When sex chromosomes recombine only in the heterogametic sex: heterochiasmy and heterogamety in Hyla tree frogs

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Serval ID
serval:BIB_46DFFD2D0A69
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
When sex chromosomes recombine only in the heterogametic sex: heterochiasmy and heterogamety in Hyla tree frogs
Journal
Molecular Biology and Evolution
Author(s)
Dufresnes C, Brelsford A, Baier F, Perrin N
ISSN
0737-4038 (print)
1537-1719 (electronic)
Publication state
In Press
Peer-reviewed
Oui
Language
english
Abstract
Sex chromosomes are classically predicted to stop recombining in the heterogametic sex, thereby enforcing linkage between sex-determining (SD) and sex-antagonistic (SA) genes. With the same rationale, a pre-existing sex asymmetry in recombination is expected to affect the evolution of heterogamety, e. g. a low rate of male recombination might favor transitions to XY systems, by generating immediate linkage between SD and SA genes. Furthermore, the accumulation of deleterious mutations on non-recombining Y chromosomes should favor XY-to-XY transitions (which discard the decayed Y), but disfavor XY-to-ZW transitions (which fix the decayed Y as an autosome). Like many anuran amphibians, Hyla tree frogs have been shown to display drastic heterochiasmy (males only recombine at chromosome tips) and are typically XY, which seems to fit the above expectations. Instead, here we demonstrate that two species, H. sarda and H. savignyi, share a common ZW system since at least 11 Mya. Surprisingly, the typical pattern of restricted male recombination has been maintained since then, despite female heterogamety. Hence, sex chromosomes recombine freely in ZW females, not in ZZ males. This suggests that heterochiasmy does not constrain heterogamety (and vice versa), and that the role of SA genes in the evolution of sex chromosomes might have been over-emphasized.
Keywords
linkage mapping, recombination, sex-antagonistic genes, sex-chromosome turnover
Create date
01/08/2020 13:05
Last modification date
02/08/2020 6:26
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