Recuero Ernesto, Martínez-Solano Iñigo, Parra-Olea Gabriela, García-París Mario
Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal, 2. 28006 Madrid, Spain.
Mol Phylogenet Evol. 2006 May;39(2):293-304. doi: 10.1016/j.ympev.2005.10.011.
The Baja California populations of Pseudacris regilla, a widespread species in Western North America ranging from British Columbia to southern Baja California, are characterized by extensive geographic fragmentation. We performed phylogeographic and historical demographic analyses on 609 bp of the cytochrome b mitochondrial gene of 110 individuals representing 28 populations to determine the relative influences of current and historical processes in shaping the present distribution of genetic diversity on the Baja California Peninsula. Haplotypes from this area were nested in a clade with three well-differentiated groups. Two of these groups are from Baja California Sur and another is from California and Baja California. The estimated date for the split of these groups, between 0.9-1 Ma, fits with previously proposed hypotheses of vicariance due to different transpeninsular seaways, although successive population fragmentation and expansion due to climatic oscillations during Pleistocene glaciations cannot be discarded. Historical demographic analyses detected signs of past population expansions, especially in the southernmost group. With respect to populations north of this region, two older clades were identified, one with haplotypes mainly distributed in central California, and the other corresponding to the northern half of the species range, in what apparently is a recurrent pattern in the Pacific coast of North America. Based on the concordance between mt-DNA and available allozyme data indicating that these species have a long independent evolutionary history, we propose to consider the three major clades as distinct species: P. regilla, P. pacifica, and P. hypochondriaca.
北美西部广泛分布的细纹伪蝗蛙（Pseudacris regilla），其分布范围从英属哥伦比亚到下加利福尼亚半岛南部，下加利福尼亚半岛的种群具有广泛的地理隔离特征。我们对代表28个种群的110个个体的细胞色素b线粒体基因的609个碱基对进行了系统地理学和历史种群统计学分析，以确定当前和历史过程对塑造下加利福尼亚半岛遗传多样性当前分布的相对影响。该地区的单倍型嵌套在一个包含三个分化良好的类群的进化枝中。其中两个类群来自南下加利福尼亚，另一个来自加利福尼亚和下加利福尼亚。这些类群的分化估计时间在0.9 - 1百万年前，这与之前提出的由于不同的半岛海峡导致的地理隔离假说相符，尽管更新世冰川期气候振荡导致的连续种群碎片化和扩张也不能被排除。历史种群统计学分析检测到过去种群扩张的迹象，特别是在最南端的类群中。关于该地区以北的种群，鉴定出两个较古老的进化枝，一个进化枝的单倍型主要分布在加利福尼亚中部，另一个对应于该物种分布范围的北半部，这显然是北美太平洋沿岸的一种反复出现的模式。基于线粒体DNA与现有等位酶数据的一致性，表明这些物种具有长期独立的进化历史，我们建议将这三个主要进化枝视为不同的物种：细纹伪蝗蛙（P. regilla）、太平洋伪蝗蛙（P. pacifica）和肋下伪蝗蛙（P. hypochondriaca）。
