Relevant bibliographies by topics / Asexual

Academic literature on the topic 'Asexual'

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Published: 4 June 2021
Last updated: 27 July 2024

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Journal articles on the topic "Asexual"

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Key, Adam. "The Silent A." Journal of Autoethnography 2, no. 4 (2021): 446–65. http://dx.doi.org/10.1525/joae.2021.2.4.446.

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This critical autoethnography explores experiences as an asexual cismale and the inherent tensions and struggles experienced in the dialectic between societal expectations of sexual desire as a man and the lack of sex drive characteristic of an asexual orientation. It explores the exclusion asexuals experience, as they occupy a third space between straightness and queerness, leaving them nowhere in either the gender or sexuality roles spectrums to truly call home. As asexuals exist in a space not often considered by heterosexual and queer individuals and asexual men exist between the tension of sexual expectation and orientation, music is utilized as a means of common language. This essay offers this connection through a series of autoethnographic glimpses, each set to a different song or lyric, as a soundtrack to give voice to the silenced experiences of asexuals.
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Auld, Stuart K. J. R., Shona K. Tinkler, and Matthew C. Tinsley. "Sex as a strategy against rapidly evolving parasites." Proceedings of the Royal Society B: Biological Sciences 283, no. 1845 (December 28, 2016): 20162226. http://dx.doi.org/10.1098/rspb.2016.2226.

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Why is sex ubiquitous when asexual reproduction is much less costly? Sex disrupts coadapted gene complexes; it also causes costs associated with mate finding and the production of males who do not themselves bear offspring. Theory predicts parasites select for host sex, because genetically variable offspring can escape infection from parasites adapted to infect the previous generations. We examine this using a facultative sexual crustacean, Daphnia magna, and its sterilizing bacterial parasite, Pasteuria ramosa . We obtained sexually and asexually produced offspring from wild-caught hosts and exposed them to contemporary parasites or parasites isolated from the same population one year later. We found rapid parasite adaptation to replicate within asexual but not sexual offspring. Moreover, sexually produced offspring were twice as resistant to infection as asexuals when exposed to parasites that had coevolved alongside their parents (i.e. the year two parasite). This fulfils the requirement that the benefits of sex must be both large and rapid for sex to be favoured by selection.
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Tobler, M., and I. Schlupp. "Expanding the horizon: the Red Queen and potential alternatives." Canadian Journal of Zoology 86, no. 8 (August 2008): 765–73. http://dx.doi.org/10.1139/z08-056.

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The Red Queen hypothesis (RQH) is one of the most widely accepted hypotheses explaining the persistence of sexual reproduction despite its costs. It posits that sexual species, compared with asexuals, are more adept at countering parasites, because their per-generation recombination rate is higher. Despite theoretical support, current empirical studies have failed to provide unanimous support. Here, we suggest that future tests of the RQH should more thoroughly elucidate its underlying assumptions and potential alternative hypotheses. While the RQH predicts that negative frequency-dependent selection shapes host–parasite interactions, differences between sexuals and asexuals are potentially important. Key assumptions about asexual species and their sexual close relatives include (i) ecological and behavioral traits are similar, (ii) among-individual genetic diversity is greater in sexuals than in asexuals, and (iii) within-individual genetic diversity is similar in asexuals and sexuals. We review current evidence for the RQH, highlight differences between asexual and sexual species and how those differences might translate into differential responses to parasite infections, and discuss how they can influence the results and interpretation of empirical studies. Considering differences between asexual and sexual species in future tests of the RQH will help to refine predictions and eliminate alternative hypotheses.
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Scheu, S., and B. Drossel. "Sexual reproduction prevails in a world of structured resources in short supply." Proceedings of the Royal Society B: Biological Sciences 274, no. 1614 (February 27, 2007): 1225–31. http://dx.doi.org/10.1098/rspb.2007.0040.

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We present a model for the maintenance of sexual reproduction based on the availability of resources, which is the strongest factor determining the growth of populations. The model compares completely asexual species to species that switch between asexual and sexual reproduction (sexual species). Key features of the model are that sexual reproduction sets in when resources become scarce, and that at a given place only a few genotypes can be present at the same time. We show that under a wide range of conditions the sexual species outcompete the asexual ones. The asexual species win only when survival conditions are harsh and death rates are high, or when resources are so little structured or consumer genotypes are so manifold that all resources are exploited to the same extent. These conditions, largely represent the conditions in which sexuals predominate over asexuals in the field.
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Larose, Chloé, Darren J. Parker, and Tanja Schwander. "Fundamental and realized feeding niche breadths of sexual and asexual stick insects." Proceedings of the Royal Society B: Biological Sciences 285, no. 1892 (November 28, 2018): 20181805. http://dx.doi.org/10.1098/rspb.2018.1805.

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The factors contributing to the maintenance of sex over asexuality in natural populations remain unclear. Ecological divergences between sexual and asexual lineages could help to maintain reproductive polymorphisms, at least transiently, but the consequences of asexuality for the evolution of ecological niches are unknown. Here, we investigated how niche breadths change in transitions from sexual reproduction to asexuality. We used host plant ranges as a proxy to compare the realized feeding niche breadths of five independently derived asexual Timema stick insect species and their sexual relatives at both the species and population levels. Asexual species had systematically narrower realized niches than sexual species, though this pattern was not apparent at the population level. To investigate how the narrower realized niches of asexual species arise, we performed feeding experiments to estimate fundamental niche breadths but found no systematic differences between reproductive modes. The narrow realized niches found in asexual species are therefore probably a consequence of biotic interactions such as predation or competition, that constrain realized niche size in asexuals more strongly than in sexuals.
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Thomsen, Erik, and Eckart Håkansson. "Sexual versus asexual dispersal in clonal animals: examples from cheilostome bryozoans." Paleobiology 21, no. 4 (1995): 496–508. http://dx.doi.org/10.1017/s0094837300013506.

