The AIDS Pandemic is New, but is HIV Not New?

Abstract

The determinations made by Mindell, Shultz and Ewald regarding the ancestral host for immunodeficiency retroviruses, and their conclusion that monkeys acquired their infections as a result of a host-switch from humans, do not withstand rigorous scrutiny. Their hypothesis requires the complete uniformativeness of third position transitions and of gapped regions in the alignment. When all of the data are permitted to corroborate or refute relationships, optimizing hosts on the viral phylogeny renders either equivocal statements or an unequivocal simian ancestry. However, merely optimizing hosts as characters on the viral phylogeny is illogical. Not only does this treat hosts as dependent on the viruses (instead of the reverse) but it ignores 15 years of methodological developments specifically designed to answer questions regarding cospeciation or host-switching. © 1997 The Willi Hennig Society.