The New York Times reports:

Scientists have discovered a virus that is a tiny bit human, carrying a gene it stole from our ancestors about 100,000 years ago. And this virus may be using our own gene to infect us.

Previous studies have demonstrated that viruses can pick up genes from their hosts. But the new discovery, reported Thursday in the journal Science, may be the first known instance of a virus with a human gene acquired in recent evolutionary history.

“This one hits closer to home,” said Nels Elde, an evolutionary biologist at the University of Utah who was not involved in the research.

The way that viruses replicate makes them particularly good at thieving DNA.

They infect a cell, then co-opt its machinery by injecting their own genes. The infected cell is forced to make copies of the viral genes, along with proteins that package them into new viruses. The new viruses explode from the infected cell, which dies.

Sometimes this process goes awry, and a stretch of the host’s DNA gets bundled into the new viral genes. This molecular error can pose a threat to human health.

Viruses that infect bacteria, for example, can latch onto genes that the bacteria were using to resist antibiotics. These genes don’t do the viruses any direct good, but they can pass the DNA to other bacteria they infect. That’s one way that antibiotic resistance spreads.

Now scientists have discovered a virus that has picked up a gene from humans. The gene wasn’t hidden away: Cedric Feschotte, a biologist at Cornell University, and his colleagues found it as they scanned databases of viral genes. [Continue reading…]