%0 Journal Article %T Characterization of HIV-1 gag and nef in Cameroon: further evidence of extreme diversity at the origin of the HIV-1 group M epidemic %A Tongo Marcel %A Martin Darren P %A Zembe Lycias %A Mpoudi-Ngole Eitel %J Virology Journal %D 2013 %I BioMed Central %R 10.1186/1743-422x-10-29 %X Background Cameroon, in west central Africa, has an extraordinary degree of HIV diversity, presenting a major challenge for the development of an effective HIV vaccine. Given the continuing need to closely monitor the emergence of new HIV variants in the country, we analyzed HIV-1 genetic diversity in 59 plasma samples from HIV-infected Cameroonian blood donors. Full length HIV gag and nef sequences were generated and phylogenetic analyses were performed. Findings All gag and nef sequences clustered within HIV-1M. Circulating recombinant form CRF02_AG predominated, accounting for 50% of the studied infections, followed by clade G (11%), clade D and CRF37_cpx (4% each), and clades A, F, CRF01_AE and CRF36_cpx (2% each). In addition, 22% of the studied viruses apparently had nef and gag genes from viruses belonging to different clades, with the majority (8/10) having either a nef or gag gene derived from CRF02_AG. Interestingly, five gag sequences (10%) and three (5%) nef sequences were neither obviously recombinant nor easily classifiable into any of the known HIV-1M clades. Conclusion This suggests the widespread existence of highly divergent HIV lineages in Cameroon. While the genetic complexity of the Cameroonian HIV-1 epidemic has potentially serious implications for the design of biomedical interventions, detailed analyses of divergent Cameroonian HIV-1M lineages could be crucial for dissecting the earliest evolutionary steps in the emergence of HIV-1M. %K HIV-1 diversity %K West central Africa %K RDP3 %K Maximum likelihood %K PHYML %U http://www.virologyj.com/content/10/1/29