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Denisova Caves - Siberia

Scientists draw up definitive list of genes that make us human

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Last month we reported on the incredible accomplishment of researchers from the Max Planck Institute for Evolutionary Anthropology, who mapped the Neanderthal genome to the same level of detail that has been achieved with modern-day humans.  One of the many amazing discoveries that emerged is that there are only 87 Neanderthal genes responsible for making proteins in cells that are different from those found in modern humans.  Somewhere within those genes may be the answer to why Neanderthals became extinct, and what it is that makes us human .

Scientists have long debated about the reason Neanderthals became extinct some 40,000 years ago. Hypotheses on the fate of the Neanderthals include an inability to adapt to climate change, competitive exclusion, or extinction by encroaching modern humans.  It is possible, for example, that Neanderthals had a greater susceptibility to pathogens introduced by Homo sapiens.   Neanderthal hybridization with early modern human populations is also considered a viable hypothesis, and there is indeed genetic evidence produced by the Max Planck Institute to support the idea that this occurred to some extent. 

But despite all the possible theories, none of them have been proven definitively. One of the difficulties is that well-preserved fossils dating back 40,000 are hard to find, and Neanderthals are known to have had a physique and brain size that were very similar to modern humans .  Research has also shown that they had language, similar social structures, used similar tools, and had similar diets.  So what could account for their extinction?

The latest mapping of the Neanderthal genome may hold the answer.  Researchers have drawn up the first definitive list of genetic changes that make modern humans different from our nearest ancient ancestors.  The list amounts to a series of biological instructions that shape the brains and bodies of human beings and distinguish them from Neanderthals and other early humans that lived alongside them. Scientists are now going through the list to work out which genetic tweaks might have been most important in causing our ancient human ancestors to die out.  

"We are quite confident that among these genetic changes lie the basis for the interesting differences between modern humans and Neanderthals," said Janet Kelso, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig.

"These mutations are specific to modern humans... maybe we will find something that makes our brains tick better. If something like that exists, it will be on this list," said Kay Prüfer, the first author on the study. "

As well as the 87 genes that were found to affect proteins, the researchers found many more differences that could alter how, when or where the genes are expressed in the body.  The scientists still have a long way to go in their analysis, but it appears we may be one step closer to unravelling the mystery of one of our closest relatives.

By April Holloway

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Very interesting site on archeology.

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