Clark A G
Genetics. 1987 Mar;115(3):569-77. doi: 10.1093/genetics/115.3.569.
Several population genetic models allowing natural selection to act on Y-linked polymorphism are examined. The first incorporates pleiotropic effects of a Y-linked locus, such that viability, segregation distortion, fecundity and sexual selection can all be determined by one locus. It is shown that no set of selection parameters can maintain a stable Y-linked polymorphism. Interaction with the X chromosome is allowed in the next model, with viabilities determined by both X- and Y-linked factors. This model allows four fixation equilibria, two equilibria with X polymorphism and a unique point with both X- and Y-linked polymorphism. Stability analysis shows that the complete polymorphism is never stable. When X- and Y-linked loci influence meiotic drive, it is possible to have all fixation equilibria simultaneously unstable, and yet there is no stable interior equilibrium. Only when viability and meiotic drive are jointly affected by both X- and Y-linked genes can a Y-linked polymorphism be maintained. Unusual dynamics, including stable limit cycles, are generated by this model. Numerical simulations show that only a very small portion of the parameter space admits Y polymorphism, a result that is relevant to the interpretation of levels of Y-DNA sequence variation in natural populations.
研究了几种允许自然选择作用于Y连锁多态性的群体遗传模型。第一个模型纳入了一个Y连锁基因座的多效性效应，使得生存力、分离畸变、繁殖力和性选择都可以由一个基因座决定。结果表明，没有一组选择参数能够维持稳定的Y连锁多态性。下一个模型考虑了与X染色体的相互作用，其生存力由X连锁和Y连锁因子共同决定。该模型允许有四个固定平衡，两个具有X多态性的平衡以及一个同时具有X和Y连锁多态性的唯一点。稳定性分析表明，完全多态性从不稳定。当X和Y连锁基因座影响减数分裂驱动时，有可能所有固定平衡同时不稳定，然而却不存在稳定的内部平衡。只有当生存力和减数分裂驱动同时受到X和Y连锁基因的共同影响时，Y连锁多态性才能得以维持。该模型产生了包括稳定极限环在内的异常动态。数值模拟表明，只有极小部分的参数空间允许Y多态性，这一结果与自然种群中Y-DNA序列变异水平的解释相关。
