Seven thousand years ago, a young man about 25 or 30 years old, died in what is today central Germany. Though it is not known why he died, powerful new genetic tools might have given us a clue: the fragmented DNA of a virus that infected his liver all those millennia ago. According to The Atlantic, what was discovered in his body is the oldest virus ever directly sequenced, opening up a new window onto what came before modern life. Scientists have been studying human DNA from thousands-year-old teeth and bones for years. More recently, DNA from ancient bacteria, such as leprosy and plague, in those same teeth and bones have allowed for the study of past epidemics. Many considered viruses the next logical step in the exploration process, but they have very small genomes and are not structured in a way that typically remains intact over long periods of time. Until this week, the oldest virus ever sequenced was only a hundred years old. But now, two separate research groups report finding hepatitis B in teeth several millennia old in Eurasia.
The old hepatitis B viruses were all very strange and looked less like modern-day human viruses than the hepatitis B that infect chimpanzees and gorillas in Africa today. The Atlantic writes that whatever version of hepatitis B infected western Europe thousands of years ago seems to have gone extinct in humans, but remains in African chimps and gorillas. But who infected who and how did it cross over?
“The papers are really interesting,” says Margaret Littlejohn, a virologist at the Doherty Institute who has studied the origins and evolution of the hepatitis B virus, to The Atlantic. “But we felt they’re giving us more questions than answers.”
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