Characterization of B/C recombinants of near full-length HIV type 1 from northeastern India with mosaics identical to ARE195FL but with a different ancestral origin.

We have characterized near full-length genomes of three B/C recombinants of HIV-1 from the northeastern state of India. The recombinant viruses showed a backbone of subtype C virus with a single insertion of the subtype B genome in the envelope region. While all of them were distinct from B/C recombinants CRF_07 and CRF_08 circulating in China and CRF_04BR137 circulating in Brazil, two of them presented with break-points identical to the Argentinean B/C recombinant ARE195FL. However, neighbor-joining analysis followed by phylogenetic clustering showed that gp120 belonging to subtype B of all the recombinants clustered with Thai B sequences, while subtype C gag clustered with an Indian subtype C sequence, suggesting a unique ancestral origin of these recombinants.