Tesi sul tema "Reproduction (biologie) – Évolution"
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Angelier, Frédéric. "Age et reproduction chez les oiseaux marins : mécanismes hormonaux impliqués dans les décisions de reproduction". Poitiers, 2006. http://www.theses.fr/2006POIT2328.
Breeding success increases with age in many organisms, but the physiological mechanisms underlying this pattern are poorly known. The aim of this dissertation is to explore the influence of age on hormonal mechanisms involved in the regulation of parental behaviour, allostasis and stress response (corticosterone and prolactin) in seabirds. The use of ongoing long-term mark-recapture programme allowed us to show that age and especially breeding experience influence baseline hormones levels and the sensitivity to stressors. We were able to describe the first hormonal correlates of senescence. We showed the role of corticosterone, which in interaction with body condition, mediates foraging decisions and allocations processes. Our data strongly suggest that variations in baseline corticosterone levels and the ability to maintain a threshold levels of prolactin during a stressful situation may be an important physiological mechanism involved in the improvement of reproductive performance with advancing age. These findings are discussed in the light of current the evolutionary theories addressing the effect of age and experience on reproductive success
Leturque, Henri. "Evolution du sexe ratio et de la dispersion en populations structurées". Montpellier 2, 2002. http://www.theses.fr/2002MON20177.
Haudry, Annabelle. "Influence de la domestication et du système de reproduction sur la diversité et l'évolution des gènes chez les Triticeae". Montpellier 2, 2007. http://www.theses.fr/2007MON20244.
Abu, Awad Diala. "Death and sterility with a side of evolutionary suicide : the interplay of deleterious mutations and population size and the evolution of self-fertilisation". Electronic Thesis or Diss., Lille 1, 2014. http://www.theses.fr/2014LIL10134.
As the ultimate source of genetic variation, mutation has the inconvenience of introducing deleterious mutations. These mutations shape the evolution of species, from genetic mechanisms on the cellular level to reproductive systems, which lessen their effects on fitness. In this thesis we explore how these mutations influence population size by allowing the interaction between population size and selection, which has been little explored in conventional population genetics models. In a deterministic context with a single locus, germ-line and somatic mutations influence population size and the mutation load, both which depend on the timing of the expression of these mutations. Multi-locus individual based models show that population viability depends on the demographic properties and on the rate of introduction and impact of mutations. Though self-fertilisation generally increases population viability, strictly self-fertilising populations go extinct due to mutational meltdown when mutations are of small effect. When selfing is allowed to evolve from an outcrossing reproductive regime, there are cases of evolutionary suicide where strict selfing evolves and leads to extinction. We predict that the genetic properties of populations may not be a consequence but a cause of population size. We have emphasized the importance of taking the demographic consequences of deleterious mutations into account when studying the evolution of populations, as in the case of the evolution of self-fertilisation where the previously undetected evolutionary suicide was observed. This result may explain the observed higher extinction rates in selfing compared to outcrossing species
Glémin, Sylvain. "Dépression de consanguinité, systèmes de reproduction et biologie de la conservation. Approches théoriques et expérimentales chez Brassica insularis Moris". Montpellier 2, 2002. http://www.theses.fr/2002MON20171.
Thériault, Véronique. "Évolution des tactiques alternatives chez l'omble de fontaine. Patrons de reproduction, héritabilité et pêche sélective". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24870/24870.pdf.
The central objective of this thesis was to assess the genetic basis of alternative life-history tactics in brook charr, Salvelinus fontinalis. Anadromy, defined as migration to sea before returning to freshwater to spawn, and residency, the completion of the entire life-cycle in freshwater, are two tactics commonly found in sympatry in salmonids. These two life-history forms are considered here as alternative tactics within a conditional strategy and are studied according to the threshold model of quantitative genetics. First, molecular markers and parentage analysis revealed that reproduction frequently occurred between the two forms, and was mediated by the resident males. Moreover, individual reproductive success was linked to body size in females, but not in males, which suggest that smaller males make use of the alternative sneaker reproductive tactic. Second, sib-reconstruction methods coupled to an “animal model” allowed the estimation of a significant heritability for the life-history tactic (between 0.53 and 0.56) and a significant genetic correlation between body size and tactic (-0.52 and -0.61), suggesting a joint evolution of these two traits. Finally, the evolutionary consequences of sportfishery on the evolution of anadromy and residency were assessed with the use of an eco-genetic model. After a hundred years of fishing-induced selection directed toward anadromous fish, the migration reaction norms shifted, resulting in a decrease in the probability of migrating with increasing harvest rate. This change was accompanied by a higher mean age at migration. The proportion of fish adopting the anadromous tactic decreased in the population as harvest rate increased, as did the absolute number of fish found in saltwater. These changes resulted in a lower mean age and size at maturity. This thesis contributes to our understanding of the determinism of alternative phenotypes and stands out because of its realization under completely natural conditions. By highlighting the genetic basis of anadromy and residency, this work suggests that an evolutionary response is expected in face of anthropogenic or natural selective forces, and such consequences are presented through an innovative modeling approach.
