimos que os diferentes modos reprodutivos refletem em diferenças na evolução do nicho climático nas espécies da subfamília Hylinae.

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Dancho, Matthew G. "Age, Growth, and Reproduction of the Pelagic Stingray Pteroplatytrygon violacea in the Western North Atlantic Ocean." NSUWorks, 2013. http://nsuworks.nova.edu/occ_stuetd/140.

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Pteroplatytrygon violacea is the only member of the Dasyatidae family that exhibits an entirely pelagic behavior. Age, growth and reproduction characteristics were estimated for western north Atlantic populations, where it is a common bycatch species of commercial pelagic longline fisheries targeting swordfish and tuna. Ages were assigned by counting band-pair deposition on vertebral centra sections. An annual pattern of band-pair deposition was validated through marginal increment analyses. Age estimates ranged from 2.5 to 8 years for males and 3 to 10 years for females. The von Bertalanffy growth model, a modified form of the von Bertalanffy, a two-parameter form of the von Bertalanffy with a fixed length-at-birth, the Gompertz growth model and a logistic model were fitted to sex-specific observed size-at-age data. Models were fitted using maximum likelihood estimation and nonlinear least squares methods. Resulting models were evaluated based on biological rationale and Akaike’s information criteria. All growth models yielded similar estimates, however the two-parameter Von Bertalanffy growth model provided the best fit for both males (L∞ = 54.79 cm (Disc width, DW) and k = 0.44 year-1) and females (L∞ = 65.56 cm (DW) and k = 0.26 year-1). Reproduction was determined by assessing maturity and reproductive stages. Sexual dimorphism was observed where females grew significantly larger than males. Males were determined mature when DW was greater than 38cm when claspers were shown to be fully calcified and vas deferens were coiled. Females were determined to reach maturity between 40 and 50 cm DW although a lack of smaller sized females prevented a more accurate estimate of first maturity. Females were observed pupping near term embryos ranging from 14.2 to 16 cm DW in mid-July and late September indicating possibilities of two litters per year. Large oocytes where observed in an ovary in a female with a uterus containing seven eggs with a mean mass of 2.80 g indicating that P. violacea exhibit vitellogenesis proceeding simultaneously with gestation. A clear seasonality for the reproductive cycle was not apparent however it seems parturition occurs in late spring and early fall when conditions are optimal for neonate survival. Data on the age, growth and reproduction of western north Atlantic populations of P. violacea will contribute to the lack of life history characteristics of this common bycatch species.

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Mazier, Hannah. "Role of Mitochondrial Dynamics and Cell Death in a Dihydrotestosterone-induced Rat Model of Polycystic Ovarian Syndrome, and its Regulation by Gonadotropin." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35572.

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Polycystic ovarian syndrome (PCOS) is a multi-factorial infertility disorder whose etiology and pathogenesis is not completely understood. Although there is an association between dysregulation of mitochondrial fission and fusion to cell death (apoptotic and autophagic) and the pathogenesis of various diseases, this had not been reported in the context of granulosa cell death, follicular growth arrest and PCOS. Follicle-stimulating hormone (FSH), a granulosa cell survival factor, is used during gonadotropin therapy to assist in follicular maturation and ovulation in women with PCOS. Whether FSH can modulate the possible dysregulation of granulosa cell mitochondrial dynamics and cell death in PCOS had not been elucidated. Chemerin is an adipokine that has been associated with PCOS and granulosa cell apoptosis in follicle cultures. Its role in cell death (apoptotic and autophagic) of primary granulosa cells had not been confirmed. In this thesis, we investigated the dysregulation of granulosa cell mitochondrial dynamics in PCOS pathogenesis by using an androgenized rat model, and its modulation by exogenous gonadotropin. The mechanisms involved in gonadotropic regulation were investigated using primary granulosa cells. Our data suggest that increased mitochondrial fission leads to early antral granulosa cell death, follicular growth arrest and anovulation in women with PCOS. FSH can regulate the phosphorylation of mitochondrial fission protein Drp1, which may lead to its suppression of mitochondrial fission and apoptosis in PCOS. Finally, chemerin had no effect on cell death in granulosa cell cultures. These findings provide a greater understanding of the processes involved in PCOS pathogenesis and the regulatory role of FSH in granulosa cells, laying the foundation for future study into the development of potential biomarkers and new treatment strategies.

