An Evaluation of Population Differentiation in Culex tarsalis in Montana Using COI Sequences

Abstract

The Infectious Disease Ecology project at Carroll College has established protocols to successfully detect West Nile virus in Culex tarsalis, a species of mosquito that acts as a vector for this disease. The detection data combined with ecological factors have been used to produce a risk model capable of predicting where West Nile positive specimens will be detected annually. This specific project aimed to determine the relatedness of C. tarsalis from various regions across the state of Montana as this knowledge could aid in determining how West Nile virus infections may spread across the state. Cytochrome c oxidase I (COI) gene sequences were analyzed from specimens from eleven locations across the state. Analyses included population pairwise distances and FST calculations, an analysis of molecular variance, and a neighbor-joining phylogenetic analysis. The results of these analyses suggest the Montana populations of Culex tarsalis are not genetically differentiated from one another. This means either that the populations truly are panmictic or that the sequence used is not informative for this question. Due to the low sequence variation among individuals, it seems more likely that this sequence is not an informative one for this study.