infections of humans by lentiviruses of primate origin. A careful analysis of the high degree of relatedness between chimpanzees and humans was a major focus in Hanh’s laboratory. Knowing that chimpanzees and humans share more than 98% sequence identity across their genomes, Hanh sought to uncover what exactly varies in the interactions between virus and host that cause differences in viral pathogenicity. Hahn made advances in the understanding the origin of HIV-1, SIVcpz, and natural SIVcpz reservoirs. Study on Origin of HIV-1 The theorization that chimpanzees may be source of HIV-1 began when a chimpanzee was found to have a lentivirus (SIVcpzGAB1) that was closely related to HIV-1. The genome of SIVcpzGAB1 had an accessory gene that was so far unique to HIV-1 as well as many of the same reading frames. However, experiments carried out on more chimpanzees continuously resulted in apparently contradictory results as to whether chimpanzees were the original source of the SIVcpz. One experiment performed on fifty chimpanzees resulted in only two possessing HIV-1 cross-reactive antibodies, which showed a much lower SIVcpz infection rate in contrast to other naturally occurring SIV infections. This finding indicated that there was a third unknown source that both humans and chimpanzees could have acquired the virus from. Another study reported that a chimpanzee named Noah had a virus called SIVcpzANT that clustered with SIVcpzGAB1 (and HIV-1 strains) in phylogenetic trees but was twice as distant from SIVcpzGAB1 and HIV-1 strains as they were from each other. This resulted in more support for a third unknown source being the true SIVcpz reservoir. Hahn was able to prove the original theory through analyzation of the SIVcpz phylogeny in relation to the subspecies origin of the infected chimpanzee host. Her studies showed that the chimpanzees that had viruses similar to HIV-1 and to one another belonged to the same group; P.t. troglodytes. On the other hand, Noah, the chimpanzee with the virus that was extremely distant, was a P.t. schweinfurthii. This proved that the origin of a subspecies' chimpanzee host was what was responsible for two different phylogenetic lineages of SIVcpz strains. Hahn's careful phylogenetic analysis also supported that the source of HIV-1 was the chimpanzees that were members of P.t. troglodytes. Honors and awards 1999, Recipient, Birmingham Business Journal Top Birmingham Women 2001, Recipient, The Max Cooper Award for Research Excellence 2002, one of "The 50 Most Important Women in Science", Discover