EPIDEMIOLOGY: PDF OnlyPhylogenetic Analysis of thenefGene Reveals a Distinctive Monophyletic Clade in Korean HIV-1 CasesKang, Mi Ran*; Cho, Young-Keol†; Chun, Jongsik*; Kim, Young-Bong‡; Lee, Im-soon*; Lee, Hee Jung†; Kim, Seon Hee*; Kim, Yoo-Kyum†; Yoon, Keejung*; Yang, Jai-Myung‡; Kim, June Myung§; Shin, Yung-Oh∥; Kang, Chun∥; Lee, Joo Shil∥; Won Choi, Kang∥; Kim, Dae-Ghon¶; Fitch, Walter M.#; Kim, Sunyoung* Author Information *Institute for Molecular Biology and Genetics and Medical College, Seoul National University; †Department of Microbiology, University of Ulsan College of Medicine; ‡Department of Life Science, Sogang University; §Yonsei University College of Medicine; ∥National Institute of Health; and ¶Chonbuk National University Medical School, Korea; and #University of California, Irvine, California, U.S.A. Address correspondence and reprint requests to Sunyoung Kim, IMBG, Building 105, Kwan-Ak-Gu, Seoul 151-742, Korea. The first two authors contributed equally to the work reported in this paper. Manuscript received August 26, 1997; accepted September 15, 1997. Journal of Acquired Immune Deficiency Syndromes & Human Retrovirology: January 1, 1998 - Volume 17 - Issue 1 - p 58-68 Free Abstract To study the genetic variation of the HIV-1 strains prevalent in South Korea, we analyzed the nef sequences derived from 46 HIV-1-positive individuals living in various geographic regions in 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 to any known subtype (1 patient). Thirty-five 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) subtype B samples within the Korean clade were 1.9% to 8.8%, and amino acid sequences varied from 3.9% to 15.5%. These results suggest that HIV-1 strains currently present in South Korea might have originated from a few sources or might be developing through a certain selective pressure. This is the first report on the molecular nature of the HIV-1 infection present in South Korea. © Lippincott-Raven Publishers.