Cossíos Daniel, Lucherini Mauro, Ruiz-García Manuel, Angers Bernard
Département de Sciences Biologiques, Université de Montréal, Centre-Ville, Canada.
BMC Evol Biol. 2009 Mar 30;9:68. doi: 10.1186/1471-2148-9-68.
While numerous studies revealed the major role of environmental changes of the Quaternary on the evolution of biodiversity, research on the influence of that period on current South-American fauna is scarce and have usually focused on lowland regions. In this study, the genetic structure of the pampas cat (Leopardus colocolo), a widely distributed felid, was determined and linked to ancient climate fluctuations on the Andean region.
Using both mitochondrial sequences and nuclear microsatellites, we inferred the existence of at least four groups of populations in the central Andes, while other three localities, with little sample sizes (n = 3), presented differences in only one of these markers. The distribution of these groups is correlated to latitude, with a central area characterized by admixture of numerous mitochondrial clades. This suggests colonization from at least three glacial refuges and a contact zone between 20 degrees and 23 degrees S following a glaciation event. The similar coalescence times of the mitochondrial haplotypes indicated that the major clades split approximately one million years ago, likely during the Pre-Pastonian glacial period (0.80 - 1.30 MYA), followed by a demographic expansion in every clade during the Aftonian interglacial period (0.45 - 0.62 MYA). Interestingly, this structure roughly corresponds to the current recognised distribution of morphological subspecies.
The four groups of populations identified here must be considered different management units, and we propose the three localities showing differences in only mtDNA or ncDNA as provisional management units. The results revealed the influence of ancient climate fluctuations on the evolutionary history of this species. It is expected that the other species of land vertebrates with a smaller or similar mobility have been affected in the same manner by the glacial and interglacial periods in the central Andes.
虽然众多研究揭示了第四纪环境变化对生物多样性演化的主要作用，但关于该时期对当前南美洲动物群影响的研究却很稀少，且通常集中在低地地区。在本研究中，我们确定了广泛分布的猫科动物潘帕斯猫（Leopardus colocolo）的遗传结构，并将其与安第斯地区古代气候波动联系起来。
利用线粒体序列和核微卫星，我们推断安第斯中部至少存在四组种群，而其他三个样本量较小（n = 3）的地区仅在其中一种标记上存在差异。这些种群的分布与纬度相关，中部地区的特征是众多线粒体分支的混合。这表明至少有三个冰川避难所的种群在此定居，并且在一次冰川事件后，在南纬20度至23度之间存在一个接触带。线粒体单倍型相似的合并时间表明，主要分支大约在一百万年前分裂，可能是在早更新世冰川期（0.80 - 1.30百万年前），随后在阿夫顿间冰期（0.45 - 0.62百万年前）每个分支都出现了种群扩张。有趣的是，这种结构大致对应于目前公认的形态亚种分布。
这里确定的四组种群必须被视为不同的管理单元，我们建议仅在mtDNA或ncDNA上显示差异的三个地区作为临时管理单元。结果揭示了古代气候波动对该物种进化历史的影响。预计安第斯中部的冰川期和间冰期也以同样的方式影响了其他具有较小或相似活动能力的陆地脊椎动物物种。
