ABSTARCT

Malaria vectors of the Anopheles gambiae complex are made up six species of mosquitoes that are stable and are highly efficient vectors. This group comprises of major and minor vect ors, some of which are responsible for transmission of the most deadly strain of malaria parasite, Plasmodium falciparum . The evolutionary history of this species group was inferred using publically available DNA sequence data. Th e retrieved sequences were aligned usi ng CLUSTAL W; evolutionary history was inferred using Maximum Likelihood, Neighbor-Joining, and Minim um Evolution methods. Ancestral sequences were also inferred using the FASTML Server-based program for computing ancestr al sequences. Based on morphology, ecology and behaviour,
Anopheles gambiae and Anopheles arabiensis (major vectors) were found to evolve from a common ancestor. All the members of this complex were all AT rich. A. gambiae and A. arabiensishad the highest AT composition, while A. merus was the least AT rich among the complex. Evolutionary divergence estimates show that these two major vectors are genetically similar. A. quadriannulatus (non vector) and A. melas (minor vector) were also found to evolve from the same ancestor. Overall, this st udy gives an understanding of the ancestral lineage of the A. gambiae complex, which will be essential for understandi ng the origins, evolution, classification and epidemiology of this important disease vector. This may have important implic ations for the control of malaria