Cherry Joshua L
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
Genetics. 2004 Feb;166(2):1105-14. doi: 10.1534/genetics.166.2.1105.
In a subdivided population, the interaction between natural selection and stochastic change in allele frequency is affected by the occurrence of local extinction and subsequent recolonization. The relative importance of selection can be diminished by this additional source of stochastic change in allele frequency. Results are presented for subdivided populations with extinction and recolonization where there is more than one founding allele after extinction, where these may tend to come from the same source deme, where the number of founding alleles is variable or the founders make unequal contributions, and where there is dominance for fitness or local frequency dependence. The behavior of a selected allele in a subdivided population is in all these situations approximately the same as that of an allele with different selection parameters in an unstructured population with a different size. The magnitude of the quantity N(e)s(e), which determines fixation probability in the case of genic selection, is always decreased by extinction and recolonization, so that deleterious alleles are more likely to fix and advantageous alleles less likely to do so. The importance of dominance or frequency dependence is also altered by extinction and recolonization. Computer simulations confirm that the theoretical predictions of both fixation probabilities and mean times to fixation are good approximations.
在一个细分的种群中，自然选择与等位基因频率的随机变化之间的相互作用会受到局部灭绝及随后重新定殖的影响。等位基因频率随机变化的这一额外来源会削弱选择的相对重要性。本文给出了具有灭绝和重新定殖的细分种群的结果，这些种群在灭绝后有多个奠基等位基因，这些等位基因可能倾向于来自同一源种群，奠基等位基因的数量是可变的，或者奠基者的贡献不相等，并且存在适合度显性或局部频率依赖。在所有这些情况下，细分种群中被选择的等位基因的行为与具有不同选择参数的非结构化种群中不同大小的等位基因的行为大致相同。在基因选择情况下决定固定概率的数量N(e)s(e)的大小总是因灭绝和重新定殖而减小，因此有害等位基因更有可能固定，而有利等位基因则不太可能固定。灭绝和重新定殖也会改变显性或频率依赖的重要性。计算机模拟证实，固定概率和平均固定时间的理论预测都是很好的近似值。