Perdereau, Elfie. "Biologie de l'invasion d'un termite américain en France : évolution de l'organisation sociale et conséquences sur le succès invasif". Thesis, Tours, 2010. http://www.theses.fr/2010TOUR4024/document.
The increasing of ecological and economical problems linked to biological invasion phenomenon necessitate a better understanding of mechanisms allowing an invasive success. In social insects, studies are mainly focused on social Hymenoptera, and has demonstrated that social organization of introduced populations presented particular characters allowing their invasive success. The principal objective of my PhD is to characterize the social organization of the introduced populations in Isoptera through the study of the American termite Reticulitermes flavipes introduced in France. The overall of results reveals (i) strong variations of social organization between native and introduced populations presenting a extreme form of neoteny and a strong capacity to colonial fusion; (ii) these variations seem to have evolved after its introduction in France, and (iii) to allow the establishment and expansion of R. flavipes in France, similarly to unicoloniality and polygyny observed in the social invasive Hymenoptera. The possible evolutionary origins of the observed variations between native and introduced populations of R. flavipes are discussed
Picq, Sandrine. "Diversité et évolution chez Vitis vinfera L. de traits impliqués dans le syndrome de domestication et dans la biologie de la reproduction". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20001.
Domestication is a complex evolutionary process in which, human selection pressures lead to great morphological and physiological changes that allow to differentiate domesticated species from their wild ancestors. Recent archaeobotanical, genetic and genomic studies of various annual crops such as maize (Zea mays L.), rice (Oryza sativa L.) and tomato (Solanum lycopersicum L.) have significantly advanced our understanding of plant domestication. However, the domestication of perennial plants, particularly fruit trees, remains poorly documented compared to the domestication of annual crop plants.In this framework, this work aims to contribute to the understanding of the domestication process of the emblematic perennial plant, the grapevine (Vitis vinifera L.) through the study of diversity and evolution of two major traits of the domestication syndrome: the seed shape and the reproductive system. Our work on seed shape based on the method of the elliptic Fourier transforms revealed significant relationships between seed shape, the taxonomic status (wild – domesticated), the geographic origin of cultivars and their parentage relationships, corroborating former results from genetic analysis. On the other hand, seed shape changes occurred during domestication seem to be linked to the increase of the berry size as the consequence of major human selection pressures. Regarding the transition from diecy to hermaphroditism to diecy operated during domestication, the analysis of sequence polymorphism in the sex locus revealed that domesticated grapevine would be the descendant of wild male individuals able to produce berries. The pattern of diversity of these sequences supports the hypothesis of the occurrence of a major domestication event in the Near East and testify of introgressions of Western European cultivars by local wild grapes
Ganem, Guila. "Commensalisme, fonction corticosurrénalienne et évolution chromosomique chez la souris domestique". Montpellier 2, 1991. http://www.theses.fr/1991MON20053.
Gervais, Camille. "Evolution de l'auto-incompatibilité : modélisation des conditions de maintien et de diversification en populations finies". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10180/document.
Self-incompatibility is a widespread genetic system, which enables hermaphrodite plants to avoid self-fertilization and mating with close relatives. It is based on the pistil's capacity to recognize and reject pollen when they express cognate specificities. Specificities are encoded by alleles at the self-incompatibility gene complex (known as the S-locus), composed of two linked genes, one expressed in pollen and the other expressed in pistils. During my PhD, I studied the maintenance and evolution of self-incompatibility from a theoretical standpoint, using a modeling approach. The first part of my thesis examined the co-evolution of self-incompatibility and inbreeding depression in finite populations, focusing on the conditions for maintenance of self-incompatibility when self-compatible mutants were repeatedly introduced in the population by recurring mutations. Our results showed that the maintenance of self-incompatibility is associated with high inbreeding depression, and is facilitated by high rates of self-pollination. The second part of my thesis explored the conditions for evolution of novel self-incompatibility alleles (S alleles), which we have studied both analytically in infinite populations and in finite populations via computer simulations. Our results showed that the conditions for diversification at the S locus are much less stringent in finite than in infinite populations, and that there is more diversification at this locus when few S alleles are present in the population
Grosmaire, Manon. "Caractérisation du mode de reproduction pseudogame chez l’espèce de nématode Mesorhabditis belari". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1151/document.
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
Desmarais, Eric. "Phylogénies intraspécifiques et histoire évolutive des populations de souris Mus spretus Lataste : analyse des lignées matriarcales par séquençage nucléotidique de l'ADN mitochondrial". Montpellier 2, 1989. http://www.theses.fr/1989MON20208.