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The relative numbers of sexually and asexually recruited colonies and the proportion of brooding zooids were determined in 26 species of cheilostome bryozoans of Late Cretaceous and Early Tertiary ages. Asexual reproduction seems to be much more widespread than previously realized, although its relative importance is related to growth habit. Arborescent species of these fossil assemblages reproduce mainly asexually via fragmentation; encrusting species reproduce sexually via motile larvae. Free-living species use both methods; some reproduce sexually, whereas other species have enhanced the ability to break and reproduce predominantly asexually. Mode of reproduction was stable over a period of 3 m.y. in all species except the vinelike Columnotheca cribrosa. In this species both the proportion of asexual recruits and brooding zooids varied in accord with environmental parameters. In all cases populations dominated by asexual propagation had a significantly lower proportion of brooding zooids than populations dominated by sexual propagation.
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Amat, Isabelle, Jacques J. M. van Alphen, Alex Kacelnik, Emmanuel Desouhant, and Carlos Bernstein. "Adaptations to different habitats in sexual and asexual populations of parasitoid wasps: a meta-analysis." PeerJ 5 (September 12, 2017): e3699. http://dx.doi.org/10.7717/peerj.3699.

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BackgroundCoexistence of sexual and asexual populations remains a key question in evolutionary ecology. We address the question how an asexual and a sexual form of the parasitoidVenturia canescenscan coexist in southern Europe. We test the hypothesis that both forms are adapted to different habitats within their area of distribution. Sexuals inhabit natural environments that are highly unpredictable, and where density of wasps and their hosts is low and patchily distributed. Asexuals instead are common in anthropic environments (e.g., grain stores) where host outbreaks offer periods when egg-load is the main constraint on reproductive output.MethodsWe present a meta-analysis of known adaptations to these habitats. Differences in behavior, physiology and life-history traits between sexual and asexual wasps were standardized in term of effect size (Cohen’sdvalue; Cohen, 1988).ResultsSeeking consilience from the differences between multiple traits, we found that sexuals invest more in longevity at the expense of egg-load, are more mobile, and display higher plasticity in response to thermal variability than asexual counterparts.DiscussionThus, each form has consistent multiple adaptations to the ecological circumstances in the contrasting environments.
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Mee, J. A., and L. Rowe. "A comparison of parasite loads on asexual and sexual Phoxinus (Pisces: Cyprinidae)." Canadian Journal of Zoology 84, no. 6 (June 2006): 808–16. http://dx.doi.org/10.1139/z06-064.

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In light of the inherent disadvantages of sexual reproduction, the existence of sex is often seen as a paradox. There are a variety of hypothetical benefits of sexual reproduction that may balance its disadvantages. The Red Queen hypothesis proposes that sexually reproducing species are better able to evolve resistance to parasites than asexually reproducing species. A prediction of the Red Queen hypothesis is that a parasite should evolve to preferentially exploit an asexual species over a sexual species. To test this central prediction of the Red Queen hypothesis, intensity of infection by the parasite Gyrodactylus eos Mayes, 1977 (Monogenea) was compared between sympatric asexual and sexual fish species in the genus Phoxinus Rafinesque, 1820. In each lake where these species coexist, the asexual fish should suffer higher intensities of infection than the sexual fish. In the majority of lakes sampled, there were more parasites on asexual than sexual fish.
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Boyer, Loreleï, Roula Jabbour-Zahab, Pauline Joncour, Sylvain Glémin, Christoph R. Haag, and Thomas Lenormand. "Asexual male production by ZW recombination in Artemia parthenogenetica." Evolution 77, no. 1 (December 8, 2022): 1–12. http://dx.doi.org/10.1093/evolut/qpac008.

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Abstract In some asexual species, parthenogenetic females occasionally produce males, which may strongly affect the evolution and maintenance of asexuality if they cross with related sexuals and transmit genes causing asexuality to their offspring (“contagious parthenogenesis”). How these males arise in the first place has remained enigmatic, especially in species with sex chromosomes. Here, we test the hypothesis that rare, asexually produced males of the crustacean Artemia parthenogenetica are produced by recombination between the Z and W sex chromosomes during non-clonal parthenogenesis, resulting in ZZ males through loss of heterozygosity at the sex determination locus. We used RAD-sequencing to compare asexual mothers with their male and female offspring. Markers on several sex-chromosome scaffolds indeed lost heterozygosity in all male but no female offspring, suggesting that they correspond to the sex-determining region. Other sex-chromosome scaffolds lost heterozygosity in only a part of the male offspring, consistent with recombination occurring at a variable location. Alternative hypotheses for the production of these males (such as partial or total hemizygosity of the Z) could be excluded. Rare males are thus produced because recombination is not entirely suppressed during parthenogenesis in A. parthenogenetica. This finding may contribute to explaining the maintenance of recombination in these asexuals.
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Przybylo, E., and D. Cooper. "Asexual Resonances: Tracing a Queerly Asexual Archive." GLQ: A Journal of Lesbian and Gay Studies 20, no. 3 (January 1, 2014): 297–318. http://dx.doi.org/10.1215/10642684-2422683.

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Dissertations / Theses on the topic "Asexual"

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Cortes, Blanca R. "Horizontal genetic transfer in asexual fungi." FIU Digital Commons, 2000. http://digitalcommons.fiu.edu/etd/2644.

