Researchers have long wondered when exactly HIV made the leap into humans, and with a new discovery we are one step closer to an answer. Scientists from the University of Arizona have genetically sequenced a 53-year-old tissue sample that had been stored in paraffin in the Democratic Republic of Congo.
From this sample they were able to extract the oldest almost full-length genetic code of an HIV virus yet discovered. This sequence predates the first recorded outbreak in the United States by 15 years.
By looking at HIV genetic sequences researchers are able to estimate when HIV was first passed from primates into humans. They do this by comparing how genetically diverse the circulating virus is in different people at similar time points; more diversity means it has been in humans for longer, less diversity means the virus has been in humans for a shorter time.
This sequence suggests that the virus was first transmitted from primates to people earlier than the 1920s, as some researchers suggest. In fact, this event may have taken place as far back as the final years of the 1800s. Additional samples will need to be discovered if we are to have a firm answer of exactly how long HIV has been in humans, but this sample brings us a little closer to that answer.
Source: STAT news
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