Lesaffre, Thomas. "Contribution à une théorie physiologique et génétique de l’évolution végétale : fardeau génétique, systèmes de reproduction et évolution du taux de mutation dans les populations structurées en classes". Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUR014.
In Angiosperms, there exists a strong association between life-history and mating system. Indeed, most predominantly selfing species are annual while the majority of perennials are outcrossers. This association is the starting point of the work presented in this thesis. In the first chapter, I study the joint evolution of lifespan and selfing assuming that inbreeding depression affects survival between flowering seasons and is fixed by a parameter. Under these assumptions, lifetime inbreeding depression increases as lifespan increases therefore preventing the evolution of self-fertilisation in a wider parameter range. When it occurs, it induces the evolution of shorter lifespans. These results are in agreement with the empirically observed pattern. In chapter two, I relax the assumption that inbreeding depression is fixed by a parameter, by assuming an explicit genetic basis. Far from generating higher inbreeding depression in more long-lived species, deleterious mutations affecting survival result in a decrease of inbreeding depression with longevity at mutation-selection equilibrium. Yet, increased inbreeding depression is empirically observed in long-lived species. In the following chapters, I explore two hypotheses to explain this increase. In chapter two, I study the more general idea that variations in the fitness effects of mutations with longevity, of which mutations affecting survival are a mere special case, may generate increased inbreeding depression in longer-lived species. In chapter three, I model the consequences of inheritable somatic mutations accumulating during growth for the evolution of the mutation rate and the resulting inbreeding depression in plants. As for chapter four, it is devoted to a theoretical evaluation of indirect inbreeding depression estimation methods. I end this manuscrit by proposing leads and ideas for the development of a physiological and genetic theory of plant evolution
Abu, Awad Diala. "Death and sterility with a side of evolutionary suicide : the interplay of deleterious mutations and population size and the evolution of self-fertilisation". Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10134/document.
As the ultimate source of genetic variation, mutation has the inconvenience of introducing deleterious mutations. These mutations shape the evolution of species, from genetic mechanisms on the cellular level to reproductive systems, which lessen their effects on fitness. In this thesis we explore how these mutations influence population size by allowing the interaction between population size and selection, which has been little explored in conventional population genetics models. In a deterministic context with a single locus, germ-line and somatic mutations influence population size and the mutation load, both which depend on the timing of the expression of these mutations. Multi-locus individual based models show that population viability depends on the demographic properties and on the rate of introduction and impact of mutations. Though self-fertilisation generally increases population viability, strictly self-fertilising populations go extinct due to mutational meltdown when mutations are of small effect. When selfing is allowed to evolve from an outcrossing reproductive regime, there are cases of evolutionary suicide where strict selfing evolves and leads to extinction. We predict that the genetic properties of populations may not be a consequence but a cause of population size. We have emphasized the importance of taking the demographic consequences of deleterious mutations into account when studying the evolution of populations, as in the case of the evolution of self-fertilisation where the previously undetected evolutionary suicide was observed. This result may explain the observed higher extinction rates in selfing compared to outcrossing species
Cao, Vien. "Contribution à l'étude des péridiniens d'eau douce : Isolement de clones, culture, nutrition. Quelques aspects inconnus ou peu connus de la biologie de ces algues". Paris 7, 1987. http://www.theses.fr/1987PA077098.
Reichel, Katja. "Effets de la reproduction partiellement asexuée sur la dynamique des fréquences génotypiques en populations majoritairement diploïdes". Thesis, Rennes, Agrocampus Ouest, 2015. http://www.theses.fr/2015NSARC123/document.
Reproductive systems determine how genetic material is passed from one generation to the next, making them an important factor for evolution. Organisms that combine sexual and asexual/clonal reproduction are very widespread [… yet] the effects of their reproductive system on their evolution are still controversial and poorly understood.The aim of this thesis was to model the dynamics of genotype frequencies under combined sexual/clonal reproduction in dominantly diploid life cycles [. … A] state and time discrete Markov chain model served as the mathematical basis to describe [their] changes […] through time.The results demonstrate that partial clonality may indeed change the dynamics of genomic diversity compared to either exclusively sexual or exclusively clonal populations. […] Time has a crucial role in partially clonal populations and needs to be taken into account in any analysis of their genomic diversity.This thesis provides recommendations for data collection and a null hypothesis for the interpretation of population genetic/genomic data […]. Moreover, it includes new methods for the analysis of genotype-based population genetic Markov chain models. These results have a high potential relevance in several areas, ranging from basic research […] to applications in agriculture […], fisheries […] and nature conservation […]
Tobias, Santos Vitória. "A Transcriptome-Level Comparison of Independently Evolved Non-Embryonic Development in Different Species of Styelidae (Tunicata)". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS401.pdf.
