Department of Zoology, NJ-15, University of Washington, Seattle, Washington 98195.
Genetics. 1985 Feb;109(2):441-57. doi: 10.1093/genetics/109.2.441.
Use of sequence information from extranuclear genomes to examine deme structure in natural populations has been hampered by lack of clear linkage between sequence relatedness and rates of mutation and migration among demes. Here, we approach this problem in two complementary ways. First, we develop a model of extranuclear genomes in a population divided into a finite number of demes. Sex-dependent migration, neutral mutation, unequal genetic contribution of separate sexes and random genetic drift in each deme are incorporated for generality. From this model, we derive the relationship between gene identity probabilities (between and within demes) and migration rate, mutation rate and effective deme size. Second, we show how within- and between-deme identity probabilities may be calculated from restriction maps of mitochondrial (mt) DNA. These results, when coupled with our results on gene flow and genetic differentiation, allow estimation of relative interdeme gene flow when deme sizes are constant and genetic variants are selectively neutral. We illustrate use of our results by reanalyzing published data on mtDNA in mouse populations from around the world and show that their geographic differentiation is consistent with an island model of deme structure.
利用核外基因组的序列信息来研究自然种群的居群结构，一直受到序列相关性与居群间突变和迁移速率之间缺乏明确联系的阻碍。在这里，我们通过两种互补的方法来解决这个问题。首先，我们建立了一个在有限数量的居群中划分的种群的核外基因组模型。为了通用性，模型中包含了性依赖的迁移、中性突变、雌雄个体遗传贡献的不平等以及每个居群中的随机遗传漂变。从这个模型中，我们推导出了居群间和居群内基因同一性概率（基因相同的概率）与迁移率、突变率和有效居群大小之间的关系。其次，我们展示了如何从线粒体（mt）DNA 的限制图谱中计算居群内和居群间的同一性概率。这些结果，与我们关于基因流动和遗传分化的结果相结合，允许在居群大小不变且遗传变异是选择性中性的情况下，估计相对的居群间基因流动。我们通过重新分析来自世界各地的老鼠种群的 mtDNA 的已发表数据来演示我们的结果的用途，并表明它们的地理分化与居群结构的岛屿模型一致。
