School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, University of California-Davis, Davis, CA 95616, USA.
J Med Entomol. 2012 Mar;49(2):299-306. doi: 10.1603/me11108.
Resolution of systematic relationships among members of the Culex pipiens (L.) complex has important implications for public health as well as for studies on the evolution of sibling species. Currently held views contend that in California considerable genetic introgression occurs between Cx. pipiens and Cx. quinquefasciatus Say, and as such, these taxa behave as if they are a single species. Development of high throughput SNP genotyping tools for the analysis of Cx. pipiens complex population structure is therefore desirable. As a first step toward this goal, we sequenced 12 gene fragments from specimens collected in Marin and Fresno counties. On average, we found a higher single nucleotide polymorphism (SNP) density than any other mosquito species reported thus far. Coding regions contained significantly higher GC content (median 54.7%) than noncoding regions (42.4%; Wilcoxon rank sum test, P = 5.29 x 10(-5)). Differences in SNP allele frequencies observed between mosquitoes from Marin and Fresno counties indicated significant genetic divergence and suggest that SNP markers will be useful for future detailed population genetic studies of this group. The high density of SNPs highlights the difficulty in identifying species within the complex and may be associated with the large degree of phenotypic variation observed in this group of mosquitoes.
解析库蚊复合体成员之间的系统发育关系对于公共卫生以及研究姐妹种的进化具有重要意义。目前的观点认为，在加利福尼亚，库蚊和埃及伊蚊之间存在大量的遗传渗入，因此，这些分类群的行为就像是一个单一的物种。开发高通量 SNP 基因分型工具来分析库蚊复合体的种群结构是非常必要的。作为实现这一目标的第一步，我们对在马林县和弗雷斯诺县采集的标本进行了 12 个基因片段的测序。平均而言，我们发现的单核苷酸多态性（SNP）密度高于迄今为止报道的任何其他蚊子物种。编码区的 GC 含量（中位数为 54.7%）明显高于非编码区（42.4%；Wilcoxon 秩和检验，P = 5.29 x 10(-5)）。马林县和弗雷斯诺县的蚊子之间 SNP 等位基因频率的差异表明存在显著的遗传分化，并表明 SNP 标记将有助于未来对该组蚊子进行详细的种群遗传研究。SNP 的高密度突出了在该复合体中识别物种的困难，这可能与该组蚊子表现出的大量表型变异有关。