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Four aspects of horizontal genetic transfer during heterokaryon formation were examined in the asexual pathogen Fusarium oxysporum f.sp. cubense (Foe): 1) variability based on method of heterokaryon formation 2) differences in nuclear and mitochondrial inheritance 3) the occurrence of recombination without nuclear fusion 4) the occurrence of horizontal genetic transfer between distantly related isolates. The use of non- pathogenic strains of Fusarium oxysporum as biocontrol agents warrants a closer examination at the reproductive life cycle of this fungus, particularly if drag resistance or pathogenicity genes can be transmitted horizontally. Experiments were divided into three phases. Phase I looked at heterokaryon formation by hyphal anastomosis and protoplast fusion. Phase II was a time course of heterokaryon formation to look at patterns of nuclear and mitochondrial inheritance. Phase III examined the genetic relatedness of the different vegetative compatibility groups using a multilocus analysis approach. Heterokaryon formation was evident within and between vegetative compatibility groups. Observation of non-parental genotypes after heterokaryon formation confirmed that, although a rare event, horizontal genetic transfer occurred during heterokaryon formation. Uniparental mitochondria inheritance was observed in heterokaryons formed either by hyphal anastomosis or protoplast fusion. Drag resistance was expressed during heterokaryon formation, even across greater genetic distances than those distances imposed by vegetative compatibility. Phytogenies inferred from different molecular markers were incongruent at a significant level, challenging the clonal origins of Foe. Mating type genes were identified in this asexual pathogen Polymorphisms were detected within a Vegetative Compatibility Group (VCG) suggesting non-clonal inheritance and/or sexual recombination in Foe. This research was funded in part by a NIH-NIGMS (National Institutes of Health-National Institute of General Medical Sciences) Grant through the MBRS (Minority Biomedical Research Support), the Department of Biological Sciences and the Tropical Biology Program at FIU.
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Laaka-Lindberg, Sanna. "Ecology of asexual reproduction in hepatics /." Helsinki : Yliopistopaino, 2000. http://ethesis.helsinki.fi/julkaisut/mat/ekolo/vk/laaka-lindberg.

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Polak, Eline. "Asexual sporulation in the basidiomycete Coprinus cinereus /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13125.

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Gingas, Vicki Marie. "Asexual embryogenesis and plant regeneration in Quercus /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487588939088322.

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Jenkins, Christina. "Resource limitation in sexual vs. asexual Potamopyrgus antipodarum." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/521.

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The question of why sexual reproduction is so prevalent in natural populations has been called the "queen of questions" in evolutionary biology (Bell, 1982). One potential answer to this question may come from studying whether sexuals and asexuals respond differently to a resource-limited environment. If asexuals require more resources to grow and reproduce at the same rate as sexuals, it could negate the two-fold cost of sexual reproduction. Here, I use Potamopyrgus antipodarum, to empirically address this possibility. First, I consider whether differences in genetic diversity between sexual and asexual components of a population could help to maintain sex in a resource-limited environment. This possible advantage associated with asexuality requires that genetically identical individuals compete more for the same resources than genetically diverse individuals. I evaluated this possibility by comparing fitness-related traits in genetically homogeneous vs. heterogeneous populations of asexual female P. antipodarum, and found that adult size was a more important determinant of individual growth and reproduction than population genetic diversity per se. Next, I used manipulations of density of experimental populations of P. antipodarum to assess whether asexual females experienced a sharper decline in fitness-related traits under high-density conditions, as expected if high sensitivity of asexual individuals to food limitation might contribute to the maintenance of sex. Counter to these predictions, I found that sexual females in fact suffered even more in high-density predictions. Finally, I considered that asexuals may respond differently to food quality, instead of quantity. Ecological stoicheometry postulates that individual growth and reproduction is associated with their bodily phosphorous (P) and the available P in food found in their environment. Because asexuals have more bodily P they may require more P rich food than sexuals to grow and reproduce at the same rate. Although asexuals reproduced less than sexuals, it was not a significant difference.
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Söderberg, Jonas. "Surviving the ratchet : Modelling deleterious mutations in asexual populations." Doctoral thesis, Uppsala universitet, Molekylär evolution, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-157897.

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One of the most unforgiving processes in nature is that of Muller's ratchet, a seemingly irreversible accumulation of deleterious mutations that all organisms have to deal with or face extinction. The most obvious way to avoid fitness collapse is recombination, though asexual populations usually do not have the luxury of recombining freely.  With the aid of computational and mathematical models, we have studied other situations where this threat is averted and the organism can survive the ratchet. The results show that a ratchet where all mutations have the same deleterious fitness effect is very effectively stalled for large effects. However, if mutations are allowed to have a broad range of effects, the fitness-loss rate can be substantial even with the same mean effect as the one-type ratchet, but we have  identified parameter regions where even the broad-range effects are effectively stopped. The fitness-loss from a ratchet is very sensitive to the mutation rate and a mutation that increases the mutation rate (mutator) can easily start an otherwise stalled ratchet. Large effect mutators are heavily counter-selected, but smaller mutators can spread in the population. They can be stopped by reversals (antimutators), but even if the mutation rate is equilibrated in this way, there will be large fluctuations in mutation rate and even larger in the fitness-loss rate due to the feedback amplification in their coupling.    Another way of preventing the ratchet is by reversal of the deleterious mutations themselves through back-mutations or compensatory mutations. The rate required to stop the ratchet using only back-mutations before the fitness collapses is very large. A detailed comparison between the deleterious mutations in the ratchet and in a sexual population was made and the difference was found to be greatest for large populations with large genomes. There are obviously many ways to survive the ratchet, but even more ways to drive a species to extinction by enhancing and speeding up the ratchet. By modelling and testing the ratchet for numerous different situations, we show the effects of some of these threats and benefits.
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Ricci, Lorenzo. "A new model to study alternative developments : asexual propagation and regeneration in the basal chordate Botryllus schlosseri." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066683.

