For more than 50 years, the RNA remained hidden in a lymph node that had been snipped out of a 38-year-old man in what is now the Democratic Republic of the Congo. That nub of tissue, the size of a nail on a pinky finger, had been sealed up in a protective block of paraffin.
Once freed from its wax casing, scientists at the University of Arizona were able to extract from the tissue a nearly complete genetic sequence of an HIV virus — the oldest nearly full-length genetic code for an HIV-1 virus recovered thus far, and one that supports the theory that the virus that causes AIDS began to transmit among people within the first decade or two of the 20th century.
“Generating a complete genome … from an archived tissue specimen is technically impressive,” [evolution and infectious disease professor Oliver] Pybus told STAT. “Although its discovery doesn’t substantially alter our current model of the early genetic history of the AIDS pandemic, it does improve our confidence in conclusions previously drawn from modern and partial HIV gene sequences.”