Mitchell-Olds Thomas
Departments of Botany and Genetics, University of Wisconsin, Madison, WI, 53706.
Evolution. 1986 Jan;40(1):107-116. doi: 10.1111/j.1558-5646.1986.tb05722.x.
When variation in life-history characters is caused by many genes of small effect, then quantitative-genetic parameters may quantify constraints on rate and direction of microevolutionary change. I estimated heritabilities and genetic correlations for 16 life-history and morphological characters in two populations of Impatiens capensis, a partially self-pollinating herbaceous annual. The Madison population had little or no additive genetic variance for any of these characters, while the Milwaukee population had significant narrowsense heritabilities and genetic correlations for several traits, including adult size, which is highly correlated with fitness. All genetic correlations among fitness components were positive, hence there is no evidence for antagonistic pleiotropy among these traits. Dissimilarity of heritabilities in the two populations supports theoretical predictions that long-term changes in genetic variance-covariance patterns may occur when population sizes are small and selection is strong, as may occur in many plant species.
当生活史特征的变异由许多效应较小的基因引起时，数量遗传参数可能会量化对微观进化变化速率和方向的限制。我估计了凤仙花（一种部分自花授粉的一年生草本植物）两个种群中16个生活史和形态特征的遗传力和遗传相关性。麦迪逊种群的这些特征几乎没有或没有加性遗传方差，而密尔沃基种群的几个性状，包括与适合度高度相关的成年大小，具有显著的狭义遗传力和遗传相关性。适合度成分之间的所有遗传相关性都是正的，因此没有证据表明这些性状之间存在拮抗多效性。两个种群遗传力的差异支持了理论预测，即当种群规模较小且选择强烈时，遗传方差-协方差模式可能会发生长期变化，许多植物物种可能会出现这种情况。