Tunicates (Chordata) are the closest relative to vertebrates able to undergo whole-body regeneration (WBR) upon severe injury or as part of their asexual life cycle. In different tunicate species, WBR starts from various non-homologous epithelia or mesenchymal cells, which either home adult stem cells or undergo de/transdifferentiation. The cell dynamics and the molecular players behind WBR are still elusive. To better understand differences and commonalities between independently evolved WBRs, I focused on the family of Styelidae, in which I selected two tunicate laboratory-reared species that independently evolved the capacity of WBR: Botryllus schlosseri and Polyandrocarpa zorritensis. Taking advantage of our previous morphological characterization of P. zorritensis WBR, I adapted a live-staining technique that allowed me to obtain the transcriptomic profile of seven informative stages of WBR in this species. Differential gene expression analysis revealed clusters of genes associated with each stage, from WBR initiation to the onset of morphogenesis. I’m now comparing these results with published and in-house RNAseq datasets of WBR in other species of tunicate (B. schlosseri, B. leachii, and P. misakiensis) taking advantage of available transcriptomic data as well as high quality genome data recently obtained by our team. This started to lead to the identification of orthologous genes sharing a dynamic expression during convergently acquired WBR. Further exploration of the expression pattern of these genes across species will allow us to identify common and different mechanisms underlying the plastic evolution of WBR in chordates
Petit, Daniel. "Contribution à l'étude de l'évolution des Carduées et Lactucées (Composées)". Montpellier 2, 1990. http://www.theses.fr/1990MON20127.
Bienvenu, François. "Random graphs in evolution". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS180.
This thesis consists of five independent research projects, related either to random graphs or to evolutionary biology - and most often to both. Chapters 2 and 3 introduce two random graphs that are obtained as the stationary distributions of graph-valued Markov chains. The first of these, which we term the split-and-drift random graph, aims to describe the structure and dynamics of interbreeding-potential networks; the second one is a random forest that was inspired by the celebrated Moran model of population genetics. Chapter 4 is devoted to the study of a new class of phylogenetic networks that we term ranked tree-child networks, or RTCNs for short. These networks correspond to a subclass of tree-child networks that are endowed with an additional structure ensuring compatibility with a time-embedded evolutionary process, and are designed to model reticulated phylogenies. We focus on the enumeration and sampling of RTCNs before turning to the structural properties of large uniform RTCNs. In Chapter 5, we prove a general result about oriented percolation in randomly oriented graphs: the positive association of the percolation cluster. Finally, in Chapter 6 we focus on a widely used statistic of populations: the mean age at which parents give birth. We point out several problems with one of the most widely used way to compute it, and provide an alternative measure
Aubry, Lise Myriam. "Influence du recrutement sur les variations des paramètres démographiques avec l'âge et la vitesse de sénescence chez la mouette tridactyle, Rissa tridactyla". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/1581/.
I used a 30-year study of long-lived seabirds (black-legged Kittiwakes) that breed in Brittany to study the evolution of trade-offs between early-life breeding decisions, future reproduction, and survival. I first found that recruitment age and habitat selection were intimately linked. Recruitment age further influenced breeding success and survival trajectories. Furthermore, sources of observed (reproductive covariates, experience) and unobserved heterogeneity (frailty) explained substantial amounts of variability in breeding success and survival. Overall, intermediate age recruits (age 5) seemed to maintain high breeding success over life and minimized senescence in survival compared to other recruits. Even though individual fitness showed that earlier recruitment was the most beneficial recruitment strategy, the costs associated to delayed recruitment seemed minimal
Coste, Christophe. "The costs of reproduction in evolutionary demography : an application of Multitrait Population Projection Matrix models". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC259/document.
