Lehmann Laurent, Keller Lukas F, Kokko Hanna
Laboratory of Ecological and Evolutionary Dynamic, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
J Theor Biol. 2007 Jan 21;244(2):282-95. doi: 10.1016/j.jtbi.2006.07.033. Epub 2006 Aug 12.
Female mate choice influences the maintenance of genetic variation by altering the mating success of males with different genotypes. The evolution of preferences themselves, on the other hand, depends on genetic variation present in the population. Few models have tracked this feedback between a choice gene and its effects on genetic variation, in particular when genes that determine offspring viability and attractiveness have dominance effects. Here we build a population genetic model that allows comparing the evolution of various choice rules in a single framework. We first consider preferences for good genes and show that focused preferences for homozygotes evolve more easily than broad preferences, which allow heterozygous males high mating success too. This occurs despite better maintenance of genetic diversity in the latter scenario, and we discuss why empirical findings of superior mating success of heterozygous males consequently do not immediately lead to a better understanding of the lek paradox. Our results thus suggest that the mechanisms that help maintain genetic diversity also have a flipside of making female choice an inaccurate means of producing the desired kind of offspring. We then consider preferences for heterozygosity per se, and show that these evolve only under very special conditions. Choice for compatible genotypes can evolve but its selective advantage diminishes quickly due to frequency-dependent selection. Finally, we show that our model reproduces earlier results on selfing, when the female choice strategy produces assortative mating. Overall, our model indicates that various forms of heterozygote-favouring (or variable) female choice pose a problem for the theory of sexual ornamentation based on indirect benefits, rather than a solution.
雌性配偶选择通过改变不同基因型雄性的交配成功率来影响遗传变异的维持。另一方面，偏好本身的进化取决于种群中存在的遗传变异。很少有模型追踪选择基因与其对遗传变异的影响之间的这种反馈，特别是当决定后代生存能力和吸引力的基因具有显性效应时。在这里，我们构建了一个种群遗传模型，以便在单一框架内比较各种选择规则的进化。我们首先考虑对优质基因的偏好，并表明对纯合子的集中偏好比广泛偏好更容易进化，广泛偏好也会使杂合子雄性获得较高的交配成功率。尽管在后一种情况下遗传多样性得到了更好的维持，但仍会出现这种情况，我们讨论了为什么杂合子雄性交配成功率更高的实证结果并不能立即让我们更好地理解“lek悖论”。因此，我们的结果表明，有助于维持遗传多样性的机制也有其反面，即会使雌性选择成为产生理想后代类型的不准确方式。然后，我们考虑对杂合性本身的偏好，并表明这些偏好仅在非常特殊的条件下才会进化。对兼容基因型的选择可以进化，但其选择优势由于频率依赖选择而迅速减弱。最后，我们表明，当雌性选择策略产生选型交配时，我们的模型重现了早期关于自交的结果。总体而言，我们的模型表明，各种形式的杂合子偏好（或可变）雌性选择给基于间接利益的性装饰理论带来了问题，而不是解决方案。
