Assessing Phylogeographic Patterns and Genetic Diversity in Culex quinquefasciatus (Diptera: Culicidae) via mtDNA Sequences from Public Databases.

Abstract

To identify the worldwide genetic structure, gene flow, and diversity of Culex quinquefasciatus, we conducted phylogeographic and population genetics analyses utilizing publicly available mtDNA sequences. Therefore, the aim of this study was to investigate the genetic structure and diversity of natural populations of C. quinquefasciatus worldwide, using available genetic data reflecting its natural distribution. Our study focused on the cytochrome c oxidase subunit I (COI) gene, mirroring the species' distribution pattern. We examined COI gene sequences from C. quinquefasciatus populations across Asia (n = 1,698), America (n = 334), Africa (n = 30), Oceania (n = 21), and Europe (n = 1), identifying 69 haplotypes. Genetic links were observed between Asian populations and those from other continents. Global genetic diversity was 0.531, varying from 0.095 in Oceania to 0.648 in South America. Neutrality tests indicated demographic expansions at the continental level in the Americas, North America, and Asia, as well as in some countries within these regions. In contrast, at both global and continental levels (South America, Oceania, and Africa), and in most countries within these continents, neutral populations were observed. AMOVA revealed genetic structuring among and within countries, with no genetic isolation observed (R ² = 0.03144; p > 0.05). Despite lower genetic diversity, Asian populations facilitated gene flow with other continents, suggesting a possible native origin of the species in Asia. The dispersal of this mosquito to new regions, coupled with its ability to transmit various arboviruses, underscores its significance as a potential public health threat.