Taylor C E, Mitton J B
Genetics. 1974 Mar;76(3):575-85. doi: 10.1093/genetics/76.3.575.
Multiple factor analysis was used to interpret geographical variation of gene frequencies. Allelic frequencies at three loci (two esterase loci, Esr and Esh, and a malic dehydrogenase locus) from ants (Pogonomyrmex barbatus) collected throughout Texas and reported by Johnsonet al. (1969) were reexamined for patterns of correlation with five environmental measurements: mean January temperature, mean July temperature, mean annual precipitation, elevation, and annual growing season. These measurements and the associated gene frequencies at each sampling location were subjected to factor analysis. Variables highly correlated with the same factor were hypothesized to be causally related. Both orthogonal and oblique rotations of the factor solution provided four factors with essentially the same interpretation. Variation at the Esh locus was associated with a continuum from cold-wet to hot-dry. Variation at the Mdh locus and some of that at the Esr locus was related to the severity of winter months. Other allelic frequencies at the Esr locus had high correlations with a third factor which seemed to be independent of the environmental measurements. None of the allelic frequencies had high correlations with the fourth factor which was interpretable as an altitudinal gradient.
多因素分析被用于解释基因频率的地理变异。约翰逊等人（1969年）报告了在得克萨斯州全境采集的蚂蚁（红收获蚁）三个基因座（两个酯酶基因座，Esr和Esh，以及一个苹果酸脱氢酶基因座）的等位基因频率，重新检查这些频率与五个环境测量值的相关模式：一月平均温度、七月平均温度、年平均降水量、海拔和年生长季。对每个采样地点的这些测量值和相关基因频率进行了因子分析。与同一因子高度相关的变量被假定存在因果关系。因子解的正交旋转和斜交旋转都得到了四个因子，其解释基本相同。Esh基因座的变异与从冷湿到干热的连续变化相关。Mdh基因座的变异以及Esr基因座的部分变异与冬季的严酷程度有关。Esr基因座的其他等位基因频率与第三个因子高度相关，这个因子似乎与环境测量值无关。没有等位基因频率与可解释为海拔梯度的第四个因子高度相关。
