Figure 1

Maximum-likelihood trees of env and pol genes from 4403–4419 MTCT pair. Maternal breast milk virus env (A) and pol (B) sequences (blue stars = right breast; blue circles = left breast) were obtained from a sample collected at 4 weeks postpartum and infant virus env (A) and pol (B) sequences (orange squares) were derived from a plasma sample collected at 12 weeks of age. Groups of identical/near-identical sequences (defined as sequences with four or fewer nucleotide substitutions compared to consensus sequence) in maternal breast milk (vertical blue bar) or infant plasma (vertical orange bar) are indicated. Greater than 90% of the indicated near-identical sequences had fewer than four substitutions compared to consensus. Numerals at nodes indicate approximate bootstrap support values ≥ 70%. The scale bar represents 0.001 (0.1%) nucleotide substitutions per site.