Phylogenetic analysis of the nef gene reveals a distinctive monophyletic clade in Korean HIV-1 cases

This study examines the genetic variation of the HIV-1 strains prevalent in South Korea. It analyzes the nef sequences derived from 46 HIV-1 positive individuals living in various geographic regions of Korea. Phylogenetic analysis revealed four subtypes of HIV-1: A (3 patients) B (41 patients) D (1 patient) and a type that could not be clearly classified as any known subtype (1 patient). About 35 of the 41 Korean subtype B isolates formed a distinct monophyletic clade that is not related to any of the international sequences from the Los Alamos Database or GenBank as of June 1997. Indeed the presence of unique conserved sequences was identified among the Korean isolates in this Korean subtype B group. The variations in the nucleotide sequences of a majority (32 of 35) of the subtype B isolates within the Korean clade were 3.9% to 15.5%. These results suggest that HIV-1 strains present in South Korea might have originated from a few sources or might be developing through a certain selective pressure.