Phylogenetic Analysis and Diversity of1 Envelope V3 Sequences from Seroconverters of the two Ethiopian Cohorts: Akaki & Wonji
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Date
2001-06
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Addis Ababa University
Abstract
HIV-I is characterized by its genetic variability. Based on nucleotide sequence
relatedness. the HIV -I virus variants are grouped into three groups: M (major). 0 (outlier).
and N (non-M or non-OJ. Group M viruses are further divided into 9 genetic subtypes or
clades (A-D. F-H. J. & K). The Ethiopian HIV-l/AIDS epidemic is reported to be
dominated by HIV-I subtype C. which recently is reported to have a genetic subcluster
designated as C'. In an effort to determine the diversity of gp120 V3 sequences and the
frequency of subtype C and C' viruses among HIV -I isolates from recently infected
individuals. 19 Ethiopian factory workers who seroconverted for HIV -I antibodies during
the year 1997-2000 were included in the study. HIV-I RNA was isolated from plasma
samples of study subjects. the RNA was reverse transcribed into cDNA and the envelope
gpl20 V3 region was amplified. Phylogenetic analysis of the env V3 sequences showed
all the 19 subjects to be infected by subtype C. II out of the 15 sequences were found to
be subtype C' and 4 SUbtype C. Based on this observation we speculate that subtype C'
viruses are spreading and might have a selective advantage for transmission. Amino acid
sequence comparison of the two groups of viruses showed significant amino acid sequence
differences. There was a 17% synonymous and 15% non synonymous distance among all
the seroconverter sequences and a 24% synonymous and 17% nonsynonymous distance
between the C and C' group of sequences. The synonymous distance among subtype
C'(9%) is much less compared to the distance among the SUbtype C sequences (16%).
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Biology