Chevalet C
Institut National de la Recherche Agronomique, Centre de Recherches de Toulouse, Laboratoire de Génétique Cellulaire, Castanet Tolosan Cedex, 31326, France.
Theor Popul Biol. 2000 Mar;57(2):167-75. doi: 10.1006/tpbi.1999.1440.
Analysis of diversity between populations diverged from an evolutionarily small number of generations cannot be done under the assumption that allele frequencies reflect an equilibrium between genetic drift and mutations. An alternative to analysis through coalescence theory is proposed in this situation by developing analytical approximations. Using a Poisson approximation of its distribution, the expected number of genes from one generation whose copies make up the population after a number of generations characterized by fixation index F can be shown to be approximated by 2/F-1, irrespective of population size, and probabilities of fixation of alleles over a finite period of time can be also approximated. These expressions, which were checked numerically, should make it possible to calculate approximate likelihoods for allele frequency distributions promoted by drift.
对于从进化上少数几代分化而来的群体间多样性分析，不能基于等位基因频率反映遗传漂变与突变之间平衡的假设来进行。在这种情况下，通过开发解析近似法，提出了一种替代基于合并理论的分析方法。利用其分布的泊松近似，可以证明，经过以固定指数F为特征的若干代后，构成群体的一代中基因的预期数量近似为2/F - 1，与群体大小无关，并且在有限时间内等位基因的固定概率也可以近似。这些通过数值检验的表达式应该能够计算由漂变促进的等位基因频率分布的近似似然性。
