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First look at humans’ ancient cousin, the prehistoric Denisovans

Reuters, AP, September 22, 2019 6:45PM Kids News

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A statue reconstruction of a young female Denisovan based on a skeletal profile reconstructed from ancient DNA. Picture: Hebrew University via AP media_cameraA statue reconstruction of a young female Denisovan based on a skeletal profile reconstructed from ancient DNA. Picture: Hebrew University via AP

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Scientists have reconstructed the skull of a prehistoric, extinct cousin of humans, so we can see, for the first time, what these people looked like.

To recreate the skull and other parts of the skeleton of a Denisovan, the scientists in Israel used the DNA* found in a tiny pinky-finger bone of a 13-year-old girl who lived 70,000 years ago.

media_cameraThe reconstruction of the skull and skeleton of the Denisovan girl was based on this tiny piece of pinky finger bone, seen here sitting on the hand of a modern human.

Little is known about the Denisovans and their existence was only recently discovered. Modern people did not evolve from Denisovans or Neanderthals, although our species, Homo sapiens, interbred* with both.

Evidence of Denisovans was first uncovered in 2008 in a cave in Siberia*, where they may have lived between 200,000 and 50,000 years ago.

Today, all we have of this species is three teeth, the pinky bone and a lower jaw, said genetics professor Lian Carmel from Hebrew University. Israel.

Prof Carmel said that was enough to create a model of a full Denisovan skeleton.

“This is the first time that we provide a detailed anatomical* reconstruction showing us what these humans looked like,” he said.

It turns out, Prof Carmel said, “we are all very similar.”

media_cameraLiran Carmel of the Hebrew University speaks to journalists before revealing a 3D-printed model of the face of a Denisovan. Picture: AFP
media_cameraLiran Carmel reveals the 3D-printed model of the face of a Denisovan. Picture: AFP

His team developed a technology to understand the ancient DNA and, more importantly, how the genes* on that DNA acted. Gene activity, for example, differentiates between a frog and a tadpole, even though their DNA is identical, he said.

DNA could indicate the Denisovan’s dark skin, eyes and hair, Prof Carmel said, but by mapping gene activity patterns, they could understand how the species stood out anatomically from modern humans or Neanderthals. They identified 56 traits*, most in the skull, that differed.

This helped them produce a rendering* — claiming 85 per cent accuracy — of a Denisovan skeleton that at first glance looks like it could be from a modern human, though differences are obvious on closer inspection.

There were similarities to Neanderthals — a sloping forehead, long face and large pelvis* — but the Denisovans were also unique in their very wide skull and large dental arch.

The skeletal reconstruction, along with an artist’s rendering of the 13-year-old girl’s head and face, were published in the journal Cell.

media_cameraA preliminary portrait of a young female Denisovan. Picture: Hebrew University via AP

The team repeated the process as a test with Neanderthals and chimpanzees, whose anatomies are known, and found the reconstruction to be 85 per cent accurate. The discovery of more Denisovan DNA would further improve the reconstruction.

Bence Viola of the University of Toronto, Canada, who studies Denisovan fossils, called the work “a huge step forward … This would have been called science fiction five years ago.”

Some remote modern Asian populations have Denisovan DNA, suggesting this extinct species lived over a broad area.

Research suggests that Denisovan DNA may have contributed to modern Tibetans’ ability to live in high altitudes and the Inuits’ ability to withstand freezing temperatures.

media_cameraAnother portrait of a young female Denisovan based on the skeletal profile reconstructed from ancient DNA. Picture: Hebrew University via AP

GLOSSARY

  • DNA: the information in the cell of a living thing that tells it how to grow and function
  • interbred: male and female from two species had children
  • Siberia: a huge region across northern Russia and northern Asia
  • anatomical: relating to the structure of the body
  • genes: information on physical traits that is passed from parent to child, genes contain DNA
  • traits: features or characteristics
  • rendering: drawing
  • pelvis: big bone that wraps around the lower body, includes the hips

EXTRA READING

Ancient jawbone solves mountain puzzle

Meet our mysterious lost ancestors

Ancient human species discovery

QUICK QUIZ

  1. How long ago could the Denisovans have lived in the Siberian cave?
  2. Where is Siberia?
  3. What distinct features did the Denisovans have?
  4. What does Bence Viola think about the Denisovan reconstruction?
  5. What do you now know about some modern humans ability to live at high altitude?

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