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García, Morante Beatriz. "Moving towards an improved experimental model for reproduction of pneumonia induced by Mycoplasma hyopneumoniae." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/403816.

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La infecció per Mycoplasma hyopneumoniae està àmpliament estesa per la majoria de països productors de porcí. Malgrat la seva importància, encara hi ha punts rellevants que queden per resoldre; alguns d'ells referents a la complexa patogènesi de la infecció així com de la pneumònia que en resulta. Tot i que els models experimentals de M. hyopneumoniae són un bon punt de sortida per tractar aquestes qüestions, en aquest escenari s'observa una àmplia variabilitat tant en la reproductibilitat com en la prevalença i la gravetat de la pneumònia. Aquesta variabilitat és preocupant, per exemple, en el cas de voler complir amb els requisits d'eficàcia per a productes medicamentosos d’ús veterinari, especialment en el cas de les vacunes, ja que es demana una reducció significativa de les lesions pulmonars al comparar amb les de porcs no vacunats. Així doncs, un model experimental de M. hyopneumoniae validat i que asseguri la reproducció de pneumònia és d'interès. Aquesta tesi, de fet, es va plantejar per identificar i optimitzar les condicions experimentals que més poden influenciar el desenvolupament de pneumònia. A més, també s'hi avaluen paràmetres ante-mortem amb cert potencial per predir la prevalença i la gravetat de pneumònia. El primer estudi tenia com a objectiu identificar determinants per a la reproducció de pneumònia en condicions experimentals. Per aconseguir-ho, es va realitzar una revisió sistemàtica de la literatura seguit d'un anàlisi estadístic multivariant, denominat anàlisi recursiu de partició. Els resultats proporcionats constitueixen una primera visió de les condicions que donen suport al desenvolupament de pneumònia en entorns experimentals. Així, els models experimentals de M. hyopneumoniae que persegueixen la reproducció de pneumònia han d'avaluar les lesions pulmonars dins d'un període d'estudi de 8 setmanes i incloure inoculació de porcs lliures de M. hyopneumoniae, majors de 3.5 setmanes d'edat i co-infectats amb un altre patogen respiratori porcí. A més, dues condicions experimentals van ser avaluades de forma individual en els següents capítols. En el segon estudi es va comparar la pneumònia resultant de la inoculació artificial de M. hyopneumoniae mitjançant tres rutes diferents (endotraqueal, intranasal i aerosol). Com a resultat, la via endotraqueal va resultar ser la millor ruta d'inoculació per induir pneumònia en un període de 4 setmanes després de la inoculació. D'altra banda, en el tercer estudi es van usar diferents tècniques per al seguiment diari del creixement en cultiu de soques de M. hyopneumoniae de diferent patogenicitat. D'aquesta manera, aquestes tècniques es van poder avaluar com a possibles metodologies de titulació. Els resultats obtinguts demostren que aquelles tècniques que titulen els cultius a temps real es poden utilitzar per descriure el creixement in vitro de M. hyopneumoniae. Això ajuda a normalitzar els protocols de cultiu d'aquest patogen al laboratori, així com la producció d'inòculs per a aplicacions experimentals. L’últim estudi avaluà la capacitat de diferents paràmetres de la resposta immunitària humoral, tant a nivell local com sistèmic, per predir ante-mortem tant l'ocurrència com la gravetat de les lesions pulmonars associades a M. hyopneumoniae. En aquest cas, aquesta avaluació es va realitzar tant en porcs infectats experimental com naturalment. En general, els resultats indiquen que els paràmetres immunològics humorals es poden utilitzar per predir pneumònia sota un enfocament poblacional. Aquest capítol també descriu una resposta humoral sistèmica on predomina la subclasse IgG2 enfront el patogen.
The infection with Mycoplasma hyopneumoniae is widespread in almost all pig producing countries. Despite its importance, there are still relevant points to be resolved; some of them concern the complex pathogenesis of the infection as well as the resultant pneumonia outcome. For instance, M. hyopneumoniae experimental models are a good starting point for addressing some of these unresolved matters, although wide inconsistencies are seen in reproducibility, prevalence and severity of pneumonia. Among others, the latter is a major concern in the case of veterinary medicine product efficacy compliance, especially in vaccinology, where a significant reduction in the lung lesion score is required compared to non-vaccinated pigs. Thus, a validated M. hyopneumoniae experimental model enhancing severe pneumonia reproduction is of interest. Therefore, the present thesis was raised to provide insights into this matter through the identification and optimization of experimental conditions playing a role in pneumonia outcome. Furthermore, evaluation of ante-mortem parameters that would serve to foresee such outcome was also addressed. The first study aimed to identify determinants for the successful reproduction of pneumonia under experimental conditions. To reach this goal, a systematic review of the literature followed by a multivariable statistical analysis, named recursive partitioning, was done. The results obtained constitute the first insight into those conditions supporting pneumonia development under experimental settings. M. hyopneumoniae experimental models pursuing reproduction of severe pneumonia should assess lung lesions within a study period of 8 weeks and include inoculation of M. hyopneumoniae-free pigs older than 3.5 weeks of age and co-infected with another swine respiratory pathogen. Besides, other two experimental conditions were further investigated individually into the following chapters. In the second study, pneumonia outcome consequence of M. hyopneumoniae inoculation by means of three inoculation routes (endotracheal, intranasal and aerosol) was compared. As a result, the endotracheal was the most optimal route of inoculation to induce severe pneumonia within a period of 4 weeks after inoculation. On the other side, in the third study, the growth in culture of M. hyopneumoniae strains differing in pathogenicity was daily followed by different techniques, which were evaluated as putative titration methodologies. Results obtained proved that real-time culture titration assays can be used to describe the in vitro growth of M. hyopneumoniae and to standardise M. hyopneumoniae culture protocols in the laboratory as well as inoculum production for experimental applications. The last study evaluated different humoral immune response parameters, both at local and systemic levels, as ante-mortem predictors of occurrence and severity of lung lesions associated with M. hyopneumoniae. Such an evaluation was done either in experimentally and naturally infected pigs. Overall, results indicated that humoral immune parameters may be used as pneumonia predictors in a population-based approach. Moreover, a new insight into the humoral immune response against M. hyopneumoniae is provided by reporting a predominant IgG2 systemic response.

