Virus World

Scientists at the University of Arizona were able to extract from the tissue a nearly complete genetic sequence of an HIV virus. For more than 50 years, the DNA 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.

 

The sample that was examined dates from 1966. The sequence extracted from it is older by a decade than the previous oldest full-length sequence. It provides a snapshot of what the virus looked like when it was circulating undetected in central Africa 15 years before a cluster of strange infections among gay men in the United States led to recognition of a new disease that was eventually called AIDS. 

 

Worobey, whose lab has repeatedly performed virologic archeology on old tissue and blood samples, said the paper has not yet been submitted to a scientific journal for publication. As such, it has not been through the peer review process where independent scientists kick its tires, so to speak. Genetic codes of viruses that infected people in earlier days of the AIDS epidemic can be used by scientists to try to date when the HIV virus moved from primates into people. By studying differences in the viral sequences, scientists estimate how long it has been since the known sequences could have diverged from a common source. It doesn’t tell them when the event happened, but it can suggest that it had to have been prior to a particular time, Worobey said, adding that the new data suggest the jump likely did not happen in the 1920s.

 

Findings were  pre-printed in the bioRxiv website:

https://www.biorxiv.org/content/10.1101/687863v1