An ancient virus has been found among the seeds stored in a 30,000-year-old squirrel nest. The virus is the latest of four “giant” viruses discovered so far in this one sample. It’s termed “giant” because it can be seen under a conventional microscope and has a large number of genes.
The find began when Jean-Michel Claverie, a professor of medical genomics and bioinformatics at a French university, read about a plant being revived from a seed after being buried for 30,000 years under Siberian permafrost. He was intrigued because the sample the seed came from came into contact with an ancient squirrel nest. Since squirrels are known for hoarding nuts and seeds, there was curiosity about what else might have been stored up. E-mails were exchanged and collaboration began.
When the samples were acquired by Claverie and his team, proper precautions were taken to ensure safety. “We’re not stupid enough to revive a virus that may pose a threat to human health,” Claverie stated bluntly.
What happened is best described as “microbial fishing.” Amoebas were used to bait out viruses within the sample. Amoebas were grown, mixed with permafrost samples in a petri dish, and monitored. For the most part, nothing happened. Occasionally, the amoebas would die and their samples were isolated and investigated. From this method, the virus was identified and named Mollivirus sibericum. The name is a mixture of the French word “moli,” meaning soft or flexible, and Siberia, where the samples were taken.
The fact that such a low concentration of the Moli virus was able to infect an amoeba was concerning to the scientists. However, more work needs to be done to determine if there is any credible risk from the mining excavations being undertaken in Siberia that have seen millions of tons of permafrost pulled up. There is potential to get a better understanding of the metabolic pathways and biochemical processes of the virus and how they have been carried down to the viruses of the modern world.
Sources for Today’s Article:
Christensen, J., “Ancient squirrel’s nest leads to discovery of giant virus,” CNN web site, last updated September 11, 2015; http://www.cnn.com/2015/09/11/health/ancient-squirrel-leads-to-giant-virus-discovery/index.html.
Legendre, M., et al., “Thirty-thousand-year-old Distant Relative of Giant Icosahedral DNA Viruses with a Pandoravirus Morphology,” Proceedings of the National Academy of Sciences 2014; 11: 4274–279, doi:10.1073/pnas.1320670111.
Legendre, M., et al., “In-depth Study of Mollivirus Sibericum, a New 30,000-y-old Giant Virus Infecting Acanthamoeba,” Proceedings of the National Academy of Sciences 2015, doi:10.1073/pnas.1510795112.