Nearly a quarter of the Northern Hemisphere is covered by permafrost.
As the climate warms, permafrost melts irreversibly, releasing organic matter that has been frozen for a million years, most of which breaks down into carbon dioxide and methane, although some fungi, bacteria or viruses may also be released.
In an article published on Nov. 10 on the preprint platform bioRxiv, a joint team of scientists from multiple countries has initially isolated 13 new viruses from seven different Siberian paleofrost samples.
They successfully resurrected one virus from a permafrost sample that is approximately 48,500 years old and three new viruses from a 27,000-year-old frozen mammoth dung sample and fur sample.
In addition, they isolated 2 new viruses from the frozen stomach contents of a Siberian wolf (Canis lupus) and named them Pacmanvirus lupus and Pandoravirus lupus.
By culturing these viruses with amoeba protozoa, the researchers found that they were still able to infect the cells of the protozoa and replicate.
The study shows that more research is needed to focus on viruses in the tundra that can infect eukaryotes.