Costs of reproduction are pervasive in life history theory. Through this constraint, the reproductive effort of an organism at a given time negatively affects its later survival and fertility. For life historians, they correspond mostly to a physiological trade-off that stems from an allocative process, occurring at each time-step, at the level of the individual. For evolutionary demographers, they are essentially about genetic trade-offs, arising from a genetic variance in a pleiotropic gene acting antagonistically on early-age and late-age fitness components. The study, from an evolutionary demographic standpoint, of these mechanisms and of the relative, cross and joint effects of physiological and genetic costs, is the aim of this thesis. The close examination of Williams (1966)’s original definition of the physiological costs of reproduction led us to produce a theoretical design of their apparatus that accounts for both their mechanistic and evolutionary mechanisms. This design allowed us to make predictions with regards to the strength of costs of reproduction for various positions of organisms on three life-history spectra: slow-fast, income-capital breeders and quality-quantity. From Stearns (1989b)’s tryptic architecture of life history trade-offs –that divides their structure into the genotypic level, the intermediate structure and the phenotypic level – we devised a general framework, which models the possible cohabitation of both physiological and genetic costs. From this, we inferred differing detectability patterns of both types of costs according to the environmental conditions, their variance and individual stochasticity. We could also establish that both costs buffer environmental variations, but with varying time windows of effect. Their dissimilarity emerges also from the differences between mathematical projection models specific to each cost. A new family of evolutionary models is therefore required to implement both physiological and genetic trade-offs. We then describe the vector-based construction method for such a model which we call Multitrait Population Projection Matrix (MPPM) and which allows incorporating both types of costs by embedding them as traits into the matrix. We extend the classical sensitivity analysis techniques of evolutionary demography to MPPMs. Most importantly, we present a new analysis tool for both life history and evolutionary demography: the Trait Level Analysis. It consists in comparing pairs of models that share the same asymptotic properties. Such ergodic equivalent matrices are produced by folding, an operation that consists in reducing the number of traits of a multi-trait model, by averaging transitions for the traits folded upon, whilst still preserving the asymptotic flows. The Trait Level Analysis therefore allows, for example, to measure the evolutionary importance of costs of reproduction by comparing models incorporating them with folded versions of these models from which the costs are absent. Using classical and new methods to compute fitness moments – selection gradient, variance in reproductive success, environmental variance - in models with and without the costs, we can show their effects on various demographic and evolutionary measures. We reveal, in this way, the combined effects of genetic and physiological costs on the vital rates of an age-structured population. We also demonstrate how physiological costs affect both components of effective selection, as they flatten the slope of selection gradients and increase the effective size of a population. Finally, we show how their buffering of environmental and demographic variance confer greater resilience to populations experiencing physiological costs of reproduction
Kerdal, Zakaria. "Biologie évolutive de la reproduction chez les canidae : recherche appliquée sur le fennec (Fennecus zerda)". Paris, Muséum national d'histoire naturelle, 1996. http://www.theses.fr/1996MNHN0023.
Paradis, Emmanuel. "Dynamique des populations du campagnol provençal (Microtus duodecimcostatus) : démographie, hétérogénéité spatiale et facteurs évolutifs". Montpellier 2, 1993. http://www.theses.fr/1993MON20119.
Foucaud, Julien. "Biologie évolutive d'une fourmi envahissante à la sexualité insolite, Wasmannia auropunctata". École nationale supérieure agronomique (Montpellier), 2007. http://www.theses.fr/2007ENSA0032.
Foray, Vincent. "La plasticité phénotypique en réponse à la variabilité environnementale : de la norme de réaction aux mécanismes physiologiques". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10299.
Phenotypic plasticity, i.e. the ability of a genotype to express several phenotypes depending on environmental conditions, represents an important source of phenotypic variability and so plays a major role in evolution. In a variable environment, generalist strategies, able to maintain a stable value of fitness over a wide range of environmental conditions, thanks to a greater plasticity of underlying traits, should be favored. The analysis of reaction norms of physiological traits and traits related to fitness as a function of temperature reveals in the parasitoid Venturia canescens that (i) thermal variability of the habitat determines the shape of reaction norms, according to the trade-off between generalist and specialist strategies, (ii) differences between generalist and specialist individuals are maintained face to rapid fluctuations in temperature that mimic natural conditions and (iii) individuals experiencing greater variability in their thermal habitat have a greater capacity for cold acclimation. These results indicate the existence of two different strategies in V. canescens and therefore a thermal niche differentiation, allowing their coexistence in a heterogeneous environment
Laugier, Thierry. "Ecologie de deux phanérogames marines sympatriques "Zostera marina L. " et "Zostera noltii Hornem. " dans l'étang de Thau (Hérault, France)". Montpellier 2, 1998. http://www.theses.fr/1998MON20170.
Kuhn, Alexandre. "Origin and evolution of social hybridogenesis in Cataglyphis ants: Origine et évolution de l'hybridogenèse sociale chez les fourmis Cataglyphis". Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/287547.
