Goodnight C J
Department of Biology, University of Vermont, Burlington 05405-0086, USA.
Heredity (Edinb). 2000 May;84 ( Pt 5):587-98. doi: 10.1046/j.1365-2540.2000.00698.x.
Genetic population differentiation is typically viewed as differentiation of population means. However, several theories of evolution and speciation postulate that populations differentiate not only with respect to the population means, but also with respect to the effects of alleles within these populations. I develop herein a measure of population differentiation for the 'local average effects' of alleles, where local average effect is defined as the average effect of an allele in a deme measured as a deviation from the metapopulation mean. The differentiation for local average effects has two components, a component attributable to the population mean and a residual component that is attributable to changes in the local average effects independent of the population mean. The variance in local average effects attributable to the population mean is measured as the variance in the mean local average effect of all alleles. The variance in the residual local average effects is measured as the difference between the variance local average effects of individual alleles and the variance in the mean local average effects of all alleles. Differentiation for population means and differentiation for residual local average effects need not be related. I show that when there is only additive gene action, populations can differentiate for population means, but not for residual local average effects. However, if there is gene interaction then populations can also differentiate for local average effects of alleles. The consequence of this differentiation is that the local average effects of alleles change relative to each other such that an allele that is favoured by selection in one population may be removed by selection in other populations. I discuss the evolutionary consequences of differentiation for local average effects, and the interpretation of QTL data in light of this model.
遗传种群分化通常被视为种群均值的分化。然而，一些进化和物种形成理论假定，种群不仅在种群均值方面存在分化，而且在这些种群中等位基因的效应方面也存在分化。在此，我针对等位基因的“局部平均效应”开发了一种种群分化度量方法，其中局部平均效应被定义为一个deme中一个等位基因的平均效应，以相对于集合种群均值的偏差来衡量。局部平均效应的分化有两个组成部分，一个可归因于种群均值的部分，以及一个剩余部分，该剩余部分可归因于独立于种群均值的局部平均效应的变化。可归因于种群均值的局部平均效应的方差被度量为所有等位基因的平均局部平均效应的方差。剩余局部平均效应的方差被度量为单个等位基因的局部平均效应方差与所有等位基因的平均局部平均效应方差之间的差异。种群均值的分化和剩余局部平均效应的分化不一定相关。我表明，当只有加性基因作用时，种群可以在种群均值方面存在分化，但在剩余局部平均效应方面不存在分化。然而，如果存在基因相互作用，那么种群也可以在等位基因的局部平均效应方面存在分化。这种分化的结果是，等位基因的局部平均效应相对于彼此发生变化，使得在一个种群中受到选择青睐的一个等位基因在其他种群中可能会被选择淘汰。我讨论了局部平均效应分化的进化后果，以及根据该模型对QTL数据的解释。