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Chez l’ascidie coloniale Botryllus schlosseri, en plus de l’embryogénèse existent deux voies de développement aboutissant à la production de la même structure : l’organisme adulte ou zooide. Ces développements alternatifs ont lieu lors de processus biologiques distincts : le bourgeonnement palléal (BP) et le bourgeonnement vasculaire (BV). Le BP est un processus de multiplication asexuée présentant une ontogénèse stéréotypée. En revanche, le BV est un phénomène régénératif, induit dans les vaisseaux sanguins de la colonie par l’ablation de tous les zooides et bourgeons palléaux. Mes travaux de recherche ont eu pour objectif de caractériser les bases moléculaires et cellulaires régissant le BP et le BV chez B. schlosseri. L’étude de gènes marqueurs des lignées méso-, endo- et ectodermiques a révélé l’existence de territoires présomptifs pour chacune de ces lignées, dès les premiers stades du BV et du BP, et suggéré l’existence d’un programme unique aux deux processus. Les lignées neurales et musculaires ont été étudiées plus en détail lors du BP, indiquant un double rôle potentiel, neuro- et myo-génétique, au tube dorsal, une structure jusqu’à présent uniquement associée au système nerveux. Une caractérisation morphologique poussée a mené à l’identification de stades précoces stéréotypés du BV lors de la régénération. Enfin, l’analyse de transcriptomes de différents stades du BP et de la régénération ont initié l’étude non biaisée des bases moléculaires du bourgeonnement chez Botryllus. L’objectif à long terme de ces travaux est de décrypter les bases moléculaires et génétiques facilitant, chez les métazoaires, l’évolution de voies de développement alternatives
In addition to embryogenesis, the colonial ascidians Botryllus schlosseri evolved two alternative developmental pathways leading to the same final structure: the adult body, or zooid. These non-embryonic ontogenesis occur during distinct biological processes: palleal budding (PB) and vascular budding (VB). PB is a process of asexual propagation, with a very stereotyped morphogenesis. Conversely, VB is a purely regenerative phenomenon, induced in the vascular system of the colony by the ablation of all zooids and palleal buds. My research work followed the objective to characterize the molecular and cellular basis of both PB and VB in B. schlosseri. The study of meso-, endo- and ectodermal lineage marker genes revealed the existence of presumptive territories of these lineages in the early palleal and vascular buds and that a single developmental program was launched in both VB and PB. Neural and muscle fates were studied in more detail for PB, indicating a potential double function, both neuro- and myo-genic for the dorsal tube, a structure so far associated with the nervous system only. A detailed morphological description of VB allowed to identify stereotyped stages during early regeneration. Eventually, a transcriptomic characterization of early VB and PB processes initiated an unbiased study of the molecular basis underlying the budding phenomenon in Botryllus. The overall goal of these research works is to unravel the molecular and genetic basis that facilitated, in Botryllus and globally in metazoan, the evolution of alternative developmental pathways
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Docking, T. Roderick. "The evolution of retrotransposon sequences in four asexual plant species /." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81327.

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Since their discovery, transposable elements (TEs) have been regarded either as useful building blocks of genomes, or as "selfish DNA": genetic parasites that exploit the sexual cycle to spread in copy number within populations to the detriment of their hosts. If the "selfish DNA" hypothesis is correct, TEs are expected to deteriorate and be lost from asexual populations. This thesis tests the predictions of the "selfish DNA" hypothesis in four asexual plant species, focusing on patterns of nucleotide diversity and nucleotide substitution. Sequences bearing strong resemblance to known TE families including Ty1/copia, Ty3/gypsy, and LINE-like elements were successfully isolated from all four plant species, and showed patterns of nucleotide substitution consistent with a long history of purifying selection. Stochastic simulations were also conducted, and suggested that this result is expected if the host species has been asexual for less than tens of thousands of generations.
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Luk, Ka Wing. "An exploratory study of asexual marriage on a Chinese website." HKBU Institutional Repository, 2013. https://repository.hkbu.edu.hk/etd_oa/30.

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The process of individualization is increasingly permeating all levels of Chinese society. This research attempts to highlight some aspects on how Chinese individualization is emerging in marriage and the family through the prism of China’s emerging “asexual marriage” – a consensual partnership that has no sex or a limited amount of sex. Collecting qualitative data in different ways, this study first examines the less obvious and less studied effects of China’s sexual revolution as part of the individualization process brought to the asexual individuals on a specific matchmaking website WX920. One can see that these individuals undergo great suffering and are under pressure to find a partner in light of the sexual imperative in the couple relationship. My study also focuses on the idealized view of asexual marriage currently promoted by the rhetoric of affection. What is particularly striking is that the same ideal is perceived as equally worthy of a relationship in a proforma marriage with a homosexually inclined person, when one cannot meet an asexual partner. In addition, this study suggests the reintegration of individuals into a new type of collectivity – the family, which is primarily structured as a unit of emotional importance to the individual’s marital decision. Nevertheless, the other side of family connection constitutes a crucial dilemma for some non-conformist individuals, who are confronted with a dual demand for satisfying personal aspirations and family expectations. Drawing on the concept of “negotiated familism”, this study reveals how these individuals are by no means passive recipients and they actively engage in negotiation about their ideal of personal life through a marriage in form only. Finally, I will engage a discussion on individualizing trends by exploring asexual people’s reorganization of conventional norms of marriage and other expectations such as reproduction is given.
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Dench, Jonathan. "New Computational Approaches to Study the Evolution of Asexual Haploids." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40415.

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Numerous factors can influence the evolutionary fate of mutations. Despite this, we tend to study strong evolutionary drivers, or evolution under simple contexts, in part because they are the conditions we have a means to study. My thesis evaluates novel computational approaches to advance detection, and study, of factors that influence a mutation’s evolutionary outcome. First, I present the novel computational tool AEGIS that I use to detect phylogenetic signals of correlated evolution followed by an experimental approach to evaluate the role of epistasis as a potential cause of correlated evolution among sites associated with antibiotic resistance in Pseudomonas aeruginosa. Second, I developed rSHAPE, a novel in silico approach for experimental evolution with asexual haploids, to complement empirical work by providing a common framework in which to test various evolutionary scenarios. After demonstrating that rSHAPE replicates the expected evolutionary dynamics of de novo mutations, I provide evidence that the common laboratory practice of serial passaging may increase stochasticity of evolutionary outcome. Through my work, I have demonstrated that a marriage of computational and experimental approaches will offer new opportunities to understand how the interaction of evolutionary factors influence the fate of mutations.
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Books on the topic "Asexual"

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Rothblum, Esther D. Boston marriages: Romantic but asexual relationships among contemporary lesbians. Amherst: University of Massachusetts Press, 1993.

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Rubt͡sova, Z. M. Ėvoli͡ut͡sionnoe znachenie apomiksisa: Istoriko-kriticheskoe issledovanie. Leningrad: "Nauka," Leningradskoe otd-nie, 1989.

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Foster, Aasha. Measuring social invisibility and erasure: Development of the Asexual Microaggressions Scale. [New York, N.Y.?]: [publisher not identified], 2017.

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Phillips, Sarah Wynne. Asexual overwintering and morph determination in the lettuce root aphid Pemphigus bursarius (L.). Birmingham: University of Birmingham, 1999.