L’hybridation et l’introgression génétique jouent un rôle majeur dans l’adaptation et ladiversification des espèces. Chez les fourmis du désert du genre Cataglyphis, certaines espècesont évolué une stratégie de reproduction remarquable, appelée hybridogenèse sociale, reposantsur l’hybridation systématique entre deux lignées génétiquement distinctes. Les ouvrières nonreproductricessont issues de l’accouplement entre des partenaires de lignées distinctes ;enrevanche, les reines et les mâles sont produits de façon asexuée par parthénogenèse. Lesouvrières sont donc toutes des hybrides des deux lignées, alors que les individus reproducteurssont de pure-lignées. Bien que plusieurs études aient analysé les stratégies de reproduction desfourmis Cataglyphis, l’origine et le fonctionnement de l’hybridogenèse sociale au sein du genrerestent obscurs.Dans cette thèse, trois aspects associés au maintien de ce système ont premièrement étéétudiés en prenant la fourmi Cataglyphis mauritanica comme modèle. (i) La forte associationentre génotype et caste des femelles est lié à une forte influence génétique sur le déterminismede la caste. Néanmoins, une certaine plasticité phénotypique est maintenue dans les génomeshybrides et pure-lignée mais elle ne s’exprime pas en conditions naturelles. (ii) L’analysegénétique d’une population hybridogène de C. mauritanica montre que les deux lignées sontéquifréquentes. De plus, une dispersion limitée des reines ainsi que leur production parparthénogenèse mènent à la formation d’une mosaïque de patches clonaux. A l’inverse, lesmâles dispersent d’un patch à l’autre assurant les accouplements interlignées. (iii) Afin dedéterminer si les accouplements intralignées participent à la production des reines, des donnéesgénétiques ont été simulées sous différents taux de reproduction sexuée et asexuée. Les résultatsmontrent que la diversité génétique au sein de chaque lignée correspond à une faible fréquencede reproduction sexuée, bien que qu’un scénario avec 100% de clonalité ne puisse être écarté.Ensuite, l’origine évolutive de l’hybridogenèse sociale chez les Cataglyphis a étéanalysée. L’étude des systèmes reproducteurs de 11 espèces de Cataglyphis a permis ladécouverte de 5 nouveaux systèmes hybridogènes. Des analyses phylogénétiques, basées surces espèces et sur toutes les espèces de Cataglyphis pour lesquels le système reproducteur a étéprécédemment étudié, indiquent que ce système reproducteur aurait évolué plusieurs foisindépendamment au sein du genre Cataglyphis.En conclusion, les résultats de cette thèse soulignent les singularités d’un systèmehybridogène associé à la parthénogénèse des reines, qui a pu faciliter l’évolution répétée delignées dépendantes chez les fourmis Cataglyphis.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Gagnon, Marie-Claude. "Conflit sexuel chez le patineur Gerris Gillettei". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28168/28168.pdf.
Lahiani, Emna. "Dynamique évolutive de la gynodioécie chez Silene nutans et conditions de son maintien en populations". Electronic Thesis or Diss., Lille 1, 2013. http://www.theses.fr/2013LIL10045.
Gynodioecy - the coexistence of female and hermaphrodite individuals, is one of the most common systems after hermaphroditism in angiosperms. The maintenance and evolution of gynodioecy intrigued many evolutionary biologists. The aim of my thesis was to determine the evolutionary forces involved in maintaining such a sexual polymorphism and study some necessary conditions for the occurrence of a better performance of female and the variation of the magnitude of this advantage in Silene nutans. By population genomics approach, I compared the polymorphism of three genomes (nuclear, mitochondrial and chloroplast) of two species, gynodioïque, S. nutans and dioecious: Silene otites. I showed that gynodioecy is maintained in S. nutans through a frequency-dependent negative selection. A second part of my thesis concerns the occurrence and variation of the amplitude of the female advantage. With biology and genetic of population approach, I compared the reproductive success of females and hermaphrodites. I showed that the female advantage depends on the efficiency of pollination and selfing rates that vary according to the sex ratio in experimental conditions. Furthermore, I showed that natural population pollen flow were mainly restricted in space. I also showed that in the studied natural population the genetic determinism of gynodioecy is nuclear. Finally, I highlighted a greater contribution of nocturnal pollinators to reproductive success in S. nutans in relation to diurnal pollinators of this species
Audiffren, Julien. "Etude d'un système d'équations différentielles stochastiques : Le cliquet de Muller". Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10124.
Muller's Ratchet is a model from evolutionary theory describing the accumulation of deleterious mutations in asexually reproducing population. The lack of recombination implies that children have all the deleterious mutations of his parent. The minimal number of deleterious mutations carried in the population is an non-decreasing process, and if it increases we say that the Muller's ratchet clicks. The model studied in this thesis is an infinite system of stochastic differential equations. In the first chapter, we first prove that the ratchet clicks in finite time a.s., then that the clicking time has finite expectation. For this we use comparison arguments and time changes. In the second chapter, we prove that this model is equivalent to a modified look-down model with mutation and selection. In the third chapter we generalize the results of chapter 2 to a more general model
Egea, Emilie. "Histoire évolutive, structures génétique, morphologique et écologique comparées dans un complexe d'espèces jumelles : Echinocardium cordatum (Echinoidea, Irregularia)". Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22017.
