Wheat Christopher W, Watt Ward B
Department of Biological Sciences, 371 Serra Mall, Stanford University, Stanford, CA 94305-5020, USA.
Mol Phylogenet Evol. 2008 Jun;47(3):893-902. doi: 10.1016/j.ympev.2008.03.013. Epub 2008 Mar 16.
We study the phylogenetic relationships among some North American Colias ("sulfur") butterflies, using mitochondrial gene sequences (ribosomal RNA, cytochrome oxidase I+II) totaling about 20% of the mitochondrial genome. We find that (1) the lowland species complex shows a branching order different from earlier views; (2) several montane and northern taxa may be more distinct than in earlier views; (3) one morphologically conservative Holarctic assemblage, C. hecla, is differentiated at the molecular-genetic level into at least three taxa which occupy distinct positions in the phylogeny and are sisters to diverse other taxa. These conclusions, constituting phylogenetic hypotheses, are supported by parsimony, maximum-likelihood, and Bayesian reconstruction algorithms. They are tested formally, by interior branch tests and paired-site tests, against alternative hypotheses derived from conventional species and subspecies naming combinations. In all cases our hypotheses are supported by these tests and the conventional alternatives are rejected. The "barcoding" subset of cytochrome oxidase I sequence identifies only some of the taxa supported by our full data set. Comparison of genetic divergence values among Colias taxa with those among related Pierid butterflies suggests that species radiations within Colias are comparatively younger. This emerging Colias phylogeny facilitates comparisons of genetic polymorphism and other adaptive mechanisms among taxa, thereby connecting micro- and macro-evolutionary processes.
我们利用线粒体基因序列（核糖体RNA、细胞色素氧化酶I+II）研究了一些北美云粉蝶属（“硫磺”）蝴蝶之间的系统发育关系，这些序列总计约占线粒体基因组的20%。我们发现：（1）低地物种复合体呈现出与早期观点不同的分支顺序；（2）几个山地和北方类群可能比早期观点所认为的更为独特；（3）一个形态保守的全北区类群，赫克拉云粉蝶，在分子遗传水平上分化为至少三个类群，它们在系统发育中占据不同位置，并且是其他不同类群的姐妹群。这些构成系统发育假说的结论得到了简约法、最大似然法和贝叶斯重建算法的支持。通过内部支序检验和配对位点检验，我们对这些假说进行了正式检验，以对抗源自传统物种和亚种命名组合的替代假说。在所有情况下，我们的假说都得到了这些检验的支持，而传统的替代假说则被拒绝。细胞色素氧化酶I序列的“条形码”子集仅识别出我们完整数据集所支持的部分类群。将云粉蝶属类群之间的遗传分歧值与相关粉蝶科蝴蝶之间的遗传分歧值进行比较，结果表明云粉蝶属内的物种辐射相对较新。这一新兴的云粉蝶属系统发育关系有助于比较类群之间的遗传多态性和其他适应机制，从而将微观和宏观进化过程联系起来。
