Sei Makiri, Porter Adam H
The Graduate Program in Organismic and Evolutionary Biology, Department of Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003-9297, USA.
Mol Ecol. 2007 Aug;16(16):3313-25. doi: 10.1111/j.1365-294X.2007.03384.x.
Species delimitation is a difficult problem that has implications across organismal biology, yet no single method has proved wholly satisfactory. We tested the utility of combining species-delimitation methods based on phylogeny and gene flow statistics using two parapatric members of the Coenonympha tullia group as an example: the endangered maritime ringlet butterfly (Coenonympha nipisiquit McDunnough) and the common inornate ringlet butterfly (Coenonympha inornata Edwards). We reconstructed the phylogeny of the nearctic C. tullia-group taxa from mitochondrial DNA (mtDNA) sequences (cytochrome oxidase I and mitochondrial control region) to explore the ancestry of the C. nipisiquit lineage within the group. We investigated the extent of gene flow between the two taxa with F-statistics using 587 nuclear amplified fragment length polymorphism markers, accounting for the effect of potential scoring 'collisions' where a marker may represent more than one DNA fragment. Combining species-delimitation methods was especially effective because it uncovered both historical and recent evolutionary patterns. Phylogenetic analysis of mtDNA revealed the early divergence of C. nipisiquit from other C. tullia-group taxa, including the morphologically similar C. inornata. F-statistics and gene-by-gene introgression profiles demonstrated clear isolation between the two taxa and revealed strong population structure within C. nipisiquit. C. nipisiquit is the first taxon in the nearctic C. tullia group showing strong evidence of genetic isolation. The methods we used are relatively inexpensive and can be widely used to delimit taxonomic boundaries near the species level, both generally and in particular for taxa that may be targets of conservation efforts.
物种界定是一个难题，对整个生物生物学都有影响，但没有一种单一方法被证明是完全令人满意的。我们以Coenonympha tullia组的两个邻域成员为例，测试了基于系统发育和基因流统计的物种界定方法相结合的效用：濒危的滨海环蛱蝶（Coenonympha nipisiquit McDunnough）和常见的无饰环蛱蝶（Coenonympha inornata Edwards）。我们从线粒体DNA（mtDNA）序列（细胞色素氧化酶I和线粒体控制区）重建了新北区C. tullia组分类群的系统发育，以探索该组内C. nipisiquit谱系的祖先。我们使用587个核扩增片段长度多态性标记，通过F统计量研究了两个分类群之间的基因流程度，考虑了潜在评分“冲突”的影响，即一个标记可能代表多个DNA片段。结合物种界定方法特别有效，因为它揭示了历史和近期的进化模式。mtDNA的系统发育分析表明，C. nipisiquit与其他C. tullia组分类群早期分化，包括形态相似的C. inornata。F统计量和逐个基因的基因渗入图谱表明两个分类群之间有明显的隔离，并揭示了C. nipisiquit内部强大的种群结构。C. nipisiquit是新北区C. tullia组中第一个显示出强烈遗传隔离证据的分类群。我们使用的方法相对便宜，可以广泛用于划定物种水平附近的分类边界，一般而言，特别是对于可能是保护努力目标的分类群。
