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Abstract：
Nucleotide sequences representing nine genes and five presumptive genetic loci were used to infer phylogenetic relationships among seven Baylisascaris species, including one species with no previously available molecular data. These genes were used to test the species status of B. procyonis and B. columnaris using a coalescent approach. Phylogenetic analysis based on combined analysis of sequence data strongly supported monophyly of the genus and separated the species into two main clades. Clade 1 included B. procyonis, B. columnaris, and B. devosi, species hosted by musteloid carnivores. Clade 2 included B. transfuga and B. schroederi from ursids, B. ailuri, a species from the red panda (a musteloid), and B. tasmaniensis from a marsupial. Within clade 2, geographic isolates of B. transfuga, B. schroederi (from giant panda), and B. ailuri formed a strongly supported clade. In certain analyses (e.g., some single genes), B. tasmaniensis was sister to all other Baylisascaris species rather than sister to the species from ursids and red panda. Using one combination of priors corresponding to moderate population size and shallow genetic divergence, the multispecies coalescent analysis of B. procyonis and B. columnaris yielded moderate support (posterior probability 0.91) for these taxa as separate species. However, other prior combinations yielded weak or no support for delimiting these taxa as separate species. Similarly, tree topologies constrained to represent reciprocal monophyly of B. columnaris and B. procyonis individuals (topologies consistent with separate species) were significantly worse in some cases, but not others, depending on the dataset analyzed. An expanded analysis of SNPs and other genetic markers that were previously suggested to distinguish between individuals of B. procyonis and B. columnaris was made by characterization of additional individual nematodes. The results suggest that many of these SNPs do not represent fixed differences between nematodes derived from raccoon and skunk hosts.
摘要：
代表9个基因和5个推定遗传基因座的核苷酸序列用于推断7个Baylisscaris物种之间的系统发育关系，包括一个以前没有分子数据的物种。这些基因用于使用合并方法测试B.procyonis和B.columnaris的物种状态。基于序列数据组合分析的系统发育分析强烈支持了该属的单系，并将该物种分为两个主要进化枝。进化枝1包括B.procyonis，B.哥伦布，B.Devosi,由芥末类食肉动物寄养的物种。进化枝2包括来自熊病的transfugaB.和schroederiB.B.ailuri,一种来自红熊猫（芥菜）的物种，和来自有袋动物的塔斯马尼芽孢杆菌。在进化枝2中，转基因芽孢杆菌的地理分离株，B.schroederi（来自大熊猫），和B.ailuri形成了一个强力支撑的进化枝。在某些分析中(例如，一些单一基因)，塔斯马尼芽孢杆菌是所有其他Baylisscaris物种的姐妹，而不是来自熊类和小熊猫的姐妹。使用一种对应于中等种群规模和浅层遗传差异的先验组合，B.procyonis和B.columnaris的多物种合并分析为这些分类单元作为单独的物种提供了中等支持（后验概率为0.91）。然而,其他先前的组合对将这些分类单元划分为单独的物种产生了微弱或没有支持。同样，在某些情况下，被约束为表示B.columnaris和B.procyonis个体的互惠单生的树拓扑（与不同物种一致的拓扑）明显更差，但不是其他人，取决于分析的数据集。通过表征其他线虫个体，对SNP和其他遗传标记进行了扩展分析。结果表明，这些SNP中的许多并不代表来自浣熊和臭鼬宿主的线虫之间的固定差异。
