Tazzyman S J, Abbott J K
Theoretical Biology Group, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.
J Evol Biol. 2015 Mar;28(3):723-9. doi: 10.1111/jeb.12592. Epub 2015 Mar 2.
Sexual antagonism occurs when there is a positive intersexual genetic correlation in trait expression but opposite fitness effects of the trait(s) in males and females. As such, it constrains the evolution of sexual dimorphism and may therefore have implications for adaptive evolution. There is currently considerable evidence for the existence of sexually antagonistic genetic variation in laboratory and natural populations, but how sexual antagonism interacts with other evolutionary phenomena is still poorly understood in many cases. Here, we explore how self-fertilization and inbreeding affect the maintenance of polymorphism for sexually antagonistic loci. We expected a priori that selfing should reduce the region of polymorphism, as inbreeding reduces the frequency of heterozygotes and speeds fixation. This expectation was supported, but although previous results suggest that the more an allele that is deleterious to one sex is dominant in that sex, the smaller the region of parameter space that will admit polymorphism, we found that this effect is weakened by self-fertilization. However, the effect of inbreeding is not strong enough to completely cancel out the effect of dominance: For a given frequency of inbreeding, it will still be the case that the more dominant the alleles are in their deleterious context, the smaller the region of parameter space in which they can exist at polymorphism.
当性状表达中存在正的两性间遗传相关性，但该性状在雄性和雌性中的适合度效应相反时，就会发生性拮抗。因此，它限制了两性异形的进化，可能因此对适应性进化产生影响。目前有大量证据表明，在实验室和自然种群中存在性拮抗遗传变异，但在许多情况下，性拮抗如何与其他进化现象相互作用仍知之甚少。在这里，我们探讨自交和近亲繁殖如何影响性拮抗基因座多态性的维持。我们先验地预期自交应该会减少多态性区域，因为近亲繁殖会降低杂合子频率并加速固定。这一预期得到了支持，但是尽管先前的结果表明，对某一性别有害的等位基因在该性别中越显性，允许多态性的参数空间区域就越小，但我们发现自交会削弱这种效应。然而，近亲繁殖的影响不够强大，无法完全抵消显性效应：对于给定的近亲繁殖频率，仍然会出现这样的情况，即在其有害背景下等位基因越显性，它们能够以多态性存在的参数空间区域就越小。
