Gene identity and genetic differentiation of populations in the finite island model.
Gene identity and genetic differentiation of populations in the finite island model.
复制标题
有限岛模型中种群的基因同一性和遗传分化。
作者：
N. Takahata
对于中性突变的情况，利用扩散近似推导出了细分群体中基因频率变化的基因同一性(纯合性)的方差公式。结果表明，当基因流极小时，平衡状态下整个种群的基因同一性的方差小于具有相同平均基因同一性的泛种群的基因同一性的方差。另一方面，尽管大量的基因流动使细分的种群等同于泛种群，但存在一个中间范围的基因流动，在这个区间内，种群细分可以增加方差。这一增加是由于群体间的差异增加所致。在这种情况下，每个群体都有一个优势等位基因，但优势类型可能因群体而异。获得方差的公式使我们能够研究诸如基因分化系数和杂合度相关性等统计量。计算机模拟被用来研究基因同一性的分布以及检验解析公式的有效性。通过仿真研究了选择的效果。
A formula for the variance of gene identity (homozygosity) was derived for the case of neutral mutations using diffusion approximations for the changes of gene frequencies in a subdivided population. It is shown that when gene flow is extremely small, the variance of gene identity for the entire population at equilibrium is smaller than that of the panmictic population with the same mean gene identity. On the other hand, although a large amount of gene flow makes a subdivided population equivalent to a panmictic population, there is an intermediate range of gene flow in which population subdivision can increase the variance. This increase results from the increased variance between colonies. In such a case, each colony has a predominant allele, but the predominant type may differ from colony to colony. The formula for obtaining the variance allows us to study such statistics as the coefficient of gene differentiation and the correlation of heterozygosity. Computer simulations were conducted to study the distribution of gene identity as well as to check the validity of the analytical formulas. Effects of selection were also studied by simulations.