Echinocardium cordatum (Pennant 1777) an abundant irregular sea urchin from the coastal temperate zones has long been considered as a cosmopolitan species which wide distribution area was the direct consequence of its planktotrophic larvae high dispersal abilities. A combined study of the genetic [mitochondrial and nuclear genomes (introns+microsatellites)], morphologic (based on 20 morphometric indices) and ecologic (geographic distribution at fine or large scale, and gonad maturation cycle) characteristics reveals that this taxon is a complex of cryptic species for which genetic differentiations concurred with morphological and ecological ones. The different species each occupy a limited geographic areas (clade A : Atlantic, clade SP : South Pacific, clade NP : North Pacific, clade B2 : Mediterranean sea, et clade B1 : Mediterranean sea and Atlantic coasts of Iberia). According to the complex species evolutionary history reconstruction, based on fossils and molecular data, the different species diverged between 3 (B1-B2) and 10 (A-rest) million years ago, driven by geologic and paleoclimatic perturbations (Tethys closure, messinian salinity crisis, Plio-Pleistocene glaciations). Molecular and morphologic polymorphisms appear reduced in B1, suggesting a reduced historical effective size. The contemporaneous genetic flux analysis reveals that clades A and B1 exchange genes whereas clades B1 and B2 developed an efficient reproductive isolation preventing hybridization. Though dispersal abilities of the complex species are high (more than 3000 km), they appear to be smaller than those of other species of the same genera, particularly E. mediterraneum which undergone the same geological perturbations without splitting into several species since its appearance some 28 million years ago. From an evolutionary point of view, taxa with high dispersal abilities should exhibit important population effective sizes, wide distribution areas and weak genetic differentiation between localities, properties that should slow species formation within these taxa. If this hypothesis seems verified in E. mediterraneum, it is not the case in E. cordatum for which the apparent high effective size and weak regional structure contrast with the fast speciation dynamics. It seems that other characteristics might be responsible for the speciation dynamic differences, and the comparison of the two taxa ecological requirements, as well as the isolation of the gene coding for the protein responsible of the sperm specific attachment, the bindin, should bring elements to answer these questions
Pujol, Benoît. "Dynamique évolutive de la diversité morphologique et génétique d'une plante domestiquée à "propagation végétative" : Le manioc (manihot esculenta crantz)". Montpellier 2, 2004. http://www.theses.fr/2004MON20125.
Reichert, Sophie. "Facteurs déterminant la longueur des télomères et implications dans les compromis évolutifs". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01023750.
Ismail, Mohannad. "Plasticité de la réponse à l'exposition au froid chez Aphidius ervi dans le cadre des processus de stockage utilisés en lutte biologique". Phd thesis, Université Rennes 1, 2011. http://tel.archives-ouvertes.fr/tel-00588289.
Lahiani, Emna. "Dynamique évolutive de la gynodioécie chez Silene nutans et conditions de son maintien en populations". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10045/document.
Gynodioecy - the coexistence of female and hermaphrodite individuals, is one of the most common systems after hermaphroditism in angiosperms. The maintenance and evolution of gynodioecy intrigued many evolutionary biologists. The aim of my thesis was to determine the evolutionary forces involved in maintaining such a sexual polymorphism and study some necessary conditions for the occurrence of a better performance of female and the variation of the magnitude of this advantage in Silene nutans. By population genomics approach, I compared the polymorphism of three genomes (nuclear, mitochondrial and chloroplast) of two species, gynodioïque, S. nutans and dioecious: Silene otites. I showed that gynodioecy is maintained in S. nutans through a frequency-dependent negative selection. A second part of my thesis concerns the occurrence and variation of the amplitude of the female advantage. With biology and genetic of population approach, I compared the reproductive success of females and hermaphrodites. I showed that the female advantage depends on the efficiency of pollination and selfing rates that vary according to the sex ratio in experimental conditions. Furthermore, I showed that natural population pollen flow were mainly restricted in space. I also showed that in the studied natural population the genetic determinism of gynodioecy is nuclear. Finally, I highlighted a greater contribution of nocturnal pollinators to reproductive success in S. nutans in relation to diurnal pollinators of this species
Lebreton, Sébastien. "Stratégies de ponte en situation de compétition chez une guêpe parasitoïde". Phd thesis, Université François Rabelais - Tours, 2009. http://tel.archives-ouvertes.fr/tel-00441637.
Mallet, Bertrand. "Rôle des facteurs écologiques dans le processus de spéciation en milieu insulaire. Effet de l'habitat et des pollinisateurs sur la diversification du faham (Jumellea spp., Orchidaceae) aux Mascareignes". Thesis, La Réunion, 2014. http://www.theses.fr/2014LARE0020/document.
Mechanisms responsible for the establishment of reproductive isolation are little studied in island adaptive radiations. According to the theory of ecological speciation, reproductive isolation results from the ecologically-based divergent selection. By their unique characteristics, oceanic islands are ideal systems to study the role of ecological factors in the diversification of endemic lineages. This study focuses on the role of habitat and pollinators in restricting inter and intraspecific gene flow between populations of faham (Jumellea spp.), an orchid endemic to Mascarene Islands. To do this, patterns of phenotypic differentiation (floral traits), environmental differentiation (habitat, altitude, climate) and genetic differentiation (nuclear microsatellites) were compared. At the intraspecific level, the results show that gene flow restriction is mainly due to the colonization of different habitat types with no obvious role of pollinators. At the interspecific level, in addition to the role of habitat, pollinator shift seems to explain effective complete reproductive isolation. By placing these results into the continuum of speciation, it appears that reproductive isolation evolve initially in response to adaptation to different habitats and, in a second phase, would be enhanced by pollinator-driven divergent selection. Operationally, this study reviews the taxonomy of faham and proposes to define management units and priorities in terms of conservation
Dahirel, Maxime. "Déterminants individuels et environnementaux de la dispersion chez une espèce hermaphrodite, l'escargot Cornu aspersum". Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S068/document.
