Arnqvist Göran, Vellnow Nikolas, Rowe Locke
Animal Ecology, Department of Ecology and Genetics, Uppsala University, SE-752 36 Uppsala, Sweden
Evolutionary Biology, Zoological Institute, University of Basel, CH-4051 Basel, Switzerland.
Proc Biol Sci. 2014 Jul 22;281(1787). doi: 10.1098/rspb.2014.0489.
There is increasing evidence of segregating sexually antagonistic (SA) genetic variation for fitness in laboratory and wild populations, yet the conditions for the maintenance of such variation can be restrictive. Epistatic interactions between genes can contribute to the maintenance of genetic variance in fitness and we suggest that epistasis between SA genes should be pervasive. Here, we explore its effect on SA genetic variation in fitness using a two locus model with negative epistasis. Our results demonstrate that epistasis often increases the parameter space showing polymorphism for SA loci. This is because selection in one locus is affected by allele frequencies at the other, which can act to balance net selection in males and females. Increased linkage between SA loci had more marginal effects. We also show that under some conditions, large portions of the parameter space evolve to a state where male benefit alleles are fixed at one locus and female benefit alleles at the other. This novel effect of epistasis on SA loci, which we term the 'equity effect', may have important effects on population differentiation and may contribute to speciation. More generally, these results support the suggestion that epistasis contributes to population divergence.
越来越多的证据表明，在实验室和野生种群中，存在与适应性相关的性别拮抗（SA）遗传变异的分离现象，然而维持这种变异的条件可能具有局限性。基因之间的上位性相互作用有助于维持适应性的遗传方差，并且我们认为SA基因之间的上位性应该是普遍存在的。在这里，我们使用具有负上位性的双位点模型来探讨其对SA适应性遗传变异的影响。我们的结果表明，上位性通常会增加显示SA位点多态性的参数空间。这是因为一个位点的选择受到另一个位点等位基因频率的影响，这可以起到平衡雄性和雌性净选择的作用。SA位点之间连锁增加的影响较小。我们还表明，在某些条件下，参数空间的很大一部分会进化到一种状态，即雄性受益等位基因在一个位点固定，而雌性受益等位基因在另一个位点固定。上位性对SA位点的这种新效应，我们称之为“公平效应”，可能对种群分化有重要影响，并可能有助于物种形成。更普遍地说，这些结果支持了上位性有助于种群分化的观点。
