SCIENCE UPDATE
One single little finger bone has provided American scientists with the genetic information required to produce the first portrait of this extinct human species.
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A jawbone, some teeth, and a little finger bone: those were the only fragments available to scientists from Stanford University in the US who were working to establish the likely physical appearance of Denisovans – the human species that co-existed with Neanderthals and Homo sapiens up until at least 40,000 years ago. Thanks to the successful extraction of DNA, they now have a theory which can compare the Denisovan skeleton and skull with the bone structure of Neanderthals and modern man.
Scientists examined DNA from the small finger bone, which came from a Denisovan girl who lived 40,000 years ago. Molecules known as methyl groups on DNA strands can identify whether a gene is active or not, allowing the scientists to identify which genes were active in Denisovans and to compare these with active genes in our own species and those from known samples of Neanderthal DNA. The study uncovered 56 differences by which the Denisovans diverged from Neanderthals and modern man, 32 of which would result in anatomical differences relating to the development and strength of bones in different parts of the body. The Denisovans had wider pelvises and chests than modern man, but narrower, flatter faces than Neanderthals. The upper skull was broader in Denisovans than in either Neanderthals or humans, though generally a Denisovan skull was closer to that of a Neanderthal – flatter than ours with a low forehead and powerful brow ridges.
To test the method’s accuracy, the scientists made the same comparisons with chimp DNA, with the differences they found correctly predicting 85% of anatomical features.