O'Brien P
J Math Biol. 1985;22(3):279-91. doi: 10.1007/BF00276486.
A formula is obtained for the probability that two genes at a single locus, sampled at random from a population at time t, are of particular types. The model assumed is a diffusion approximation to a neutral Wright-Fisher model in which mutation is not necessarily symmetric and the population size is a function of time. It is shown that for symmetric mutation in a population undergoing a step-function type bottleneck, homozygosity increases with decreasing population size. A formula is given for the distribution of the number of segregating sites occurring in two randomly sampled sequences of completely linked sites, with general mutation at a site and identical mutation structure between sites. We give similar results for a population of fixed size but for which the mutation rate is a function of time, and not necessarily symmetric. We confirm the intuitively clear effect that increasing the mutation rate decreases homozygosity.
得到了一个公式，用于计算在时间t从一个群体中随机抽取的位于单个位点上的两个基因属于特定类型的概率。所假设的模型是对中性赖特 - 费希尔模型的扩散近似，其中突变不一定是对称的，且群体大小是时间的函数。结果表明，在经历阶跃函数型瓶颈的群体中，对于对称突变，纯合度随着群体大小的减小而增加。给出了一个公式，用于计算在两个完全连锁位点的随机抽样序列中发生的分离位点数量的分布，位点存在一般突变且位点间具有相同的突变结构。对于固定大小的群体，但突变率是时间的函数且不一定对称的情况，我们给出了类似的结果。我们证实了一个直观上明显的效应，即增加突变率会降低纯合度。
