Molecular Characterisation and Population Genetics of Anopheles gambiae s.l. Across Ecological Zones of Kano State, North West Nigeria

This study provides a molecular characterisation and population genetic analysis of Anopheles gambiae sensu lato across three ecological zones of Kano State, located in Nigeria's North West geopolitical zone. Understanding the species composition and genetic structure of malaria vector populations is fundamental for the rational design of vector control interventions, particularly in the context of emerging insecticide resistance. Using a cross-sectional sampling design, adult female mosquitoes were collected from 18 communities across the Sahel, Sudan savanna, and irrigated agriculture zones using human-landing catches and CDC light traps. Species identification was performed by PCR-based SINE200 and SINEASS molecular assays. Population genetic analysis was conducted using 12 microsatellite loci on 320 individuals. The study addressed the research gap of zone-specific molecular data for malaria vector populations in Kano State. Anopheles coluzzii dominated in irrigated zones (71% of collections), while An. gambiae s.s. dominated in Sudan savanna sites (68%). Significant genetic differentiation (FST = 0.089) was observed between irrigated and savanna populations, suggesting reduced gene flow across ecological zone boundaries. Effective population size estimates were largest in irrigated zone populations, consistent with year-round breeding habitat availability. The findings have direct implications for targeting insecticide resistance monitoring and gene-drive vector control strategies at zone-specific An. coluzzii and An. gambiae s.s. populations. Keywords: Anopheles gambiae, molecular characterisation, population genetics, Kano State, malaria vectors.