Genomic Perspectives on the Long-Term Absence of Sexual Reproduction in Animals

2011 ◽  
pp. 223-242 ◽  
Author(s):  
Etienne G. J. Danchin ◽  
Jean-François Flot ◽  
Laetitia Perfus-Barbeoch ◽  
Karine Van Doninck
Keyword(s):  
Sexual Reproduction

scholarly journals Sexual reproduction with variable mating systems can resist asexuality in a rock–paper–scissors dynamics

2015 ◽  
Vol 2 (7) ◽  
pp. 140383 ◽  
Author(s):  
Juan Carranza ◽  
Vicente Polo
Keyword(s):  
Mating System ◽  
Sexual Reproduction ◽  
Parameter Space ◽  
Mating Systems ◽  
Reproductive Mode ◽  
Long Term Effects ◽  
Diploid Population ◽  
Theoretical Question ◽  
Equal Contribution

While sex can be advantageous for a lineage in the long term, we still lack an explanation for its maintenance with the twofold cost per generation. Here we model an infinite diploid population where two autosomal loci determine, respectively, the reproductive mode, sexual versus asexual and the mating system, polygynous (costly sex) versus monogamous (assuming equal contribution of parents to offspring, i.e. non-costly sex). We show that alleles for costly sex can spread when non-costly sexual modes buffer the interaction between asexual and costly sexual strategies, even without twofold benefit of recombination with respect to asexuality. The three interacting strategies have intransitive fitness relationships leading to a rock–paper–scissors dynamics, so that alleles for costly sex cannot be eliminated by asexuals in most situations throughout the parameter space. Our results indicate that sexual lineages with variable mating systems can resist the invasion of asexuals and allow for long-term effects to accumulate, thus providing a solution to the persisting theoretical question of why sex was not displaced by asexuality along evolution.

Mating type segregation in Choanephora cucurbitarum following sexual reproduction

1996 ◽  
Vol 74 (6) ◽  
pp. 919-923 ◽  
Author(s):  
M. Q. Yu ◽  
W. H. Ko
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Long Term Storage ◽  
Respective Parent ◽  
Choanephora Cucurbitarum ◽  
The Cross ◽  
Term Storage ◽  
Hyphal Fragment

Zygospore progeny from the cross between + and − isolates of Choanephora cucurbitarum consisted of +, −, and ± types. The + and − zygospore isolates were stable, giving rise to hyphal fragment cultures and sporangiospores with the same mating type as their respective parent. However, the ± zygospore isolates were unstable, segregating to +, −, and ± types during asexual propagations. During long-term storage, the + and − isolates were also very stable, but ± isolates were not. All the ± isolates originating from single zygospores, hyphal fragments, or sporangiospores produced azygospores, suggesting that azygospores of this fungus are produced by mating-type heterokaryotic mycelia. Keywords: azygospore, Choanephora cucurbitarum, germsporangiospore, germsporangium, zygospore germination.

Genomic Signature of Sexual Reproduction in the Bdelloid Rotifer Macrotrachella quadricornifera

Genetics ◽  
2021 ◽  
Author(s):  
Veronika N Laine ◽  
Timothy Sackton ◽  
Matthew Meselson
Keyword(s):  
Sexual Reproduction ◽  
Genomic Signature ◽  
Allele Sharing ◽  
Bdelloid Rotifer ◽  
Freshwater Invertebrates ◽  
Bdelloid Rotifers ◽  
Worldwide Distribution

Abstract Bdelloid rotifers, common freshwater invertebrates of ancient origin and worldwide distribution have long been thought to be entirely asexual, being the principal exception to the view that in eukaryotes the loss of sex leads to early extinction. That bdelloids are facultatively sexual is shown by a study of allele sharing within a group of closely related bdelloids of the species Macrotrachella quadricornifera, supporting the view that sexual reproduction is essential for long-term success in all eukaryotes.

scholarly journals Condition-dependent sex: who does it, when and why?

