Crosbie P R, Boyce W M, Rodwell T C
Department of Veterinary Pathology, Microbiology and Immunology, University of California, Davis 95616-8739, USA.
J Med Entomol. 1998 May;35(3):277-88. doi: 10.1093/jmedent/35.3.277.
The genus Dermacentor is represented by 12 species in the New World. We sequenced a 300-bp portion of the mitochondrial 16S ribosomal DNA gene for 28 individual ticks representing 9 of these species and analyzed their phylogenetic relationships. Maximum parsimony, distance (neighbor-joining), and maximum likelihood were all used to resolve tree topologies. Eleven specimens of Dermacentor hunteri Bishopp representing populations across the tick's entire geographic range showed negligible genetic variation, with only single base-pair differences between each of 5 haplotypes. We found high degrees of bootstrap support (66-86%) for monophyly of the genus, but variable support for monophyly of species within the genus. D. hunteri, D. occidentalis Marx, and D. variabilis (Say) each resolved as a monophyletic taxon (79-99% support). D. andersoni Stiles and D. parumapertus Neumann formed a paraphyletic clade (99% support). D. albipictus Packard showed substantial intraspecific variation and warrants further investigation. D. imitans Warburton was distinct from all other Dermacentor spp. on all trees.
革蜱属在新大陆有12个物种。我们对代表其中9个物种的28只蜱虫的线粒体16S核糖体DNA基因的300个碱基对部分进行了测序，并分析了它们的系统发育关系。最大简约法、距离法（邻接法）和最大似然法都被用于解析树形拓扑结构。代表整个地理分布范围的11只亨特氏革蜱标本显示出可忽略不计的遗传变异，5个单倍型之间每个仅存在单个碱基对差异。我们发现该属单系性有高度的自展支持（66 - 86%），但该属内物种单系性的支持度有所不同。亨特氏革蜱、西方革蜱和变异革蜱各自解析为一个单系分类单元（支持度为79 - 99%）。安德逊革蜱和微小革蜱形成一个并系分支（支持度为99%）。白纹革蜱显示出显著的种内变异，值得进一步研究。仿革蜱在所有树形图上都与所有其他革蜱属物种不同。
