Spellman Garth M, Klicka John
Department of Biological Sciences, University of Nevada, Las Vegas, NV 89154, USA.
Proc Biol Sci. 2006 Dec 22;273(1605):3057-63. doi: 10.1098/rspb.2006.3682.
In this paper, we use mitochondrial NADH dehydrogenase subunit 2 sequences to test Pleistocene refugial hypotheses for the pygmy nuthatch (Sitta pygmaea). Pygmy nuthatches are a common resident of long-needle pine forests in western North America and demonstrate a particular affinity with ponderosa pine (Pinus ponderosa). Palaeoecological and genetic data indicate that ponderosa pine was isolated in two Pleistocene refugia corresponding to areas in the southern Sierra Nevada in the west and southern Arizona and New Mexico in the east. We use coalescent simulations to test the hypothesis that pygmy nuthatches tracked the Pleistocene history of their preferred habitat and persisted in two refugia during the periods of glacial maxima. Coalescent simulation of population history does not support the hypothesis of two Pleistocene refugia for the pygmy nuthatch. Instead, our data are consistent with a single refuge model. Nucleotide diversity is greatest in the western populations of southern and coastal California. We suggest that the pygmy nuthatch expanded from a far western glacial refuge into its current distribution since the most recent glacial maximum.
在本文中，我们使用线粒体烟酰胺腺嘌呤二核苷酸脱氢酶亚基2序列来检验美洲姬啄木鸟（Sitta pygmaea）的更新世避难所假说。美洲姬啄木鸟是北美西部长叶松林中的常见留鸟，并且对黄松（Pinus ponderosa）表现出特别的偏好。古生态和遗传数据表明，黄松在更新世被隔离在两个避难所中，分别对应西部内华达山脉南部地区以及东部亚利桑那州南部和新墨西哥州。我们使用溯祖模拟来检验以下假说：美洲姬啄木鸟追踪其偏好栖息地的更新世历史，并在冰期最大值期间在两个避难所中存续。种群历史的溯祖模拟并不支持美洲姬啄木鸟存在两个更新世避难所的假说。相反，我们的数据与单一避难所模型一致。核苷酸多样性在加利福尼亚南部和沿海的西部种群中最高。我们认为，自最近一次冰期最大值以来，美洲姬啄木鸟从遥远的西部冰川避难所扩展到了其当前的分布范围。
