Phylogenetic tree of the PBMC average sequence patient samples for subtyping. Bootstrap resampling values of 90 to 100% and 70 to 90% are represented by ∗∗ and ∗, respectively. A 277-nt segment of the C2-C3 region was used to construct these trees by the neighbor-joining method. env genetic subtypes are indicated. GenBank accession numbers for the reference sequences are: SIVcpz, AF115393; group O isolate MVP5180, E16837; subtype C isolates 94UG114 (U88824), 84ZR085 (U88822), ELI (K03454), and NDK (A34828); subtype AE isolates TN235 (L03P55) and 90CF402 (U51188); subtype F isolates BZ163 (L22085) and FIN9363 (AF075703); subtype G isolates DRCBL (AF084936), HH8793 (AF061640), and SE6165 (AF061642); subtype A isolates Q2317 (AF004885), SE7253 (AF069670), 92UG037 (U51190), IBNG (L39106), and U455 (M62320); subtype H isolates VI557 (U09666) and VI991 (AF190127); subtype cpx isolates GR84 (AF119819) and GR11 (AF119820); subtype J isolates SE9173 (AF082395) and SE9280 (AF082394); subtype C isolates ETH2220 (U46016), 92BR025 (U52953), 21068 (AF067155), and 96BW05.02 (AF110967); and subtype B isolates WEAU1.60 (U21135), HX2BR (K03455), RF (M17451), JRFL (U63632), and KAL153 (AF193276).