Microbiologists have found another giant virus in the permafrost of Siberia. These would be the second giant virus discovered in the area, following the discovery of Pithovirus sibericum in 2014. The newly discovered virus is the fourth known giant virus in the world.
The 30,000 years old giant virus Mollivirus sibericum were discovered by microbiologist after analyzing a sample of Siberian Permafrost.
In an in-depth study of the newly found giant virus featured in Proceedings of National Academy of Sciences of the United States of America (PNAS), microbiologists described the Mollivirus sibericum.
"Its [Mollivirus sibericum] approximately spherical virion (0.6-µm diameter) encloses a 651-kb GC-rich genome encoding 523 proteins of which 64% are ORFans; 16% have their closest homolog in Pandoraviruses and 10% in Acanthamoeba castellanii probably through horizontal gene transfer."
According to the MotherBoard, the first giant virus was discovered in a water sample from a cooling tower due to pneumonia outbreak that was caused by a bacteria and not the virus. It is named Mimivirus in 2003. The second giant virus is the Pandoravirus that was isolated in the water samples from Chile and Australia in 2013. By 2014, microbiologist discovered the third giant virus in the Siberian Permafrost, the Pithovirus sibericum.
According to the researchers, these four types of giant virus exhibit different virion structures, sizes (0.6-1.5 µm), genome length (0.6-2.8 Mb), and replication cycles. Their origin and mode of evolution are the subject of conflicting hypotheses. The fact that two different viruses could be easily revived from prehistoric permafrost should be of concern in a context of global warming.
The researchers concluded the possible danger of reawakening of the giant viruses in the Siberian Permafrost, "we cannot rule out that distant viruses of ancient Siberian human (or animal) populations could reemerge as arctic permafrost layers melt and/or are disrupted by industrial activities."
