Guerrero Rafael F, Kirkpatrick Mark
Department of Integrative Biology C-0990, University of Texas, Austin, Texas, 78712.
Evolution. 2014 Oct;68(10):2747-56. doi: 10.1111/evo.12481. Epub 2014 Aug 1.
We use forward and coalescent models of population genetics to study chromosome fusions that reduce the recombination between two locally adapted loci. Under a continent-island model, a fusion spreads and reaches a polymorphic equilibrium when it causes recombination between locally adapted alleles to be less than their selective advantage. In contrast, fusions in a two-deme model always spread; whether it reaches a polymorphic equilibrium or becomes fixed depends on the relative recombination rates of fused homozygotes and heterozygotes. Neutral divergence around fusion polymorphisms is markedly increased, showing peaks at the point of fusion and at the locally adapted loci. Local adaptation could explain the evolution of many of chromosome fusions, which are some of the most common chromosome rearrangements in nature.
我们运用群体遗传学的正向和溯祖模型来研究染色体融合，这些融合会减少两个局部适应位点之间的重组。在大陆 - 岛屿模型下，当融合导致局部适应等位基因之间的重组小于其选择优势时，融合会扩散并达到多态平衡。相比之下，在双亚群模型中，融合总是会扩散；它是否达到多态平衡或固定取决于融合纯合子和杂合子的相对重组率。融合多态性周围的中性分歧显著增加，在融合点和局部适应位点处出现峰值。局部适应可以解释许多染色体融合的进化，而染色体融合是自然界中一些最常见的染色体重排。
