Hastings A, Hom C L
Department of Mathematics, University of California, Davis 95616.
Genetics. 1989 Jun;122(2):459-63. doi: 10.1093/genetics/122.2.459.
We demonstrate that, in a model incorporating weak Gaussian stabilizing selection on n additively determined characters, at most n loci are polymorphic at a stable equilibrium. The number of characters is defined to be the number of independent components in the Gaussian selection scheme. We also assume linkage equilibrium, and that either the number of loci is large enough that the phenotypic distribution in the population can be approximated as multivariate Gaussian or that selection is weak enough that the mean fitness of the population can be approximated using only the mean and the variance of the characters in the population. Our results appear to rule out antagonistic pleiotropy without epistasis as a major force in maintaining additive genetic variation in a uniform environment. However, they are consistent with the maintenance of variability by genotype-environment interaction if a trait in different environments corresponds to different characters and the number of different environments exceeds the number of polymorphic loci that affect the trait.
我们证明，在一个对n个加性决定性状进行弱高斯稳定选择的模型中，在稳定平衡状态下，最多有n个基因座是多态的。性状的数量被定义为高斯选择方案中的独立成分数量。我们还假设连锁平衡，并且要么基因座数量足够多，使得种群中的表型分布可以近似为多元高斯分布，要么选择足够弱，使得种群的平均适合度可以仅使用种群中性状的均值和方差来近似。我们的结果似乎排除了没有上位性的拮抗多效性作为在均匀环境中维持加性遗传变异的主要力量。然而，如果一个性状在不同环境中对应于不同的性状，并且不同环境的数量超过影响该性状的多态基因座的数量，那么我们的结果与通过基因型-环境相互作用维持变异性是一致的。
