Molecular systematics of the Canidae

Despite numerous systematic studies, the relationships among many species within the dog family, Canidae, remain unresolved. Two problems of broad evolutionary significance are the origins of the taxonomically rich canid fauna of South America and the development in three species of the trenchant heel, a unique meat-cutting blade on the lower first molar. The first problem is of interest because the fossil record provides little evidence for the origins of divergent South American species such as the maned wolf and the bush dog. The second issue is problematic because the trenchant heel, although complex in form, may have evolved independently to assist in the processing of meat. We attempted to resolve these two issues and five other specific taxonomic controversies by phylogenetic analysis of 2,001 base pairs of mitochondrial DNA (mtDNA) sequence data from 23 canid species. The mtDNA tree topology, coupled with data from the fossil record, and estimates of rates of DNA sequence diverg...

尽管已有大量系统性研究，但犬科(Canidae)内诸多物种间的演化关系仍未明确。两大具有广泛演化意义的难题分别为：南美物种丰富的犬科动物区系的起源，以及三个物种演化出的锋利切割踵（trenchant heel）——一种位于下第一臼齿上的独特食肉切割刃结构。第一个难题备受关注，因为化石记录几乎无法为鬃狼、薮犬等特化南美犬科物种的起源提供佐证。第二个议题则存在争议：尽管该结构形态复杂，但它可能独立演化而来以辅助肉食加工处理。本研究通过对23个犬科物种的2001个碱基对线粒体DNA(mtDNA)序列数据开展系统发育分析，试图解决上述两大难题以及另外五个具体的分类学争议。基于线粒体DNA的系统发育树拓扑结构、结合化石记录数据以及DNA序列分化速率的估算……