Molecular Characterization of Anopheles gambiae s.l. from the Three Vegetation Zones in Rivers State, Nigeria

Understanding the genetic structure of mosquito populations is important for addressing important biological and public health issues such as evolution, spread of insecticide resistance alleles and epidemiology of vector-borne diseases. Anopheles gambiae s.l. is comprised of genetically distinct species that are morphologically indistinguishable. This study therefore aims to establish the sibling species and molecular characterization of Anopheles gambiae s.l. responsible for transmitting malaria parasites in the three ecological zones. Sample collection was carried out during the rainy season from May to December which coincides with the peak period of vector abundance. Adults of laboratory-reared, field-collected larvae of this test-mosquitoes were used for this study. To characterize the vectors, DNA was extracted from tissues of An. gambiae s.l. samples, amplified and sibling species identified by multiplex polymerase chain reaction (PCR). Restricted fragment length polymorphism (RFLP) aided to identify the M ( An. coluzzi) and S ( An. gambiae s.s.) forms. Neighbor-Joining method was used to infer the evolutionary history. An. gambiae s.s. (sibling species) is present in the entire Rivers state while An. gambiae s.s. (S-form) predominates the lowland forest vegetation and An. coluzzi predominates the mangrove and fresh water swamp vegetations. The sequenced samples from the three vegetations were closely related to An. gambiae with accession number KP165373.1. The study makes available baseline information on characterization and monitoring of species of malaria vectors in Rivers State, Nigeria. Keywords: Molecular characterization, Anopheles gambiae, vegetation, Rivers State. DOI: 10.7176/ALST/98-03 Publication date: June 30 th 2023