Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, Rua do Matão, 277, Cidade Universitária, São Paulo, SP, CEP 05508-090, Brazil.
Mol Ecol. 2013 Aug;22(15):3996-4013. doi: 10.1111/mec.12361. Epub 2013 Jun 20.
The Atlantic Forest (AF) harbours one of the most diverse vertebrate faunas of the world, including 199 endemic species of birds. Understanding the evolutionary processes behind such diversity has become the focus of many recent, primarily single locus, phylogeographic studies. These studies suggest that isolation in forest refugia may have been a major mechanism promoting diversification, although there is also support for a role of riverine and geotectonic barriers, two sets of hypotheses that can best be tested with multilocus data. Here we combined multilocus data (one mtDNA marker and eight anonymous nuclear loci) from two species of parapatric antbirds, Myrmeciza loricata and M. squamosa, and Approximate Bayesian Computation to determine whether isolation in refugia explains current patterns of genetic variation and their status as independent evolutionary units. Patterns of population structure, differences in intraspecific levels of divergence and coalescent estimates of historical demography fit the predictions of a recently proposed model of refuge isolation in which climatic stability in the northern AF sustains higher diversity and demographic stability than in the southern AF. However, a pre-Pleistocene divergence associated with their abutting range limits in a region of past tectonic activity also suggests a role for rivers or geotectonic barriers. Little or no gene flow between these species suggests the development of reproductive barriers or competitive exclusion. Our results suggests that limited marker sampling in recent AF studies may compromise estimates of divergence times and historical demography, and we discuss the effects of such sampling on this and other studies.
大西洋森林（AF）拥有世界上最多样化的脊椎动物区系之一，包括 199 种特有鸟类。了解这种多样性背后的进化过程已成为许多最近的、主要是单一基因座的系统地理学研究的焦点。这些研究表明，森林避难所的隔离可能是促进多样化的主要机制，尽管也有河流和大地构造屏障的作用的支持，这两种假设可以通过多基因座数据得到最好的检验。在这里，我们结合了两种近缘蚁鸟（Myrmeciza loricata 和 M. squamosa）的多基因座数据（一个 mtDNA 标记和八个匿名核基因座）和近似贝叶斯计算，以确定避难所隔离是否解释了当前遗传变异的模式及其作为独立进化单位的地位。种群结构模式、种内分歧水平的差异以及历史人口动态的合并估计符合最近提出的避难所隔离模型的预测，即北部 AF 的气候稳定性比南部 AF 维持更高的多样性和人口动态稳定性。然而，与它们在过去构造活动区域相接的范围限制相关的上新世前分歧也表明了河流或大地构造屏障的作用。这些物种之间很少或没有基因流表明生殖障碍或竞争排斥的发展。我们的结果表明，最近的 AF 研究中有限的标记采样可能会影响分歧时间和历史人口动态的估计，我们讨论了这种采样对这和其他研究的影响。