Dispersal behaviours, i.e. movements leading to gene flow in space, play a key role in many ecological and evolutionary processes. Terrestrial gastropods are simultaneous hermaphrodites and have an extremely high cost of locomotion, a seldom studied combination of traits which makes them very valuable to investigate the links between dispersal and other life-History traits. During this project, we investigated (i) the complex relationships and trade-Offs between dispersal behaviour, growth, male and female reproduction in the anthropophilous brown garden snail Cornu aspersum, (ii) how its dispersal and exploration vary as a function of competition and environmental heterogeneity, (iii) how dispersal ability coevolved with other traits at the interspecific level. This snail presents a male-Biased subadult phase of varying duration before reaching adulthood and hermaphroditism. Dispersal behavior was mostly expressed during this subadult stage, and its decrease in adults was linked to investment in the female function. Brown garden snail dispersal is highly density-Dependant: snails leave crowded sites and settle readily in low-Density patches, a strategy that facilitates colonization and persistence in spatio-Temporally variable environments. Their movement propensity increases in urban, fragmented habitats, despite the higher costs of movement. At the interspecific level, dispersal and ecological generalism are linked in a dispersal syndrome, which makes specialist species doubly vulnerable, but increases success odds of generalists in heterogeneous landscapes . This combination of traits is likely to have played a major role in the successful worldwide colonization of many anthropogenic landscapes by this species
Stier, Antoine. "Implications du stress oxydant et du découplage mitochondrial dans les compromis entre traits d'histoire de vie". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01023812.
Daigle, Caroline. "Expansion d'une nouvelle famille de protéines kinases (MAPKKKs) impliquée dans le développement reproductif chez les Solanacées". Thèse, 2016. http://hdl.handle.net/1866/18509.
Mitogen-Activated Protein Kinases (MAPKs) signaling cascades are found in all Eucaryotes and allow signal transduction from the outside of the cell to the inside. In plants, they are particularly numerous and play roles in several signaling processes, including stress responses and response to developmental cues. Their system involves a phosphorelay: they interact with each other to transfer a phosphate group. It starts with an activated MAPKKK, which transfers the phosphate group to a MAPKK (MKK), then this MKK transfers the signal to a MAPK (MPK), which ends this relay by phosphorylating transcription factors or any other proteins that will, in a way or an other, change the cell response according to the signal. During the last few years, many MAPKs members have been studied for their role in plants sexual reproduction. Some mutants were characterized, but until now, our knowledge of complete signaling cascades is very limited. Previous studies in our lab have shown that two MAPKKKs from the MEKK subfamily, ScFRK1 and ScFRK2, are important for male and female gametophytes development in Solanum chacoense, a wild diploid potato species. Genes that are the most orthologous to ScFRK1 and ScFRK2 in Arabidopsis thaliana, AtMAPKKK19, 20 and 21, do not seem to play the same roles in reproduction, which led us to make the hypothesis that in solanaceous species, at least in S. chacoense, there is one MAPKKK family that is different and not present in A. thaliana. At first, we did analyze the genomes/transcriptomes/proteomes of 15 species from different clads of the plant kingdom to find all the members of the MEKK subfamily of MAPKKKs in order to study their phylogenetic relationship. We then observed that ScFRK1 and ScFRK2 are included in a large monophyletic group which was called the FRK class (Fertilization Related Kinase). Moreover, we also observed that this class has considerably expanded within the solanaceous species, compared to other species like A. thaliana, poplar, cotton or grape vine. The FRK class is totally absent in the monocot species studied (rice and maize) and only one member is found in the basal angiosperm Amborella trichopoda. This phylogenetic analysis led us to ask questions about the origins of the FRK class and its role inside the Solanaceae family. Secondly, we characterized ScFRK3, a third member of the FRK class in S. chacoense, which is also involved, as its two FRK sisters, in male and female gametophytes development. From its expression pattern to the establishment of a potential signaling cascade, analysis and phenotyping of ScFRK3 mutant lines, many experiments were realized in order to understand the role of ScFRK3 in S. chacoense sexual reproduction. Overall, the appearance of this new and expanded class of MEKKs questions its specific role in comparison to other species that have much lesser members, mainly when compared to the model plant A. thaliana, which harbor only a fifth of the FRKs found in solanaceous species.