Genetic Differentiation by Sexual Conflict

Abstract

Sexual conflict has been suggested as a general cause of genetic diversification in reproductive characters, and as a possible cause of speciation. We use individual-based simulations to study the dynamics of sexual conflict in an isolated diploid population with no spatial structure. To explore the effects of genetic details, we consider two different types of interlocus interaction between female and male traits, and three different types of intra-locus interaction. In the simulations, sexual conflict resulted in at least the following five regimes: (1) continuous coevolutionary chase, (2) evolution toward an equilibrium, (3) cyclic coevolution, (4) extensive genetic differentiation in female traits/genes only, and (5) extensive genetic differentiation in both male and female traits/genes. Genetic differentiation was hardly observed when the traits involved in reproduction were determined additively and interacted in a trait-by-trait way. When the traits interacted in a component-by-component way, genetic differentiation was frequently observed under relatively broad conditions. The likelihood of genetic differentiation largely depended on the number of loci and the type of within-locus dominance. With multiple loci per trait, genetic differentiation was often observed but sympatric speciation was typically hindered by recombination. Sympatric speciation was possible but only under restrictive conditions. Our simulations also highlight the importance of stochastic effects in the dynamics of sexual conflict.

Homosexuality as a Consequence of Epigenetically Canalized Sexual Development

“…It has been shown to significantly affect or drive a number of biological phenomena and processes, including survival and fertility (Rice 1996), mate choice (Gavrilets et al 2001), genetic differentiation (Hayashi et al 2007), reproductive isolation (Gavrilets 2000) and speciation (Parker and Partridge 1998;Gavrilets and Waxman 2002;Gavrilets and Hayashi 2005), sex chromosome evolution (Rice et al 2008), sib competition (Rice et al 2009), maternal selection (Miller et al 2006), and grandparental care ). This paper argues that sexually antagonistic selection can also be involved in epigenetic effects and explain the enigmatic high prevalence of several fitness-reducing human characters.…”

Speciation through evolution of sex-linked genes

“…Apart from isolation through species-specific ecological habits (for example, Via, 2001), interbreeding may also be prevented through divergence of primary sexual organs. Primary sex organs may evolve in response to both natural and sexual selection, including components of sexually antagonistic selection causing rapid evolution and divergence (Gavrilets, 2000;Arnqvist and Rowe, 2004;Hayashi et al, 2007). Finally, postmating prezygotic isolation may arise through divergence of reproductive proteins, which are involved in gamete recognition systems preceding the fusion of gametes.…”

Female polymorphisms, sexual conflict and limits to speciation processes in animals

“…The genetic architecture includes the number of loci, their specific effects and dominance relationships between alleles (Hayashi et al 2007) and the strength of assortative mating and the resulting linkage disequilibria between male and female trait alleles (Hardling and Bergsten 2006).…”