SEX REVERSAL: A FOUNTAIN OF YOUTH FOR SEX CHROMOSOMES?
Article first published online: 9 SEP 2009
© 2009 The Author(s). Journal compilation © 2009 The Society for the Study of Evolution
Volume 63, Issue 12, pages 3043–3049, December 2009
How to Cite
Perrin, N. (2009), SEX REVERSAL: A FOUNTAIN OF YOUTH FOR SEX CHROMOSOMES?. Evolution, 63: 3043–3049. doi: 10.1111/j.1558-5646.2009.00837.x
- Issue published online: 19 NOV 2009
- Article first published online: 9 SEP 2009
- Received July 8, 2009Accepted August 20, 2009
- Muller's ratchet;
- sex-antagonistic genes;
- sex determination
Nonrecombining Y chromosomes are expected to degenerate through the progressive accumulation of deleterious mutations. In lower vertebrates, however, most species display homomorphic sex chromosomes. To address this, paradox I propose a role for sex reversal, which occasionally occurs in ectotherms due to the general dependence of physiological processes on temperature. Because sex-specific recombination patterns depend on phenotypic, rather than genotypic sex, homomorphic X and Y chromosomes are expected to recombine in sex-reversed females. These rare events should generate bursts of new Y haplotypes, which will be quickly sorted out by natural or sexual selection. By counteracting Muller's ratchet, this regular purge should prevent the evolutionary decay of Y chromosomes. I review empirical data supporting this suggestion, and propose further investigations for testing it.