Department of Biochemistry and Biophysics, Vilnius University, Lithuania.
Am Nat. 2012 Sep;180(3):388-93. doi: 10.1086/667215. Epub 2012 Jul 23.
Many classic models of speciation incorporate assortative mating based on mating groups, such as plants with different flowering times, and they investigate whether an ecological trait under disruptive natural selection becomes genetically associated with the selectively neutral mating trait. It is well known that this genetic association is potently destroyed by recombination. In this note, we point out a more fundamental difficulty: if a "knife-edge" symmetry assumption of previous models is violated, then the mating trait is no longer neutral and sexual selection eliminates the polymorphism in the mating locus. This result strengthens the growing consensus that magic traits are the more likely route to nonallopatric speciation. We expand the model assuming also ecological selection on the mating trait and investigate the conditions for natural selection to overcome sexual selection and maintain mating polymorphism; we find that the combination of natural and sexual selection can cause also bistability of allele frequencies.
许多经典的物种形成模型都包含基于交配群体的交配选择性，例如具有不同开花时间的植物，它们研究的是在受到破坏性自然选择的生态特征是否与选择性中性的交配特征在基因上相关联。众所周知，这种基因关联会被重组强烈破坏。在本说明中，我们指出了一个更基本的困难：如果违反了先前模型的“刀刃边缘”对称假设，那么交配特征就不再是中性的，性选择会消除交配位点的多态性。这一结果强化了这样一种共识，即神奇特征更有可能是非地理隔离物种形成的途径。我们扩展了假设也对交配特征进行生态选择的模型，并研究了自然选择克服性选择并维持交配多态性的条件；我们发现，自然选择和性选择的组合也可能导致等位基因频率的双稳态。
