Imagine that 50,000 years ago, in a cave in Siberia, you died. Some day soon you may be brought back to life – sort of.
Using a fragment of a human finger bone found in that cave, scientists have sequenced the genome of an extinct group of humans known as the Denisovans – so called after the name of the cave at Denisova.
Along with the Neanderthals, the Denisovans are the closest extinct relatives of modern humans.
The cave at Denisova where remains of an extinct human species were found
A new technique has enabled people from the Max Planck Institute in Germany to sequence every position in the Denisovan genome 30 times over, a far more detailed scan, according to a paper published in the journal PLoS One.
Discoveries like this one are changing long-held theories about how humankind spread around the world. Until recently, it looked like human ancestors trekked out of Africa about 100,000 years ago in basically a single migration that led to modern humans. But what’s emerged from fossil findings in recent years is a picture of Homo sapiens and its near relatives flowing out of Africa again and again, with some populations vanishing and others surviving, often living side-by-side. Different strains separated, then met up again and interbred, then separated once more.
“We haven’t been a very exclusive species, with a very narrow origin,” Martin Jacobsson told Wired magazine. Interbreeding with other members of the human family tree “is not a unique event. It’s a more complex story than we thought before. We were evolving for a little while, then isolated, then mixed again. It’s not so simple that you can say, there’s only been one admixture.”
In terms of understanding our ancestry, it’s an exciting and fascinating accomplishment. But there are serious concerns that some researchers may try to use Denisovan DNA to clone these ancient humans – bringing to life an identical twin of the person who died back in that cave.
There’s already been a debate in the last several years over cloning Neanderthals. One of the main arguments in favor of cloning an early human, writes Zach Zorich in Archaeology magazine, is that it could provide clues to modern health issues:
Neanderthal cells could be important for discovering treatments to diseases that are largely human-specific, such as HIV, polio, and smallpox, he says. If Neanderthals are sufficiently different from modern humans, they may have a genetic immunity to these diseases. There may also be differences in their biology that lead to new drugs or gene therapy treatments.
Bringing a Neanderthal or Denisovan to life may be several years away, but the very idea is alarming. Would such a human be kept for life in a laboratory? If we cloned a pair, could they be bred? Could a Neanderthal or a Denisovan adapt to contemporary life? Would they be put in zoos? (We’ve done that before to “primitive people” from Africa.) Would the reborn Denisovans have legal rights?
And is playing God with our extinct forebears truly the way to cure the ills of modern civilization … or is it just another symptom of what ails us?
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And here’s a simple description, from the Huffington Post, of what the scientists found and what they’ve been doing with it.