Evidence for a population expansion in the West Nile Virus vector Culex tarsalis
Autor(es): Venkatesan, Meera; Westbrook, Catherine J.; Hauer, M. Claire; Rasgon, Jason L.
Resumo: Population genetic structure of the West Nile Virus vector Culex tarsalis was investigated in 5 states in the western United States using 5 microsatellite loci and a fragment of the mitochondrial reduced form of nicotinamide adenine dinucleotide dehydrogenase 4 (ND4) gene. ND4 sequence analysis revealed a lack of isolation by distance, panmixia across all populations, an excess of rare haplotypes, and a star-like phylogeny. Microsatellites revealed moderate genetic differentiation and isolation by distance, with the largest genetic distance occurring between populations in southern California and New Mexico (F-ST = 0. 146). Clustering analysis and analysis of molecular variance on microsatellite data indicated the presence of 3 broad population clusters. Mismatch distributions and site-frequency spectra derived from mitochondrial ND4 sequences displayed pattern's characteristic of population expansion. Fu and Li's D* and F*, Fu's F-S, and Tajima's D statistics performed on ND4 sequences all revealed significant, negative deviations from mutation-drift equilibrium. Microsatellite-based multilocus heterozygosity tests showed evidence of range expansion in the majority of populations. Our results suggest that C. tarsalis underwent a range expansion across the western United States within the last 375,000-560,000 years, which may have been associated with Pleistocene glaciation events that occurred in the midwestern and western United States between 350,000 and 1 MYA.
Palavras-Chave: Cidex tarsalis; Genetic structure; Population expansion; West Nile virus
Imprenta: Molecular Biology and Evolution, v. 24, n. 5, p. 1208-1218, 2007
Identificador do objeto digital: 10.1093/molbev/msm040
Descritores: Aedes aegypti - DNA
Data de publicação: 2007
