Scientists have identified the oldest known human viral RNA – a strain of the common cold – preserved in medical samples dating back approximately 250 years. The discovery offers a unique window into the evolutionary history of rhinoviruses, a family of viruses responsible for a significant portion of human illness.
Retrieving genetic information from viruses presents a challenge, as RNA, the molecule carrying the genetic code of many viruses, degrades rapidly after death, typically within hours. Whereas, researchers have occasionally been able to recover RNA from exceptionally well-preserved samples, such as those found in animals frozen in ice.
In this case, the virus was identified through genetic analysis of samples taken from two women in London around 1770 and 1777, according to New Scientist. Details of the findings are available in a preprint published on Biorxiv.
Reconstructing the Viral Sequence
The samples originated from the anatomical collection of the University of Glasgow’s museum in the United Kingdom, amassed by Dr. William Hunter, who held the first chair of anatomy at the Royal Academy of London in 1768. The lung tissue, preserved in alcohol rather than formaldehyde, contained fragments of viral RNA ranging from 20 to 30 nucleotides in length. Researchers used these fragments to reconstruct the virus’s RNA sequence.
“To give you an idea, RNA molecules in living cells generally measure more than 1,000 nucleotides,” explained Erin Barnett of the Fred Hutchinson Cancer Center in Seattle, to New Scientist. She further clarified:
“Instead of working with long, intact strands, we reconstructed the sequence from many tiny fragments.”
Read more on Courrier international