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41

Marques, dos Santos Miguel LuiÌs SimoÌƒes. "Models of the Fisher process based on reproductive value." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411112.

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42

Guggilla, Ramesh. "Genetic investigation of recurrent hydatidiform moles and reproductive loss." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119677.

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Hydatidiform mole (HM) is a form of gestational trophoblastic disease characterized by hydropic degeneration of chorionic villi of the placenta with or without embryo. My project is aimed at finding a new gene for recurrent HMs (RHMs). When I started this project there wasonly one gene, NLRP7, known to be causative of this condition, Mutations in a second gene, KHDC3L, in patients with RHMs were discovered by Parry et al. 2011. Genetic heterogeneity in the causation of RHMs is shown by our group and many others and is also evident from the absence of mutations in both NLRP7 and KHDC3L in some patients with RHMs. This suggests the possible role of other genes in the causation of RHMs. Exome sequencing was carried out on 18 patients with RHMs and no mutations in NLRP7 and KHDC3L. Analysis of the Exome sequencing data revealed NSVs in many genes. Of these, five candidate genes had two defective alleles in one patient, each. These variants were co-segregating with the phenotype and predicted to be damaging. Sequencing of these genes in more patients with recurrent HMs and reproductive wastage is underway in our laboratory and may help in finding new genes for molar pregnancies. After the identification of KHDC3L, I sequenced this gene in 97 patients with recurrent HMs and reproductive wastage who are negative for NLRP7. I found two frameshift deletion mutations, including one novel, in three patients with RHMs. I performed haplotype analysis using the SNPs surrounding one mutation and found that the haplotype is shared between patients of three ethnic groups, suggesting a strong founder effect for this mutation across populations. Co-localization experiments on lympoblastoid cell lines from normal subjects showed that that KHDC3L co-localizes with NLRP7 to the Golgi and microtubule organizingcenter.
La môle hydatidiforme (HM) est une forme de maladie trophoblastique gestationnelle caractérisée par une dégénérescence hydropique des villosités choriales du placenta avec ou sans embryon. Mon projet visait à identifier un nouveau gène responsable des môles hydatidiformes récurrentes (MHR). Quand j'ai commencé ce projet, un seul gène, NLRP7, était connu pour être responsable de cette condition. Des mutations dans un second gène, KHDC3L, ont été ensuite découvertes par Parry et al. 2011 chez des patientes atteintes de MHR. L'hétérogénéité génétique dans l'étiologie des MHR a été démontrée par plusieurs équipes, y compris la notre, et ressort également de l'absence de mutations dans les deux gènes NLRP7 et KHDC3L chez certaines patientes atteintes de MHR. Ceci suggère l'implication d'autres gènes qui causent les MHR. Le séquençage des exomes a été réalisé sur 18 patientes atteintes de MHR mais ne portant aucune des mutations dans NLRP7 ou KHDC3L. L'analyse des données de séquençage des exomes a révélé la présence de variants non-synonymes dans de nombreux gènes. Parmi ceux-ci, cinq gènes candidats présentant chacun deux allèles défectueux. Ces variants co-ségrégeaient avec le phénotype anormal et sont prédits dommageables. Le séquençage de ces gènes chez les patientes atteintes de MHR et d'autres formes d'echecs de reproduction est