HIV-1 CRF 02 AG polymerase genes in southern Ghana are mosaics of different 02 AG strains and the protease gene cannot infer subtypes.

Abstract

Background. Little is known about the detailed phylogeny relationships of CRF 02-AG HIV-1 polymerase genes in Ghana. The use of the protease gene of HIV-1 for subtyping has shown conflicting results. Methods. The partial polymerase gene sequences of 25 HIV-1 strains obtained with Viroseq reagents were aligned with reference subtypes and alignments trimmed to a 300 bp protease, 661 bp and 1005 reverse transcriptase sequence alignments. Phylogenetic relationships of these alignments were determined with the Neighbour-Joining method using 1000 replicates and recombination patterns determined for the sequences with RIP 3.0 in the HIV sequence database. Results. Unlike the other alignments, the protease gene had nodes with bootstrap values < 100% for repeat control sequences. Majority of the CRF 02-AG sequences from Ghana were made up of fragments of several strains of CRF 02-AG/AG strains. The protease gene alone is not suitable for phylogenetic analysis. Conclusion. The polymerase genes of HIV-1 strains from Ghana are made up of recombinants of several CRF 02-AG strains from Ghana, Senegal and Cameroon, but the clinical implications are unknown. Using the HIV-1 protease gene for subtyping will not infer subtypes correctly.