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

Area of Science:

• Evolutionary virology
• Phylogenetics
• Retroviral origins

Background:

• Previous research proposed monkeys acquired immunodeficiency retroviruses through a host-switch from humans.
• This hypothesis relied on specific interpretations of sequence alignment data, including third position transitions and gapped regions.

Discussion:

• The study critically examines the methodology used to determine the ancestral host for immunodeficiency retroviruses.
• It argues that optimizing hosts on the viral phylogeny is an illogical approach, treating hosts as dependent on viruses.
• This method overlooks significant advancements in phylogenetic methodology designed for cospeciation and host-switching analyses.

Key Insights:

• The conclusion that monkeys acquired retroviral infections from humans is not robust under rigorous scrutiny.
• Alternative analyses, when allowing all data to inform relationships, suggest an unequivocal simian ancestry or equivocal results.
• The assumption of human-to-monkey host-switching is challenged by established phylogenetic methods.

Outlook:

• Future research should employ advanced phylogenetic methods to accurately reconstruct retroviral evolutionary history.
• A re-evaluation of retroviral origins using modern techniques is necessary to resolve ancestral host ambiguities.
• Understanding host-virus evolutionary dynamics requires considering cospeciation and host-switching with appropriate methodologies.