Matocq M D, Patton J L, da Silva M N
Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley 94720-3160, USA.
Evolution. 2000 Aug;54(4):1423-32. doi: 10.1111/j.0014-3820.2000.tb00574.x.
Population history and current demographic and ecological factors determine the amount of genetic variation within and the degree of differentiation among populations. Differences in the life history and ecology of codistributed species may lead to differences in hierarchical population genetic structure. Here, we compare patterns of genetic diversity and structure of two species of spiny rats in the genus Proechimys from the Rio Jurui of western Amazonian Brazil. Based on the ecological and life-history differences between the two species, we make predictions as to how they might differ in patterns of genetic diversity and structure. We use mitochondrial sequence data from the cytochrome b gene to test these predictions. Although both species maintain nearly the same number of mitochondrial haplotypes across the sampled range, they differ in levels of genetic diversity and geographic structure. Patterns of gene flow are also different between the two species with average M-values of nearly three in P. steerei and less than one in P. simonsi. Our initial predictions are largely upheld by the genetic data and where conflicting hypotheses arise, we suggest further studies that may allow us to distinguish among evolutionary scenarios. Separating the effects of history and ongoing demography on patterns of genetic diversity is challenging. Combining genetic analyses with field studies remains essential to disentangling these complex processes.
种群历史以及当前的人口统计学和生态因素决定了种群内部遗传变异的数量以及种群之间的分化程度。同域分布物种在生活史和生态方面的差异可能导致种群遗传结构层次的差异。在此，我们比较了来自巴西亚马逊西部茹鲁伊河的刺豚鼠属两种刺鼠的遗传多样性模式和结构。基于这两个物种在生态和生活史方面的差异，我们预测它们在遗传多样性模式和结构上可能存在的差异。我们使用细胞色素b基因的线粒体序列数据来检验这些预测。尽管在整个采样范围内，两个物种保持的线粒体单倍型数量几乎相同，但它们在遗传多样性水平和地理结构上存在差异。两个物种之间的基因流模式也不同，斯氏刺豚鼠的平均M值接近3，而西蒙斯刺豚鼠的平均M值小于1。我们最初的预测在很大程度上得到了遗传数据的支持，当出现相互矛盾的假设时，我们建议进行进一步的研究，以便我们能够区分不同的进化情景。区分历史和当前人口统计学对遗传多样性模式的影响具有挑战性。将遗传分析与实地研究相结合对于理清这些复杂过程仍然至关重要。
