Speciation and Sexual Conflict

Abstract

We review mathematical models that explicitly consider the dynamics of evolutionary change driven by sexual conflict over mating rate when males are selected for increasing mating success whereas females are selected to restrict mating rate. These models focus on a pair of traits each of which is controlled by a separate set of genes expressed in one sex only. The traits control the probability of mating and/or fertilization. Overall, there are at least six different dynamic regimes observed in models of sexual conflict: (1) continuous coevolutionary chase between the sexes (which can result in allopatric speciation as a byproduct), (2) evolution towards an equilibrium, (3) cyclic evolution, (4) evolution towards a line of equilibria with subsequent random drift along this line, (5) Buridan's Ass regime involving extensive diversification in female alleles without comparable diversification in male alleles, and (6) extensive diversification in both male and female alleles (which can result in sympatric speciation). Mathematical models also show that different dynamic regimes can be observed with the same set of parameter values but under different initial conditions. It is also possible that the same population switches from one regime to another as a result of stochastic perturbations due to, say, random genetic drift. Moreover, different sets of loci controlling mating and fertilization in the same species can follow different dynamic regimes. We attempt to make some generalizations and identify important directions for theoretical and empirical work.

The dynamics of two- and three-way sexual conflicts over mating

“…These results represent a generalization of those in Gavrilets et al (2001;see also Gavrilets & Waxman 2002;Rowe et al 2003 and a review of similar models in Gavrilets & Hayashi 2005) for the case of more general functions j and w f . Other generalizations have also been explored.…”

“…Their results (see also Frank 2000;Haygood 2004) have demonstrated the possibility of the maintenance of extensive genetic variation in female loci only or in both male and female loci. Numerical individual-based simulations of Gavrilets & Hayashi (2005) explicitly accounting for random genetic drift confirmed the generality of the conclusions based on simple analytical approximations.…”

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 and the evolution of gamete recognition genes: pattern and process

“…Evolutionary theory has suggested several possible mechanisms for these evolutionary patterns, including direction selection for sperm competitive ability, sexual selection, male-female conflict and reinforcement (Wu, 1986;Gavrilets and Waxman, 2002;Gavrilets and Hayashi, 2005). These possibilities have been explored with fertilization experiments, analysis of coalescence patterns, models and comparison of molecular gene sequences within and between species.…”

“…These mechanisms can be species specific or quite general among taxa (Vieira and Miller, 2006). Because basic fertilization demands the interaction of proteins produced by male and female genomes, it can be driven by evolutionary pressures that act on mating systems such as gender conflict (Gavrilets and Waxman, 2002;Gavrilets and Hayashi, 2005;Tomaiuolo et al, 2007), reinforcement (Geyer and Palumbi, 2003) or other aspects of the evolution of reproductive isolation (Tomaiuolo et al, 2007). Because gamete recognition involves relatively few gene products, as opposed to more complex mating barriers in fish and many terrestrial animals, the evolutionary pressures that act to cause reproductive isolation may be more obvious in these simple genetic systems (Palumbi, 1992).…”