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Togashi, Tatsuya. The evolution of anisogamy: A fundamental phenomenon underlying sexual selection. New York: Cambridge University Press, 2011.

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Enderlein, Gunther. Bacteria cyclogeny: Prolegomena to a study of the structure, sexual and asexual reproduction and development of bacteria. Prescott, Ariz: Enderlein Enterprises Inc., 1998.

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Enderlein, Günther. Bacteria cyclogeny: Prolegomena to a study of the structure, sexual and asexual reproduction and development of bacteria. Prescott, Ariz: Enderlein Enterprises, 1999.

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1940-, Bogart James P., Dawley Robert Martin, New York State Museum, and University of the State of New York. State Education Dept., eds. Evolution and ecology of unisexual vertebrates. Albany, N.Y: University of the State of New York, State Education Dept., 1989.

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Gillis, Janice Maureen. Light and electron microscopic observations of in vitro excystation and asexual development of two bovine sarcocystis species (apicomplexa, sarcocystidae). Charlottetown: University of Prince Edward Island, 1993.

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Quist, Jeremy. Asexual. Mason Crest, 2022.

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Book chapters on the topic "Asexual"

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Hangay, George, Severiano F. Gayubo, Marjorie A. Hoy, Marta Goula, Allen Sanborn, Wendell L. Morrill, Gerd GÄde, et al. "Asexual." In Encyclopedia of Entomology, 305. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6359-6_10357.

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William Birky, C., and Timothy G. Barraclough. "Asexual Speciation." In Lost Sex, 201–16. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2770-2_10.

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Mehlhorn, Heinz. "Asexual Reproduction." In Encyclopedia of Parasitology, 234. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-43978-4_3655.

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Mehlhorn, Heinz. "Asexual Reproduction." In Encyclopedia of Parasitology, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-27769-6_3655-1.

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Pandian, T. J. "Asexual Reproduction." In Reproduction and Development in Echinodermata and Prochordata, 94–135. Boca Raton, FL : CRC Press, Taylor & Francis Group, [2018] | Series: Reproduction and development in aquatic invertebrates ; volume 3 | “A science publishers book.”: CRC Press, 2018. http://dx.doi.org/10.1201/9780815364733-4.

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Edge, Jared. "Asexual Reproduction." In Encyclopedia of Animal Cognition and Behavior, 1–6. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-47829-6_325-1.

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Edge, Jared. "Asexual Reproduction." In Encyclopedia of Animal Cognition and Behavior, 481–86. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-319-55065-7_325.

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Simon, Kay A., Alyssa N. Clark, and Ryan J. Watson. "Asexual Youth." In Encyclopedia of Adolescence, 1–6. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-319-32132-5_824-1.

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Kim, Eunjung. "Asexual Kinship." In Asexualities, 305–21. London: Routledge, 2024. http://dx.doi.org/10.4324/9781003178798-25.

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Jacobs, Joela, and Nicole Seymour. "Asexual Ecologies." In Asexualities, 23–36. London: Routledge, 2024. http://dx.doi.org/10.4324/9781003178798-4.

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Conference papers on the topic "Asexual"

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Ahmadian, Sajad, and Ali Reza Khanteymoori. "Training back propagation neural networks using asexual reproduction optimization." In 2015 7th Conference on Information and Knowledge Technology (IKT). IEEE, 2015. http://dx.doi.org/10.1109/ikt.2015.7288738.

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Noei, Mohammadreza, and Mohammad Saniee Abadeh. "A Genetic Asexual Reproduction Optimization Algorithm for Imputing Missing Values." In 2019 9th International Conference on Computer and Knowledge Engineering (ICCKE). IEEE, 2019. http://dx.doi.org/10.1109/iccke48569.2019.8964808.

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"An asexual genetic algorithm for the smallholders’ demand selection problem." In The 9th International Food Operations and Processing Simulation Workshop. CAL-TEK srl, 2023. http://dx.doi.org/10.46354/i3m.2023.foodops.008.

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Jiao, Shuyun, Yanbo Wang, and Ping Ao. "Dynamics of coexistence of asexual and sexual reproduction in adaptive landscape." In 2012 IEEE 6th International Conference on Systems Biology (ISB). IEEE, 2012. http://dx.doi.org/10.1109/isb.2012.6314135.

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Mahmoudi, Sina, Ebrahim Jelvehfard, and Mohammad-Shahram Moin. "Evolutionary fractal image compression using asexual reproduction optimization with guided mutation." In 2013 8th Iranian Conference on Machine Vision and Image Processing (MVIP). IEEE, 2013. http://dx.doi.org/10.1109/iranianmvip.2013.6780022.

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Ross, R., and R. Hall. "A FPGA Simulation Using Asexual Genetic Algorithms for Integrated Self-Repair." In First NASA/ESA Conference on Adaptive Hardware and Systems (AHS'06). IEEE, 2006. http://dx.doi.org/10.1109/ahs.2006.3.

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Hashemi, Seyyed Mohammad R., Ehsan Kozegar, Mohammad Mahdi Deramgozin, and Behrouz Minaei-Bidgoli. "Training Feed-forward Neural Networks using Asexual Reproduction Optimization (ARO) Algorithm." In 2019 5th Conference on Knowledge Based Engineering and Innovation (KBEI). IEEE, 2019. http://dx.doi.org/10.1109/kbei.2019.8735035.

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Yalong, Zhang, Hao Yongjun, Li Hongye, Chen Peng, Lian Chengbin, and Bao Xuan. "Global Path Planning of Unmanned Underwater Vehicle with Asexual Reproduction Optimization." In 2023 IEEE 11th International Conference on Computer Science and Network Technology (ICCSNT). IEEE, 2023. http://dx.doi.org/10.1109/iccsnt58790.2023.10334570.

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Tongnunui, Prasert, Prasert Tongnunui, Woraporn Tarangkoon, Woraporn Tarangkoon, Parichat Hukiew, Parichat Hukiew, Patcharee Kaeoprakan, et al. "SEAGRASS RESTORATION: AN UPDATE FROM TRANG PROVINCE, SOUTHWESTERN THAILAND." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b9447ad58f1.23030316.

