Can mechanistic constraints on recombination reestablishment explain the long-term maintenance of degenerate sex chromosomes?use asterix (*) to get italics

Thomas Lenormand, Denis RozePlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"

2024

<p style="text-align: justify;">Y and W chromosomes often stop recombining and degenerate. Most work on recombination suppression has focused on the mechanisms favoring recombination arrest in the short term. Yet, the long-term maintenance of recombination suppression is critical to evolving degenerate sex chromosomes. This long-term maintenance has been little investigated. In the long term, recombination suppression may be maintained for selective reasons (e.g., involving the emergence of nascent dosage compensation), or due to mechanistic constraints preventing the reestablishment of recombination, for instance when complex chromosomal rearrangements evolve on the Y. In this paper, we investigate these "constraint" theories. We show that they face a series of theoretical difficulties: they are not robust to extremely low rates of recombination restoration; they would rather cause population extinction than Y degeneration; they are less efficient at producing a non-recombining and degenerate Y than scenarios adding a selective pressure against recombination, whatever the rate of recombination restoration. Finally, whether such very high constraints exist is questionable. Very low rates of recombination reestablishment are sufficient to prevent Y degeneration, given the large fitness advantage to recover a non-degenerate Y or W for the heterogametic sex. The assumption of a lack of genetic variation to restore recombination seems also implausible given known mechanisms to restore a recombining pair of sex chromosomes.</p>

https://doi.org/10.5281/zenodo.5504424You should fill this box only if you chose 'Codes have been used in this study'. URL must start with http:// or https://

sex chromosome, recombination, degeneration, inversion, dosage compensation, theory

NonePlease indicate the methods that may require specialised expertise during the peer review process (use a comma to separate various required expertises).

Evolutionary Theory, Genome Evolution, Population Genetics / Genomics, Reproduction and Sex

Pavitra Muralidhar [pmuralidhar@ucdavis.edu], Ubeda, Francisco [f.ubeda@rhul.ac.uk], Wen-Juan Ma [Wen-Juan.Ma@vub.be], Stephen Wright [stephen.wright@utoronto.ca], Aneil Agrawal [a.agrawal@utoronto.ca], Aneil F. Agrawal suggested: Sally Otto

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Tatiana Giraud [tatiana.giraud@u-psud.fr], Paul Jay [paul.yann.jay@gmail.com], Deborah Charlesworth [Deborah.Charlesworth@ed.ac.uk], Colin Olito [colin.olito@biol.lu.se]e.g. John Doe john@doe.com

2023-10-27 21:52:06

Jos Käfer