Fig. 2.

Phylogenetic tree. Neighbor-joining phylogenetic trees were constructed from the sequences of clones obtained after PCR amplification of the SIV env V1-V2 region from day 7 or 14 PBMCs of low dose inoculated macaques (earliest SIV-positive sample). Bootstrap values from 500 replicates are indicated on each node if greater than 75%. Dots of the same shape and shade represent clones from the same animal. SIV Env V1-V2 sequences are depicted from all six low dose macaques as well as the SIV inoculum (A). Sequences from macaques 18984 and 18412 with the SIV inoculum are shown separately to demonstrate the higher diversity of transmitted virions in these two macaques (B and C respectively).