On the potential for extinction by Muller's ratchet in Caenorhabditis elegans.
Laurence Loewe,Asher D. Cutter +1 more
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It is concluded that pure selfing can persist for only short evolutionary intervals, and is expected to lead to extinction within thousands of years for a plausible portion of parameter space.Abstract:
The self-fertile hermaphrodite worm C. elegans is an important model organism for biology, yet little is known about the origin and persistence of the self-fertilizing mode of reproduction in this lineage. Recent work has demonstrated an extraordinary degree of selfing combined with a high deleterious mutation rate in contemporary populations. These observations raise the question as to whether the mutation load might rise to such a degree as to eventually threaten the species with extinction. The potential for such a process to occur would inform our understanding of the time since the origin of self-fertilization in C. elegans history. To address this issue, here we quantify the rate of fitness decline expected to occur via Muller's ratchet for a purely selfing population, using both analytical approximations and globally distributed individual-based simulations from the evolution@home system to compute the rate of deleterious mutation accumulation. Using the best available estimates for parameters of how C. elegans evolves, we conclude that pure selfing can persist for only short evolutionary intervals, and is expected to lead to extinction within thousands of years for a plausible portion of parameter space. Credible lower-bound estimates of nuclear mutation rates do not extend the expected time to extinction much beyond a million years. Thus we conclude that either the extreme self-fertilization implied by current patterns of genetic variation in C. elegans arose relatively recently or that low levels of outcrossing and other factors are key to the persistence of C. elegans into the present day. We also discuss results for the mitochondrial genome and the implications for C. briggsae, a close relative that made the transition to selfing independently of C. elegans.read more
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Mutation load and rapid adaptation favour outcrossing over self-fertilization
TL;DR: It is shown that outcrossing is favoured in populations of Caenorhabditis elegans subject to experimental evolution both under conditions of increased mutation rate and during adaptation to a novel environment.
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Interplay between whole-genome doubling and the accumulation of deleterious alterations in cancer evolution.
Saioa López,Emilia L. Lim,Stuart Horswell,Kerstin Haase,Ariana Huebner,Michelle Dietzen,Thanos P. Mourikis,Thomas B.K. Watkins,Andrew Rowan,Sally M. Dewhurst,Nicolai Juul Birkbak,Nicolai Juul Birkbak,Gareth A. Wilson,Peter Van Loo,Peter Van Loo,Mariam Jamal-Hanjani,Mariam Jamal-Hanjani,Charles Swanton,Nicholas McGranahan +18 more
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Evolution of the Caenorhabditis elegans Genome
TL;DR: This review synthesizes many of the important insights to date in the understanding of genome organization and function that derive from the evolutionary principles made explicit by theoretical population genetics and molecular evolution and highlights fertile areas for future research on unanswered questions in C. elegans genome evolution.
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Insights Into Species Divergence and the Evolution of Hermaphroditism From Fertile Interspecies Hybrids of Caenorhabditis Nematodes
TL;DR: The hybrid genetics of the first Caenorhabditis species pair capable of producing fertile hybrid progeny are described, and the use of backcrosses to render the hybrid genome partial homozygous for C. briggsae alleles did not increase the incidence of selfing or spermatogenesis relative to the F1 generation.
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Outcrossing and the Maintenance of Males within C. elegans Populations
TL;DR: This review explores how genetic, population genomic, and experimental evolution approaches are being used to address the role of males and outcrossing within C. elegans.
References
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