Population Genetic Structure of Culex quinquefasciatus in Osogbo Metropolis, Nigeria inferred from Mitochondrial COI sequences

Abstract

Culex mosquito is a major vector of some deadly and debilitating diseases that include lymphatic filariasis and West Nile fever. Understanding the population genetics structure plays a crucial role in unravelling the epidemiological pattern of mosquito-borne disease and facilitating effective vector control measures. Hence, this study investigated the population genetic structure of Culex mosquitoes within selected urban areas in Osogbo, Osun State, Nigeria using the mitochondrial cytochrome c oxidase subunit I (mtCOI) DNA region. Mosquito samples were collected from twelve (12) sampling sites in different locations in Osogbo, Osun State and identified on the basis of morphological characteristics followed by mtCOI gene amplification and sequencing. Cx. quinquefasciatus were observed to be significantly distributed in sampling locations. The results of sequence alignment showed stable genetic structure and a shared inter-spatial haplotype owing to the significantly low haplotype diversity (Hd = 0.154; π = 0.112). The TCS network revealed that the dominant haplotype H1 shares a connection with haplotype H19. Tajima’s D values were negative for the sequence datasets with p > 0.05; implying genetic equilibrium of the COI sequences in all populations. Phylogenetic tree analysis showed shared COI sequences and are present in the same subclusters. Intra and interspecies were observed to have varying nucleotide and haplotype diversities. High percentage similarities of the COI region may be linked to human activities that have enhanced gene flow and conferred beneficial mutation attributes. Thus, continuation of this trend could be disadvantageous to the vector control mechanisms for Cx. quinquefasciatus in the selected population.