Evidence for a Population Expansion in the West Nile Virus Vector Culex tarsalis

Abstract

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.

Distribution and Phylogenetic Comparisons of a Novel Mosquito Flavivirus Sequence Present in Culex tarsalis Mosquitoes from Western Canada with Viruses Isolated in California and Colorado

“…tarsalis populations in North America. 24,25 This finding could explain why similar CLBOV genotypes have been identified in Manitoba and Colorado. Detailed genetic studies of CLBOVs from geographically isolated Cx.…”

Insight into the population structure of hardhead silverside,Atherinomorus stipes(Teleostei: Atherinidae), in Belize and the Florida Keys usingnd2

“…The Floridian populations exhibited a classic starburst pattern haplotype network (Figure 5) and had highly significant negative values of Tajima's D, Fu and Li's D*, and Fu and Li's F* (Table A2). These attributes suggest populations were evolving under nonrandom evolutionary processes, with the most plausible scenario being a recent demographic crash, such as a population bottleneck, followed by a rapid expansion in population size (Grant & Bowen, 1998; Avise, 2000; Depaulis, Mousset, & Veuille, 2003; Venkatesan, Westbrook, Hauer, & Rasgon, 2007; Tipton et al., 2011). …”

Phylogeography of Aedes aegypti (Yellow Fever Mosquito) in South Florida: mtDNA Evidence for Human-Aided Dispersal

“…aegypti 11,[24][25][26][27][28][29][30] and other mosquitoes 23,31,32 showed variability in the ND4 and ND5 sequences that yielded reliable gene genealogies suitable for inferring population structure and contributions of historical and current demographic processes. Both forward and reverse strands were sequenced using the ABI 3100 automated sequencer at the Keck Center, University of Illinois, Urbana-Champaign, IL.…”