PIP: Laboratory scientists used anchored polymerase chain reaction (PCR) and DNA sequencing to compare HIV-1 isolates from countries in Africa (Ivory Coast, Gabon, Zaire, Kenya, and others), Europe (Belgium and other countries), and the US. The US isolates had the most homogenous PCR profile followed by the European pattern. There was considerable PCR primer mispairing for the African isolates, especially those from Kenya, indicating that the range of HIV-1 variation could have been rather extensive. This virus diversity could greatly affect therapy or intervention in sites in Africa with such a complex mix of variants. Nevertheless, the genetic information of these diverse isolates could bring about research leading to an anti-HIV-1 vaccine. For example, the expanded DNA sequence data base could record phylogenetic relationships, thereby, helping researchers choose prototypic variants for vaccine development. More information would allow researchers to generate new PCR primers for better discrimination of variants. They could apply PCR typing to huge sample sizes to adequately document HIV-1 variation in Africa. It could also prove invaluable as a means to determine incidence and prevalence of local variants during vaccine field trials. It can also discern the limiting criteria for HIV-1 genetic variation.