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Natural disasters may adversely affect coastal resources potentially leading to coastal habitat restorations that incorporate stakeholders and the general public. Appropriate methodologies for habitat restoration are developed to ensure the outcomes of this project. Currently, seagrass bed restoration by means of asexual and sexual propagation techniques have been used worldwide. However, the experience of seagrass (Enhalus acoroides) habitat restoration in Trang Province noted that to accomplish this project’s strategies involved the application of restoration techniques along with public and stakeholder participation. The application of asexual propagation, specifically the collection of single shoots from donor seagrasses and subsequent transplantation, is a convenient tool. However, from this project results, this process still has conceptual problems as from the large numbers of single shoots collected from donor seagrasses, the survival rate was relatively low. Furthermore, this process was complicated by conflicting interests between local communities near to the donor site and the project’s organizers. In order to reduce said conflicts, other techniques to balance stakeholder interests were instigated by this project, namely the development of both asexual and sexual propagation techniques. This project initiated a sexual propagation technique by the collection of wild seeds of Enhalus acoroides that were subsequently grown in the laboratory before natural habitat transplantation. This project results showed that seeds can be grown rapidly and can be cultured in large numbers. However, this development technique has a limit on rearing time because seedlings were found to be in decline after the third month of the experiment. These problems were compounded by a limiting factor that pushed the project’s organizers to decide to transplant seagrasses from the laboratory to the wild whether a time was seasonally suitable or unsuitable, the planting activity still done forward. This matter may have enhanced the low survival rate situation after seagrass transplantation to the wild. If there is a need to recover a seagrass bed, the above culture and transplantation methodologies should be used in conjunction with repeated periodic plantings until natural ecological function has been restored. In conclusion, further research should be instigated to improve the cultivation method for producing ready to plant seedlings and to improve methods of project operation.
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Tongnunui, Prasert, Prasert Tongnunui, Woraporn Tarangkoon, Woraporn Tarangkoon, Parichat Hukiew, Parichat Hukiew, Patcharee Kaeoprakan, et al. "SEAGRASS RESTORATION: AN UPDATE FROM TRANG PROVINCE, SOUTHWESTERN THAILAND." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431687e149.

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Natural disasters may adversely affect coastal resources potentially leading to coastal habitat restorations that incorporate stakeholders and the general public. Appropriate methodologies for habitat restoration are developed to ensure the outcomes of this project. Currently, seagrass bed restoration by means of asexual and sexual propagation techniques have been used worldwide. However, the experience of seagrass (Enhalus acoroides) habitat restoration in Trang Province noted that to accomplish this project’s strategies involved the application of restoration techniques along with public and stakeholder participation. The application of asexual propagation, specifically the collection of single shoots from donor seagrasses and subsequent transplantation, is a convenient tool. However, from this project results, this process still has conceptual problems as from the large numbers of single shoots collected from donor seagrasses, the survival rate was relatively low. Furthermore, this process was complicated by conflicting interests between local communities near to the donor site and the project’s organizers. In order to reduce said conflicts, other techniques to balance stakeholder interests were instigated by this project, namely the development of both asexual and sexual propagation techniques. This project initiated a sexual propagation technique by the collection of wild seeds of Enhalus acoroides that were subsequently grown in the laboratory before natural habitat transplantation. This project results showed that seeds can be grown rapidly and can be cultured in large numbers. However, this development technique has a limit on rearing time because seedlings were found to be in decline after the third month of the experiment. These problems were compounded by a limiting factor that pushed the project’s organizers to decide to transplant seagrasses from the laboratory to the wild whether a time was seasonally suitable or unsuitable, the planting activity still done forward. This matter may have enhanced the low survival rate situation after seagrass transplantation to the wild. If there is a need to recover a seagrass bed, the above culture and transplantation methodologies should be used in conjunction with repeated periodic plantings until natural ecological function has been restored. In conclusion, further research should be instigated to improve the cultivation method for producing ready to plant seedlings and to improve methods of project operation.
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Reports on the topic "Asexual"

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Gazit, Shmuel, and Robert Knight, Jr. Asexual Embryogenesis in the Mango (Mangifera indica L). United States Department of Agriculture, February 1989. http://dx.doi.org/10.32747/1989.7593408.bard.

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Rochel Ortega, Elizabeth, Jefersson Andrés Rodríguez Blandón, Pedro David Suárez Villota, and Jorge Andrés Castillo. Taxonomía y material genético: propagación de material vegetal. Corporación colombiana de investigación agropecuaria - AGROSAVIA, 2021. http://dx.doi.org/10.21930/agrosavia.infografia.2021.26.

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Bell, Alexa. Romantic Identity and LGBTQ Identification: Variations of Experience in the Asexual Community. Portland State University Library, January 2015. http://dx.doi.org/10.15760/honors.159.

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Tippery, Nicholas, Nathan Harms, Matthew Purcell, Sun Lee Hong, Patrick Häfliger, Katelin Killoy, Ashley Wolfe, and Ryan Thum. Assessing the genetic diversity of Nymphoides peltata in the native and adventive range using microsatellite markers. Engineer Research and Development Center (U.S.), February 2024. http://dx.doi.org/10.21079/11681/48222.

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Nymphoides peltata (yellow floatingheart), native to Eurasia, is an invasive plant in the USA, where it grows in relatively isolated but widespread populations. The species is capable of sexual reproduction by seed and asexual reproduction through fragmentation. Although N. peltata is recognized as a noxious weed, little is known about its geographic region of origin or its dispersal mechanisms and relative amount of genetic variation in its adventive range. We conducted a genetic analysis of N. peltata by studying 68 localities across the native range and 47 localities in the adventive range, using microsatellite markers to determine genetic variability within and among populations, and to infer regions in the native range from which invasive plants originated. A large number of sites in the USA were genetically identical to one another, and there were two predominant multilocus allele phenotypes that were distributed in the northern and southern latitudes, respectively. Additional USA sites were similar to one of the predominant genetic profiles, with greater genetic diversity in southern populations. The genetically identical sites are consistent with asexual spread, potentially via anthropogenic mechanisms. Plants across the USA range were observed to produce viable seeds, and some genetic variation could be explained by sexual reproduction. All USA plants were more similar to plants in Europe than they were to plants in Asia, indicating that the plants likely were introduced originally from Europe. The existence of two genetic clusters and their similarity to plants in different parts of Europe constitute evidence for at least two N. peltata introductions into the USA.
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Cothron, Annaliese, Don Clermont, Amber Shaver, Elizabeth Alpert, and Chukwuebuka Ogwo. Improving Knowledge, Comfort, and Attitudes for LGBTQIA+ Clinical Care and Dental Education. American Institute of Dental Public Health, 2023. http://dx.doi.org/10.58677/tvin3595.

