Human Immunodeficiency Virus (HIV) is believed to have arisen in humans as a result of multiple independent cross-species exposures to Simian Immunodeficiency Viruses. Here the serial passaging of SIV in humanized mice across several generations recapitulates the genetic changes that make have facilitated such cross-species transmissions. Viral adaptation to the hu-mice was determined via qRT-PCR analysis of plasma viral loads and observation of CD4+ T-cell depletion. SIVs at various stages of adaptation from different generations were analyzed through Next Generation Sequencing (NGS). Many non-synonymous mutations were observed across each passage that may be responsible for improved cross-species transmission and adaptation