en cours dans notre laboratoire et pourrait aider à identifier de nouveaux gènes responsables des grossesses môlaires. Après l'identification du gène KHDC3L, j'ai séquencé ce dernier chez 97 patientes atteintes de MHR et d'autres formes d'echec de la reproduction mais ne présentant pas de mutations au niveau du gène NLRP7. Deux délétions dont une nouvelle affectant le cadre de lecture de ce gène ont été identifiées chez trois patientes atteintes de MHR. L'analyse des haplotypes par SNP autour de la mutation commune du KHDC3L a révélé le meme haplotype chez les trois patientes de differentes ethnies suggérant ainsi un effet fondateur important de cette mutation dans différentes populations. Des expériences de co-localisation sur des lignées cellulaires lympoblastoides chez des sujets normaux ont montré que KHDC3L co-localise avec NLRP7 au niveau de l'appareil de Golgi et le centre organisateur des microtubules ou centrosome.

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43

Adamec, Vaclav. "The Effect of Maternal and Fetal Inbreeding on Dystocia, Calf Survival, Days to First Service and Non-Return Performance in U.S. Dairy Cattle." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/25999.

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Intensive selection for increased milk production over many generations has led to growing genetic similarity and increased relationships in dairy population. In the current study, inbreeding depression was estimated for number of days to first service, summit milk, conception by 70 days non-return, and calving rate with a linear mixed model (LMM) approach and for calving difficulty, calf mortality with a Bayesian threshold model (BTM) for categorical traits. Effectiveness of classical and unknown parentage group procedures to estimate inbreeding coefficients was evaluated depending on completeness of a 5-generation pedigree. A novel method derived from the classical formula to estimate inbreeding was utilized to evaluate completeness of pedigrees. Two different estimates of maternal inbreeding were fitted in separate models as a linear covariate in combined LMM analyses (Holstein registered and grade cows and Jersey cows) or separate analyses (registered Holstein cows) by parity (1-4) with fetal inbreeding. Impact of inbreeding type, model, data structure, and treatment of herd-year-season (HYS) on magnitude and size of inbreeding depression were assessed. Grade Holstein datasets were sampled and analyzed by percentage of pedigree present (0-30%, 30-70% and 70-100%). BTM analyses (sire-mgs) were performed using Gibbs sampling for parities 1, 2 and 3 fitting maternal inbreeding only. In LMM analyses of grade data, the least pedigree and diagonal A matrix performed the worst. Significant inbreeding effects were obtained in most traits in cows of parity 1. Fetal inbreeding depression was mostly lower than that from maternal inbreeding. Inbreeding depression in binary traits was the most difficult to evaluate. Analyses with non-additive effects included in LMM, for data by inbreeding level and by age group should be preferred to estimate inbreeding depression. In BTM inbreeding effects were strongly related to dam parity and calf sex. Largest effects were obtained from parity 1 cows giving birth to male calves (0.417% and 0.252% for dystocia and calf mortality) and then births to female calves (0.300% and 0.203% for dystocia and calf mortality). Female calves from mature cows were the least affected (0.131% and 0.005% for dystocia and calf mortality). Data structure was found to be a very important factor to attainment of convergence in distribution.
Ph. D.

