Island Biogeography Reveals the Deep History of SIV

TLDR

Bioko Island’s geological age provides a calibration point for dating SIV, and its viruses span the full SIV diversity, each clade most closely related to mainland hosts of the same genus. Phylogeographic analysis shows SIV is at least 32,000 years old, and calibration and sequence‑saturation analyses suggest it may be much older.

Abstract

Simian immunodeficiency virus (SIV) lineages have been identified that are endemic to Bioko Island. The time the island formed offers a geological time scale calibration point for dating the most recent common ancestor of SIV. The Bioko viruses cover the whole range of SIV genetic diversity, and each Bioko SIV clade is most closely related to viruses circulating in hosts of the same genus on the African mainland rather than to SIVs of other Bioko species. Our phylogeographic approach establishes that SIV is ancient and at least 32,000 years old. Our conservative calibration point and analyses of gene sequence saturation and dating bias suggest it may be much older.