Giant Virus Rises from the Past
The media are shocked that a virus resurrected from 30,000-year-old permafrost can still actively invade amoebas.
Authors of a paper in PNAS were exploring Siberian permafrost when they isolated a large “pandoravirus,” a type of unusually-large virus that attacks microbes like amoebas. The viruses look like amphorae (oblong jugs) with an orderly, honeycombed gate (capsid) at one end. Based on radiocarbon tests, the scientists claim the permafrost, excavated from 30 feet down, lay undisturbed for over 30,000 years (actually 34,000 to 37,000 years, they say in the paper). When they injected amoebas into the permafrost as “bait,” Nature says, they watched some of the amoebas die. Inspecting them, they found the pandoraviruses inside. Nature’s article quotes the surprise of one of the researchers, Jean-Michel Claverie:
We thought it was a property of viruses that they pack DNA extremely tightly into the smallest particle possible, but this guy is 150 times less compacted than any bacteriophage [viruses that infect bacteria]. We don’t understand anything anymore!”
The researchers worried that human pathogenic viruses might also lie dormant in permafrost and become active due to global warming. This sent the popular media, like National Geographic and the BBC News, into semi-panic mode, but Nature quoted virologist Curtis Suttle who says there’s no cause for alarm:
Claverie and Abergel are concerned that rising global temperatures, along with mining and drilling operations in the Arctic, could thaw out many more ancient viruses that are still infectious and that could conceivably pose a threat to human health.
But Suttle points out that people already inhale thousands of viruses every day, and swallow billions whenever they swim in the sea. The idea that melting ice would release harmful viruses, and that those viruses would circulate extensively enough to affect human health, “stretches scientific rationality to the breaking point”, he says. “I would be much more concerned about the hundreds of millions of people who will be displaced by rising sea levels.”
However one feels about the threat, the discovery points to unexpected diversity in large viruses. Some of them are so large, they blur the distinction between a virus and a bacterium, except that these giant viruses, like smaller ones, need a host to replicate. Science Magazine describes what is known about them:
Unlike most viruses, giant viruses are big enough to be seen with a light microscope. Indeed, the first one discovered was initially thought to be a bacterium, with comparable amounts of DNA. Since then, about 10 more have been found, including ones with more DNA than some bacteria, most infecting amoebas only. This new virus, called Pithovirus sibericum, has some characteristics of other giant viruses, but represents a third group of these unusual life forms. It’s the biggest to date, but has about half the DNA of others, researchers report online today in the Proceedings of the National Academy of Sciences. The soil studied was taken from 30 meters below the surface, and the researchers have samples dating back millions of years that they plan to test as well.
They referenced a 1999 paper that claimed to find a virus in glacial ice said to be 140,000 years old (Castello JD, et al.  Detection of tomato mosaic tobamovirus RNA in ancient glacial ice. Polar Biol 22(3):207-212).
To a French virologist, these findings show that viruses have a role to play in the ecology. “It is clear that giant viruses cannot be seen as stand-alone freaks of nature,” Christelle Desnues says. “They constitute an integral part of the virospherewith implications in diversity, evolution and even human health.” As for evolution, the PNAS paper cautions, “The hunt for these viruses is only beginning and speculations about their evolutionary origin should be postponed before many more are found.”
Radiocarbon vanishes after a few tens of thousands of years to levels too hard to date. Biblical creationists believe that the Flood year dramatically changed the radiocarbon profile in the atmosphere, rendering pre-Flood dates unreliable. It will be interesting to see if they find radiocarbon in the samples they claim are millions of years old. That would essentially falsify the moyboy dates. Or will they just refuse to look for radiocarbon, because they already “know” there “can’t” be any left? We say, test it!
There are so many viruses in the world, and they are so prevalent in every environment, the discovery should not be seen as that unusual. Undoubtedly there are many, many more viruses that have not yet been characterized. What’s important is the claim that these viruses are over 30,000 years old, and they might still be intact in permafrost claimed to be millions of years old. That’s the claim that should be “stretching scientific rationality to the breaking point.” Scientists should take to heart Claverie’s admission: “We don’t understand anything anymore!” Given that, “speculations about their evolutionary origin should be postponed” indefinitely, for, say, 30,000 years, or maybe millions.