Paetkau D, Waits L P, Clarkson P L, Craighead L, Strobeck C
Department of Biological Sciences, University of Alberta, Edmonton, Canada.
Genetics. 1997 Dec;147(4):1943-57. doi: 10.1093/genetics/147.4.1943.
A large microsatellite data set from three species of bear (Ursidae) was used to empirically test the performance of six genetic distance measures in resolving relationships at a variety of scales ranging from adjacent areas in a continuous distribution to species that diverged several million years ago. At the finest scale, while some distance measures performed extremely well, statistics developed specifically to accommodate the mutational processes of microsatellites performed relatively poorly, presumably because of the relatively higher variance of these statistics. At the other extreme, no statistic was able to resolve the close sister relationship of polar bears and brown bears from more distantly related pairs of species. This failure is most likely due to constraints on allele distributions at microsatellite loci. At intermediate scales, both within continuous distributions and in comparisons to insular populations of late Pleistocene origin, it was not possible to define the point where linearity was lost for each of the statistics, except that it is clearly lost after relatively short periods of independent evolution. All of the statistics were affected by the amount of genetic diversity within the populations being compared, significantly complicating the interpretation of genetic distance data.
利用来自三种熊（熊科）的大量微卫星数据集，对六种遗传距离测量方法在解决从连续分布中的相邻区域到数百万年前分化的物种等各种尺度关系方面的性能进行了实证检验。在最精细的尺度上，虽然一些距离测量方法表现极佳，但专门为适应微卫星突变过程而开发的统计方法表现相对较差，推测是因为这些统计方法的方差相对较高。在另一个极端，没有任何统计方法能够从关系较远的物种对中分辨出北极熊和棕熊的近亲姐妹关系。这种失败很可能是由于微卫星位点上等位基因分布的限制。在中等尺度上，无论是在连续分布内还是与晚更新世起源的岛屿种群进行比较时，除了在相对较短的独立进化期后线性关系明显丧失外，无法为每种统计方法确定线性关系丧失的点。所有统计方法都受到所比较种群内遗传多样性数量的影响，这使得遗传距离数据的解释变得极为复杂。
