700-yo virus from ancient caribou poop revived, infects living plant

700-yo virus from ancient caribou poop revived, infects living plant
Scientists have successfully revived a 700-year-old virus that was frozen within ancient caribou feces, using it to infect a modern-day plant. The development raises the possibility that global warming could resurrect other infectious viruses.

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Scientific knowledge of ancient viruses is limited due to poor preservation and low concentrations, but genetic engineering is helping scientists replicate ancient viruses, and study how they interact with contemporary plants.

By replicating an age-old virus from ancient Canadian caribou feces (aCFV), researchers with the Blood Systems Research Institute in San Francisco say they have learned that viruses can remain infectious for centuries, motherboard.com reported.

We demonstrate that genetic material from ancient viruses associated with caribou fecal matter was cryogenically preserved for at least seven centuries, and that the cloned DNA genome of one of these viruses replicated and spread systematically in an extant plant,” Eric Delwart wrote in a study published in Proceedings of the National Academy of Sciences.

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However, the infection didn’t show up as an outward symptom of the disease, and to prove the plant was infected Delwart sequenced the genomes of newly-grown leaves on the plant. He was able to detect and isolate the viral DNA which had replicated inside the plant. There were no outward symptoms on the plant because tobacco wasn’t the virus’ original host. Whatever plant was the host, though, remains ancient history.

The virus was discovered in a Canadian ice patch, and because it had remained frozen for so long, the virus’ DNA was still in good shape and easy to separate as distinct from caribou DNA.

In another instance earlier this year, a French research couple found a 30,000-year-old virus frozen in the Siberian tundra. Scientists knew the virus’ host was an amoeba and tried seeing if the ancient virus could prove infectious. What they discovered when they tested their hypotheses was the amoebae were dying off, and the viruses were multiplying inside.

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"Sixty percent of its gene content doesn't resemble anything on Earth," Chantal Abergel at Aix-Marseille University told Nature about the virus.

Scientists have long known that viruses can survive for hundreds or thousands of years – after all, latent smallpox virus genes were discovered in 400-year-old mummies back in 1990. Still, an alarm is starting to sound about what happens when the Earth’s ice melts and the viruses preserved in ice start to revive. Will they prove harmful to human or animals?

There will be people where there were no people before, and those people are going to manipulate and disturb those [soil] layers that have not been disturbed for a million years,” said Claverie.

Delwart says studying the origins of certain viruses is good preparation to respond to ancient viruses if they do happen to become unfrozen and infectious.

"As climate change accelerates the melting of arctic ice, it is possible that ancient viral particles and the associated nucleic acids could be released into the environment," he wrote. "If such virions are infectious, their release could contribute to the diversity of circulating viruses."