Drovetski Sergei V, Zink Robert M, Mode Nicolle A
CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Rua Padre Armando Quintas, Crasto 4485-661 Vairão, Portugal.
Mol Phylogenet Evol. 2009 Mar;50(3):437-45. doi: 10.1016/j.ympev.2008.12.002. Epub 2008 Dec 8.
DNA sequence data often appear to contradict low-level avian taxonomy, which is usually based on patterns of external phenotypic similarity. We examined such an apparent contradiction in the Nearctic rosy-finches. On the basis of several phenotypic characters the finches were divided into three species congeneric with three Asian species. When Nearctic taxa were analyzed in a principal components analysis, 66.9% of phenotypic variation was explained by differences between the Bering Sea and continental populations, sexual dimorphism and a latitudinal cline. Our phylogenetic analysis of mitochondrial ND2 sequences revealed four clades among six species of rosy-finches. Three clades corresponded to three Asian species. The fourth clade included all three Nearctic species. Their haplotypes were not reciprocally monophyletic and the combined genetic variability of all Nearctic taxa was lower than in two of their Asian congeners. A Z-specific intron (ACO1I9) and an autosomal coding locus (MC1R) provided little additional phylogenetic information, most likely because of the longer coalescence times relative to ND2. Phylogeographic analyses of ND2 data revealed significant gene flow among neighboring localities regardless of their taxonomic assignment. Our analyses showed that DNA and phenotypic data are not in conflict, but rather complement each other, and together help clarify species limits. Our data are consistent with a single species in North America, not three.
DNA序列数据往往似乎与基于外部表型相似模式的低级别鸟类分类法相矛盾。我们研究了新北界朱雀中这样一个明显的矛盾情况。根据几个表型特征，这些朱雀被分为三个物种，与三个亚洲物种同属。在主成分分析中对新北界分类群进行分析时，66.9%的表型变异可由白令海种群与大陆种群之间的差异、两性异形和纬度渐变来解释。我们对线粒体ND2序列的系统发育分析揭示了六种朱雀中的四个进化枝。三个进化枝对应于三个亚洲物种。第四个进化枝包括所有三个新北界物种。它们的单倍型并非相互单系的，并且所有新北界分类群的组合遗传变异性低于它们的两个亚洲同属物种。一个Z特异性内含子（ACO1I9）和一个常染色体编码位点（MC1R）几乎没有提供额外的系统发育信息，很可能是因为相对于ND2而言，它们的合并时间更长。对ND2数据的系统地理学分析表明，无论其分类归属如何，相邻地区之间都存在显著的基因流动。我们的分析表明，DNA数据和表型数据并不冲突，而是相互补充，共同有助于厘清物种界限。我们的数据与北美洲只有一个物种而非三个物种的情况一致。