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44

吳樹強 and S. K. Ng. "Real estate development opportunities in Shanghai: a reproduction of the Hong Kong model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B3125701X.

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Ng, S. K. "Real estate development opportunities in Shanghai : a reproduction of the Hong Kong model /." Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25939452.

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46

Piffaretti, Joséphine. "Différenciation génétique et écologique au sein des populations du puceron Brachycaudus helichrysi (Hemiptera Aphididae) : mise en évidence de deux espèces soeurs au cycles de vie contrastés." Thesis, Montpellier, SupAgro, 2012. http://www.theses.fr/2012NSAM0023/document.

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Brachycaudus helichrysi est un puceron ravageur des cultures qui inflige de sérieux dégâts à ses hôtes primaires (arbres fruitiers du genre Prunus) ainsi qu'à plusieurs herbacées cultivées correspondant à ses hôtes secondaires (par exemple les tournesols et les chrysanthèmes).L'étude phylogéographique de l'espèce basée sur un échantillonnage mondial, montre que B. helichrysi rassemble deux taxa appelés B. helichrysi H1 et H2. Cette étude, basée sur plusieurs marqueurs génétiques (mitochondriaux, nucléaire et bactériens), révèle une divergence génétique de l'ordre de celle observée entre espèce du genre Brachycaudus. Ceci suggère que B. helichrysi H1 et H2 sont deux espèces sœurs. Comme H1 et H2 sont morphologiquement indistinguables, nous avons mis au point un test de discrimination génétique par PCR-RFLP.L'analyse des génotypes (14 loci microsatellites) combinés aux données écologiques suggère que ces deux espèces sœurs ont des histoires évolutives différentes. Le cycle de vie de B. helichrysi H1 correspondrait à la parthénogenèse cyclique, utilisant les pruniers comme hôte primaire. Nous avons montré qu'il existe chez H1 des clusters génétiques structurés géographiquement. Au contraire, B. helichrysi H2 rassemble principalement des lignées clonales polyphages, persistantes et largement distribuées dans le monde (i.e. superclones), ainsi qu'une lignée sexuée, probablement hétéroécique, qui a été trouvée sur pêchers en Inde. Les individus des deux espèces colonisent fréquemment une même plante herbacée, composant ainsi des colonies « mixtes ». Cette étude apportera un éclairage sur comment l'évolution des cycles de vie, en particulier la perte de la reproduction sexuée, a pu jouer un rôle dans les processus de spéciation au sein du complexe B. helichrysi
Brachycaudus helichrysi is a worldwide polyphagous aphid pest that seriously damages its primary hosts (Prunus spp.) and the various cultivated plants among its secondary hosts (e.g. sunflower, chrysanthemums).In a phylogeographic study based on a worldwide sampling, I have shown that this species is actually an amalgamation of two sibling taxa called B. helichrysi H1 and B. helichrysi H2. This study based on mitochondrial, nuclear and Buchnera aphidicola (the primary symbiont of aphids) DNA markers revealed that these two taxa display levels of genetic divergence as great as those generally found between sister species in the Brachycaudus genus, suggesting that they actually correspond to two distinct sibling species. As these two species are morphologically indistinguishable, we developed a PCR-RFLP test to genetically discriminate them.Further investigations, based on microsatellites data combined with ecological information suggest that these two species have two very different evolutionary histories. Brachycaudus helichrysi H1 exhibits a typical signature of cyclical parthenogenesis, using plum trees during the sexual phase, and we demonstrate the existence of distinct geographic genetic clusters within this species. By contrast B. helichrysi H2 comprises two types of lineages. First, it gathers several persistent obligate clonal lineages distributed worldwide (i.e. superclones) and highly polyphagous, and second, we reveal the existence of a cyclical parthenogenetic H2 lineage that uses peach trees as primary hosts and has so far only been found in India. All B. helichrysi lineages of H1 and H2 co-occurred in mixed colonies on herbaceous hosts all around the world.This study will shed light on how life cycle evolution, especially the loss of sexual reproduction, could explain the ongoing speciation process in the B. helichrysi species complex