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Oral health does not exist in a silo. The mouth-body connection is a biological aspect of physical wellbeing that exists alongside the social and political drivers of whole-person health. Lesbian, gay, bisexual, transgender, queer, intersex, and agender/ asexual people, and people of other marginalized gender or sexual identities (LGBTQIA+), have experienced historical exclusion from healthcare systems perpetuated by chronic stigma. Ongoing discrimination, cultural insensitivity, and blatant homophobia/transphobia among healthcare staff results in poor health outcomes, including oral health. These exchanges either facilitate or inhibit respectful, high-quality, patient-centered care cognizant of intersectionality. In 2022, the American Institute of Dental Public Health (AIDPH) disseminated a mixed-methods survey to just over 200 oral health professionals to assess knowledge, attitudes, and practices regarding LGBTQIA+ oral health.
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Ohad, Nir, and Robert Fischer. Control of Fertilization-Independent Development by the FIE1 Gene. United States Department of Agriculture, August 2000. http://dx.doi.org/10.32747/2000.7575290.bard.

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A fundamental problem in biology is to understand how fertilization initiates reproductive development. During plant reproduction, one sperm cell fuses with the egg to form an embryo, whereas a second sperm cell fuses with the adjacent central cell nucleus to form the endosperm tissue that supports embryo and/or seedling development. To understand the mechanisms that initiate reproduction, we have isolated mutants of Arabidopsis that allow for replication of the central cell and subsequent endosperm development without fertilization. In this project we have cloned the MEA gene and showed that it encode a SET- domain polycomb protein. Such proteins are known to form chromatin-protein complexes that repress homeotic gene transcription and influence cell proliferation from Drosophylla to mammals. We propose a model whereby MEA and an additional polycomb protein we have cloned, FIE , function to suppress a critical aspect of early plant reproduction and endosperm development, until fertilization occurs. Using a molecular approach we were able to determine that FIE and MEA interact physically, suggesting that these proteins have been conserved also during the evolution of flowering plants. The analysis of MEA expression pattern revealed that it is an imprinted gene that displays parent-of- origin-dependent monoallelic expression specifically in the endosperm tissue. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds support the parental conflict theory for the evolution of imprinting in plants and mammals. These results contribute new information on the initiation of endosperm development and provide a unique entry point to study asexual reproduction and apomixis which is expected to improve crop production.
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Sherman, A., D. N. Kuhn, Y. Cohen, R. Ophir, and R. Goenaga. Exploring the polyembryonic seed trait in mango as a basis for a biotechnology platform for fruit tree crops. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2021. http://dx.doi.org/10.32747/2021.8134176.bard.

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Mango is one of the most important fruit crops. However, the biology of this fruit tree is under studied. The lack of genetic and genomic resources has limited progress in mango research and breeding. Several research groups have recently started developing genomic tools for mango by creating transcriptome and genomic data. Sexual reproduction in plants is the main pathway for the creation of new genetic combinations. In modern agriculture, breeders exploit the genetic diversity generated through sexual reproduction to develop elite cultivars; however, these cultivars require genetic stabilization before they are suitable for mass propagation for uniform crop production. In heterozygous plants such as fruit trees, vegetative propagation (cloning) is the primary path for the propagation of genetically uniform plants. Another natural plant mechanism that can create genetically uniform plants (clones) is apomixes. Apomixis is defined as asexual reproduction through seeds that lead to the production of clonal progeny whose genotype is identical to that of the mother plant. In fruit crops like citrus and mango, sporophytic apomixes result in polyembryony, where seeds contain multiple embryos, one of which is sexually originated, and the others are clones of the mother tree. As part of this research, the reference genome of mango was established as a basic platform for mango breeding and research. It was used to map two important mango traits fruit size and polyembryony. The draft genome 'Tommy Atkins' sequence was generated using NRGene de-novo Magic on high molecular weight DNA of 'Tommy Atkins,' supplemented by 10X Genomics long read sequencing to improve the initial assembly. The final 'Tommy Atkins' genome assembly was a consensus sequence that included 20 pseudomolecules representing the 20 chromosomes of mango. The availability of a genome enables the genetic dissection of important traits. We demonstrated the utility of the genome assembly and the 'Tommy Atkins' x 'Kensington Pride' map by analyzing fruit weight phenotypic data and identifying two QTLs for this trait.
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Israel, Alvaro, and John Merrill. Production of Seed Stocks for Sustainable Tank Cultivation of the Red Edible Seaweed Porphyra. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696527.bard.

