Túnez Juan I, Cappozzo Humberto L, Nardelli Maximiliano, Cassini Marcelo H
Grupo de Estudios en Ecología de Mamíferos, DCB, Universidad Nacional de Luján and CONICET, Rutas 5 y 7 (6700), Luján, Provincia de Buenos Aires, Argentina.
Genetica. 2010 Aug;138(8):831-41. doi: 10.1007/s10709-010-9466-8. Epub 2010 Jun 6.
The north-central Patagonian coast is the sea lions most abundant area in Argentina. As occurs along the entire Atlantic coast, the distribution of breeding colonies at this smaller geographical scale is also patchy, showing at least three areas with breeding activity. We study the genetic structure and historical population dynamics of the species in five colonies in this area, analysing a 508 base-pair segment of the D-loop control region. Otaria flavescens showed 10 haplotypes with 12 polymorphic sites. The genealogical relationship between haplotypes revealed a shallow pattern of phylogeographic structure. The analysis of molecular variance showed significant differences between colonies, however, pairwise comparisons only indicate significant differences between a pair of colonies belonging to different breeding areas. The pattern of haplotype differentiation and the mismatch distribution analysis suggest a possible bottleneck that would have occurred 64,000 years ago, followed by a demographic expansion of the three southernmost colonies. Thus, the historical population dynamics of O. flavescens in north-central Patagonia appears to be closely related with the dynamics of the Late Pleistocene glaciations.
巴塔哥尼亚中北部海岸是阿根廷海狮数量最多的地区。正如整个大西洋海岸的情况一样，在这个较小的地理尺度上，繁殖群体的分布也是不连续的，至少有三个区域有繁殖活动。我们研究了该地区五个群体中该物种的遗传结构和历史种群动态，分析了D-loop控制区的一段508个碱基对的片段。南美海狮显示出10种单倍型，有12个多态性位点。单倍型之间的系统发育关系揭示了一种浅层次的系统地理结构模式。分子方差分析显示群体之间存在显著差异，然而，成对比较仅表明属于不同繁殖区域的一对群体之间存在显著差异。单倍型分化模式和失配分布分析表明，可能在64000年前发生了瓶颈效应，随后最南端的三个群体出现了种群扩张。因此，巴塔哥尼亚中北部南美海狮的历史种群动态似乎与晚更新世冰川作用的动态密切相关。
