Plante Yves, Boag Peter T, White Bradley N
Department of Biology, Queen's University, Kingston, ON, K7L 3N6, CANADA.
Evolution. 1989 Nov;43(7):1522-1537. doi: 10.1111/j.1558-5646.1989.tb02601.x.
We examined mitochondrial-DNA (mtDNA) sequence heterogeneity on four adjacent trapping grids in an island population of meadow voles (Microtus pennsylvanicus) at two different population densities. Four restriction endonucleases revealed 20 different mtDNA composite phenotypes in samples totaling 198 meadow voles. There were significant heterogeneities in the distribution of four common mtDNA composite phenotypes among the four trapping grids, suggesting that there is population subdivision on a fine scale. Genetic distances between grids, mtDNA diversity within grids, and G also varied during the study period. We found a decrease in genetic distance and an increase in diversity when the population density was high and vice versa when the population density was low. When population density was high, the coefficient of gene differentiation was smaller than the same coefficient observed when the population density was low. These changes in population subdivision and diversity are consistent with theoretical expectations of population structure in which effective female population size and dispersal are the critical variables. The data also support the hypothesis of maintenance of mtDNA diversity by population subdivision, rapid population growth rate, and dispersal.
我们在两个不同种群密度下，对某岛屿草甸田鼠（Microtus pennsylvanicus）种群的四个相邻诱捕网格中的线粒体DNA（mtDNA）序列异质性进行了研究。四种限制性内切酶在总共198只草甸田鼠的样本中揭示了20种不同的mtDNA复合表型。在四个诱捕网格中，四种常见mtDNA复合表型的分布存在显著异质性，这表明在小尺度上存在种群细分。在研究期间，网格间的遗传距离、网格内的mtDNA多样性以及G也有所变化。我们发现，当种群密度高时，遗传距离减小，多样性增加；反之，当种群密度低时则相反。当种群密度高时，基因分化系数小于种群密度低时观察到的相同系数。种群细分和多样性的这些变化与种群结构的理论预期一致，在该理论中，有效雌性种群大小和扩散是关键变量。这些数据也支持了通过种群细分、快速种群增长率和扩散来维持mtDNA多样性的假说。
