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

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.