Fig. 2

Molecular analysis of HIV-1 transmission in 41 couples by pol gene. a Maximum-likelihood phylogenetic tree. The first digit of the sequence numbers differentiates between the partners: “1” indicates the donor, “2” indicates the recipient; the remaining three digits represent the couple’s ID. Bootstrap values are shown for the grouping of couple sequences for each event, based on 1000 bootstrap replicates. b Maximum-likelihood genetic distance. The color and site of bars correspond to couples diagramed on the left. For the non-clustered couples, only one sequence has the bar value and the other sequence is labeled with the partner’s ID. The dotted line represents the median pairwise distance of the linked pairs