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Nygren, Kristiina. "Evolutionary Consequences of Reproductive Strategies : Testing Theory on Sex and Reproductive Gene Evolution in the Fungal Model Neurospora." Doctoral thesis, Uppsala universitet, Evolutionsbiologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-152953.

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In this thesis, I used the filamentous ascomycete genus Neurospora as a model to test theoretical predictions on the evolutionary consequences of different reproductive strategies and reproductive gene evolution. The genus Neurospora contains taxa representing a diversity of reproductive strategies, and here I constructed a phylogeny by which I was able to show that several independent transitions in reproductive mode have occurred in the evolutionary history of the genus. This feature makes Neurospora a suitable model for the evolution of reproductive modes. Molecular evolutionary analysis of housekeeping genes revealed an accelerated protein evolution in the highly inbreeding homothallic taxa, in accordance with theory predictions of lower efficiency of selection in asexual and highly inbreeding taxa. Furthermore, self-sterile (heterothallic) taxa capable of asexual propagation was found to be associated with a three-fold higher neutral substitution rate, indicative of a higher mutation accumulation due to elevated number of cell divisions per unit time in these taxa. Further, I have shown a general pattern of rapid evolution of genes involved in reproduction in Neurospora, thus extending the pattern of general high divergence of reproductive genes previously well known in animals, to fungi. Two rapidly evolving reproductive genes: the pheromone receptor genes pre-1 and pre-2 involved in mate recognition were studied in detail. For the gene pre-1 the rapid divergence was found to be driven by positive selection in both heterothallic and homothallic taxa. The rapid divergence of the pheromone receptor gene pre-2 cannot be explained by positive selection and for this gene a subtle differences in evolutionary constraints between heterothallic and homothallic taxa were found. The general similarity in evolutionary constraints of pre-genes in taxa of both mating-systems indicates that these genes serve other functions beside mate recognition.

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Zhang, Jinwen. "The mouse oocyte as a model in reproductive toxicology studies /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-163-0/.

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Rasheed, Shaker M. "A reaction-diffusion model for inter-species competition and intra-species cooperation." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13545/.

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This thesis deals with a two component reaction-diffusion system (RDS) for competing and cooperating species. We have analyse in detail the stability and bifurcation structure of equilibrium solutions of this system, a natural extension of the Lotka-Volterra system. We find seven topologically different regions separated by bifurcation boundaries depending on the number and stability of equilibrium solutions, with four regions in which the solutions are similar to those in the Lotka-Volterra system. We study RDS in the small parameter of the range $0< \lambda \ll 1 $ (fast diffusion and slow reaction), and in a few cases we assume $\lambda=O(1)$. We consider three types of initial conditions, and we find three types of travelling wave solutions using numerical and asymptotic methods. However, neither numerical nor asymptotic methods were able to find a particular travelling wave solution which connects a coexistence state say, $(u_0,w_0)$ to an extinction state $(0,0)$ when $0< \lambda \ll 1 $. This type can be found when the reaction-diffusion system satisfy the symmetry property and $\lambda=1$.

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Großekathöfer, Ulf [Verfasser]. "Ordered Means Models for recognition, reproduction, and organization of interaction time series / Ulf Großekathöfer." Bielefeld : Universitätsbibliothek Bielefeld, 2013. http://d-nb.info/1051076978/34.

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Dissertations / Theses on the topic 'Modes of reproduction'

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