Evolutionary rates of testes-expressed genes differ in monogamous and promiscuousPeromyscusspecies

Abstract

Reproductive proteins, including those expressed in the testes, are among the fastest evolving proteins across the tree of life. Sexual selection on traits involved in sperm competition is thought to be a primary driver of testes gene evolution and is expected to differ between promiscuous and monogamous species due to intense competition between males to fertilize females in promiscuous lineages and lack thereof in monogamous ones. Here, we employ the rodent genus Peromyscus as a model to explore differences in evolutionary rates between testis-expressed genes of monogamous and promiscuous species. We find candidate genes that may be associated with increased sperm production in promiscuous species and gene ontology categories that show patterns of molecular convergence associated with phenotypic convergence in independently evolved monogamous species. Overall, our results highlight possible molecular correlates of differences in mating system, which can be contextualized in light of expected selective pressures.

The Evolution of Centriole Degradation in Mouse Sperm

“…Reproductive genes evolve faster than other genes due to adaptive diversification associated with sperm competition, cryptic female choice, and sexual conflict (Clark et al, 2006; reviewed in Swanson and Vacquier, 2002). In contrast, genes integral to sperm function evolve faster in monogamous species than in promiscuous species, possibly because of a reduced selective constraint (Gozashti et al, 2021). Because house mice exhibit a high level of gene sequence diversification (Thybert et al, 2018), the above evolutionary factors may result in a shift in the EIR of FAM161A to below 1.00.…”