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Porphyra species (commonly known as ‘nori’ or ‘purple laver’) are edible red seaweeds rich in proteins, vitamins and other highly valued biogenic compounds. For years Porphyra has been cultured using seeded nets extended in the open sea, and its biomass consumed primarily in the Far East. While demands for international markets have increased steadily at an average of 20% per year, supplies are on the verge and not expected to meet future demands. Alternatively, land-based cultivation of seaweed has become attractive in the mariculture industry since (1) important growth parameters can be controlled, (2) is environmentally friendly and (3) perfectly matches with integrated aquaculture leading to sustainable, high quality products. During the last few years a tank cultivation technology for Porphyra has been developed at the Israeli institution. This technology is based on indoor production of asexual spores and their subsequent growth to 1-2 mm seedlings. The seedlings are then transferred to outdoor tanks and ponds when seawater temperatures drop to 20 °C, or below, and days become shorter during winter time. However, the current technology efficiently serves only about 100 m2 of ponds during one growth season. In order to produce seedlings in sufficient amounts, it is critical to address both technical and biological aspects of seedling production, securing optimal up-scale to commercial-size cultivation farms. We hypothesize that massive production of spores is related to thalli origin, thalli age and sporulation triggers, and that seedling survival and their subsequent growth potential is determined by the seawater quality and overall indoor growth conditions imposed. A series of bio-reactors were constructed and tested in which spore release and spore growth were separately studied. The main assessment criteria for optimal viability of the seedlings will be by determining their electron transport rate using PAM fluorometry and by subsequent growth and biomass yields in outdoor ponds. Altogether the project showed (1), controlled sporulation is possible in big outdoor/growth chamber settings provided initial stock material (small frozen seedlings) is at hand, (2), contamination problems can be almost completely avoided if stock material is properly handled (clean as possible and partially dehydrated prior to freezing), (3), spore release can significantly be enhance using high nutrient levels during thawing for P. yezoensis and P. haitanensis, but not for P. rosengurttii, (4), PAM fluorometry is an efficient tool to estimate growth capacity in both seedlings and juvenile thalli. The BARD funding also served to explore other aspects of Porphyra biology and cultivation. For example, the taxonomical status of Porphyra strains used in this study was defined (see appendix), and the potential use of this seaweed in bioremediation was well substantiated. In addition, BARD funding supported a number of opportunities and activities in the Israeli lab, direct or indirectly related to the initial objectives of the project such as: additional molecular work in other seaweeds, description of at least 2 new species for the Israeli Mediterranean, and continuous support for the writing of a book on Global Change and applied aspects of seaweeds. The technology for Porphyra cultivation in land-based ponds is readily available. This study corroborated previous know-how of Porphyra growth in tanks and ponds, and yet offers important improvements regarding seedling production and their handling for successful cultivation. This study supported various other activities opening additional important issues in the biology/cultivation/use of Porphyra and other seaweeds.
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Horwitz, Benjamin A., and Barbara Gillian Turgeon. Fungal Iron Acquisition, Oxidative Stress and Virulence in the Cochliobolus-maize Interaction. United States Department of Agriculture, March 2012. http://dx.doi.org/10.32747/2012.7709885.bard.

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Our project focused on genes for high affinity iron acquisition in Cochliobolus heterostrophus, a necrotrophic pathogen of maize, and their intertwined relationship to oxidative stress status and virulence of the fungus on the host. An intriguing question was why mutants lacking the nonribosomal peptide synthetase (NRPS) gene (NPS6) responsible for synthesis of the extracellular siderophore, coprogen, are sensitive to oxidative stress. Our overall objective was to understand the mechanistic connection between iron stress and oxidative stress as related to virulence of a plant pathogen to its host. The first objective was to examine the interface where small molecule peptide and reactive oxygen species (ROS) mechanisms overlap. The second objective was to determine if the molecular explanation for common function is common signal transduction pathways. These pathways, built around sensor kinases, response regulators, and transcription factors may link sequestering of iron, production of antioxidants, resistance to oxidative stress, and virulence. We tested these hypotheses by genetic manipulation of the pathogen, virulence assays on the host plant, and by following the expression of key fungal genes. An addition to the original program, made in the first year, was to develop, for fungi, a genetically encoded indicator of redox state based on the commercially available Gfp-based probe pHyper, designed for animal cell biology. We implemented several tools including a genetically encoded indicator of redox state, a procedure to grow iron-depleted plants, and constructed a number of new mutants in regulatory genes. Lack of the major Fe acquisition pathways results in an almost completely avirulent phenotype, showing how critical Fe acquisition is for the pathogen to cause disease. Mutants in conserved signaling pathways have normal ability to regulate NPS6 in response to Fe levels, as do mutants in Lae1 and Vel1, two master regulators of gene expression. Vel1 mutants are sensitive to oxidative stress, and the reason may be underexpression of a catalase gene. In nps6 mutants, CAT3 is also underexpressed, perhaps explaining the sensitivity to oxidative stress. We constructed a deletion mutant for the Fe sensor-regulator SreA and found that it is required for down regulation of NPS6 under Fe-replete conditions. Lack of SreA, though, did not make the fungus over-sensitive to ROS, though the mutant had a slow growth rate. This suggests that overproduction of siderophore under Fe-replete conditions is not very damaging. On the other hand, increasing Fe levels protected nps6 mutants from inhibition by ROS, implying that Fe-catalyzed Fenton reactions are not the main factor in its sensitivity to ROS. We have made some progress in understanding why siderophore mutants are sensitive to oxidative stress, and in doing so, defined some novel regulatory relationships. Catalase genes, which are not directly related to siderophore biosynthesis, are underexpressed in nps6 mutants, suggesting that the siderophore product (with or without bound Fe) may act as a signal. Siderophores, therefore, could be a target for intervention in the field, either by supplying an incorrect signal or blocking a signal normally provided during infection. We already know that nps6 mutants cause smaller lesions and have difficulty establishing invasive growth in the host. Lae1 and Vel1 are the first factors shown to regulate both super virulence conferred by T-toxin, and basic pathogenicity, due to unknown factors. The mutants are also altered in oxidative stress responses, key to success in the infection court, asexual and sexual development, essential for fungal dissemination in the field, aerial hyphal growth, and pigment biosynthesis, essential for survival in the field. Mutants in genes encoding NADPH oxidase (Nox) are compromised in development and virulence. Indeed the triple mutant, which should lack all Nox activity, was nearly avirulent. Again, gene expression experiments provided us with initial evidence that superoxide produced by the fungus may be most important as a signal. Blocking oxidant production by the pathogen may be a way to protect the plant host, in interactions with necrotrophs such as C. heterostrophus which seem to thrive in an oxidant environment.
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Propagación asexual en el cultivo del mango. Corporación colombiana de investigación agropecuaria - AGROSAVIA, 2013. http://dx.doi.org/10.21930/agrosavia.video.2013.163.

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En respuesta a la necesidad promover acciones encaminadas a mejorar la calidad y productividad en el cultivo de mango. En este clip tecnológico se dan las recomendaciones para la propagación asexual en el cultivo del mango.
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