2016 ◽  
Vol 371 (1706) ◽  
pp. 20150539 ◽  
Author(s):  
Yoav Ram ◽  
Lilach Hadany
Keyword(s):  
Theoretical Prediction ◽  
Sexual Reproduction ◽  
Term Survival ◽  
Long Term Survival ◽  
Poor Condition ◽  
Empirical Results ◽  
Wide Range ◽  
Negative Condition

We review the phenomenon of condition-dependent sex—where individuals' condition affects the likelihood that they will reproduce sexually rather than asexually. In recent years, condition-dependent sex has been studied both theoretically and empirically. Empirical results in microbes, fungi and plants support the theoretical prediction that negative condition-dependent sex, in which individuals in poor condition are more likely to reproduce sexually, can be evolutionarily advantageous under a wide range of settings. Here, we review the evidence for condition-dependent sex and its potential implications for the long-term survival and adaptability of populations. We conclude by asking why condition-dependent sex is not more commonly observed, and by considering generalizations of condition-dependent sex that might apply even for obligate sexuals. This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’.

Half a Man

2017 ◽  
Author(s):  
Beth Linker ◽  
Whitney E. Laemmli
Keyword(s):  
World War Ii ◽  
Sexual Reproduction ◽  
The United States ◽  
Male Sexuality ◽  
Postwar Period ◽  
Sexual Performance ◽  
World War ◽  
World War Ii Veterans ◽  
History Of

At the conclusion of World War II, more than 600,000 men returned to the United States with long-term disabilities, profoundly destabilizing male sexuality in America. This chapter excavates the contours of that change and its attendant anxieties in order to broaden scholarly interpretations of sexuality in the postwar period. Ultimately, the chapter shows that, although sexual reproduction is often coded female and sexual performance male, such a popularly held binary does not hold true when it comes to the history of paraplegic World War II veterans. To these veterans, and to the medical men who treated them, sexual reproduction became the ultimate signifier of remasculinization.

scholarly journals Sexual Reproduction in Bdelloid Rotifers

2020 ◽  
Author(s):  
Veronika N. Laine ◽  
Timothy Sackton ◽  
Matthew Meselson
Keyword(s):  
Sexual Reproduction ◽  
Allele Sharing ◽  
Evolution Theory ◽  
Epistatic Interactions ◽  
Bdelloid Rotifers ◽  
Genome Wide ◽  
Growing Body ◽  
Macrotrachela Quadricornifera ◽  
Evolutionary Success

ABSTRACTNearly all eukaryotes reproduce sexually, either constitutively or facultatively, and nearly all that are thought to be asexual arose recently from sexuals, suggesting that loss of sex leads to early extinction. In apparent exception, there are several groups of ancient origin that have been thought to be entirely asexual. Of these, the most extensively studied are the rotifers of Class Bdelloidea. Yet the evidence for their asexuality is entirely negative -- the failure to establish the existence of males or hermaphrodites. Nevertheless, there is a growing body of evidence that bdelloids do reproduce sexually, albeit rarely, retaining meiosis-associated genes and, in a limited study of allele sharing in the bdelloid Macrotrachela quadricornifera, displaying a pattern of genetic exchange indicating recent sexual reproduction. Here we present a much larger study of allele sharing in the same system, clearly showing the occurrence of sexual reproduction, thereby removing the principal challenge to the generalization that sexual reproduction is essential for long-term evolutionary success in eukaryotes. We also discuss the relation between bdelloid life history and population structure and a possible benefit of outcrossing in restoring beneficial genome-wide epistatic interactions disrupted by loss of heterozygosity.STATEMENT OF SIGNIFICANCEMany hypotheses have been advanced to explain why, despite its substantial costs, sexual reproduction is nearly universal in eukaryotes and why the loss of sex generally leads to early extinction--a major problem in current evolution theory. Posing a challenge to all such hypotheses are a few groups of ancient origin that have been thought to be entirely asexual. Of these, the most extensively studied are the rotifers of Class Bdelloidea. Here we show that a bdelloid species is facultatively sexual, removing what had been a long-standing challenge to hypotheses for the benefit of sex. We also suggest that genome-wide beneficial epistasis may contribute to the advantage of sex over asex in diploids and to the predominance of diploidy over haploidy in eukaryotes.

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