Spellman Garth M, Klicka John
Marjorie Barrick Museum of Natural History, and School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland PKWY, Las Vegas, NV 89154, USA.
Mol Ecol. 2007 Apr;16(8):1729-40. doi: 10.1111/j.1365-294X.2007.03237.x.
Pine and oak woodlands are common North American floral communities with distinct regional species composition. The white-breasted nuthatch (Aves: Sitta carolinensis) is a common resident bird of North American pine and oak woodlands, and is distributed continentally across the highly disjunct distribution of these woodlands. We propose three historical hypotheses to explain the evolution of the white-breasted nuthatch in its principal habitat. (i) The species evolved in situ in the regional pine-oak communities and the isolation of populations in these regions is captured in cryptic genetic variation. (ii) Migration of individuals between regions is frequent enough to maintain the widespread distributions and prevent regional divergence. (iii) The species have recently expanded to occupy their current distributions and an insufficient amount of time has passed for divergence to occur. Phylogenetic analysis of mitochondrial DNA (ND2 gene) variation (N = 216) in the white-breasted nuthatch reveals four reciprocally monophyletic clades concordant with the distribution of the regional North American pine and oak woodlands, and supports hypothesis 1 of in situ evolution of populations in the regional pine and oak communities. Within-clade population structure and demographic history are also discussed.
松树和橡树林地是北美常见的植物群落，具有独特的区域物种组成。白胸坚果雀（鸟类：卡罗来纳坚果雀）是北美松树和橡树林地常见的留鸟，分布于这些林地高度分散的整个大陆范围。我们提出了三个历史假说，以解释白胸坚果雀在其主要栖息地的进化。（i）该物种在区域松树 - 橡树林群落中原地进化，这些区域种群的隔离在隐秘的遗传变异中得以体现。（ii）个体在区域间的迁移足够频繁，以维持广泛的分布并防止区域分化。（iii）该物种最近才扩张到占据其当前分布区域，且时间不足以发生分化。对白胸坚果雀线粒体DNA（ND2基因）变异（N = 216）的系统发育分析揭示了四个相互单系的分支，与北美区域松树和橡树林地的分布一致，并支持区域松树和橡树林群落中种群原地进化的假说1。还讨论了分支内的种群结构和种群历史。
