无限种群中的遗传漂变。伪搭便车模型。
Genetic drift in an infinite population. The pseudohitchhiking model.
作者信息
Gillespie J H
机构信息
Section of Evolution and Ecology, University of California, Davis 95616, USA.
出版信息
Genetics. 2000 Jun;155(2):909-19. doi: 10.1093/genetics/155.2.909.
Selected substitutions at one locus can induce stochastic dynamics that resemble genetic drift at a closely linked neutral locus. The pseudohitchhiking model is a one-locus model that approximates these effects and can be used to describe the major consequences of linked selection. As the changes in neutral allele frequencies when hitchhiking are rapid, diffusion theory is not appropriate for studying neutral dynamics. A stationary distribution and some results on substitution processes are presented that use the theory of continuous-time Markov processes with discontinuous sample paths. The coalescent of the pseudohitchhiking model is shown to have a random number of branches at each node, which leads to a frequency spectrum that is different from that of the equilibrium neutral model. If genetic draft, the name given to these induced stochastic effects, is a more important stochastic force than genetic drift, then a number of paradoxes that have plagued population genetics disappear.
一个位点上的特定替换可以引发随机动态，这种动态类似于紧密连锁的中性位点上的遗传漂变。伪搭便车模型是一个一位点模型，它近似这些效应，可用于描述连锁选择的主要后果。由于搭便车时中性等位基因频率的变化很快，扩散理论不适用于研究中性动态。本文给出了一个平稳分布以及一些关于替换过程的结果，这些结果运用了具有不连续样本路径的连续时间马尔可夫过程理论。伪搭便车模型的溯祖过程在每个节点处显示有随机数量的分支，这导致了一个与平衡中性模型不同的频率谱。如果基因草案（赋予这些诱导随机效应的名称）是比遗传漂变更重要的随机力量，那么困扰群体遗传学的许多悖论就会消失。
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