Goldstein D B, Ruiz Linares A, Cavalli-Sforza L L, Feldman M W
Department of Biological Sciences, Stanford University, California 94305.
Genetics. 1995 Jan;139(1):463-71. doi: 10.1093/genetics/139.1.463.
Mutations of alleles at microsatellite loci tend to result in alleles with repeat scores similar to those of the alleles from which they were derived. Therefore the difference in repeat score between alleles carries information about the amount of time that has passed since they shared a common ancestral allele. This information is ignored by genetic distances based on the infinite alleles model. Here we develop a genetic distance based on the stepwise mutation model that includes allelic repeat score. We adapt earlier treatments of the stepwise mutation model to show analytically that the expectation of this distance is a linear function of time. We then use computer simulations to evaluate the overall reliability of this distance and to compare it with allele sharing and Nei's distance. We find that no distance is uniformly superior for all purposes, but that for phylogenetic reconstruction of taxa that are sufficiently diverged, our new distance is preferable.
微卫星位点上等位基因的突变往往会产生重复分数与它们所衍生的等位基因相似的等位基因。因此,等位基因之间重复分数的差异携带了自它们共享一个共同祖先等位基因以来所经过时间的信息。基于无限等位基因模型的遗传距离忽略了这些信息。在这里,我们开发了一种基于逐步突变模型的遗传距离,该模型包含等位基因重复分数。我们采用了早期对逐步突变模型的处理方法,通过分析表明该距离的期望值是时间的线性函数。然后,我们使用计算机模拟来评估该距离的整体可靠性,并将其与等位基因共享和内氏距离进行比较。我们发现,没有一种距离在所有情况下都是普遍优越的,但对于分歧足够大的分类群的系统发育重建,我们的新距离更可取。