Saturday, December 20, 2008

Neanderthals' Cellular Overheating May Have Led to Their Extinction

Meet Wilma, the first model of a Neanderthal based in part on ancient DNA evidence. Click here for National Geographic information on her image and additional photos.

Neanderthals may have produced so much internal heat that a steadily warming climate caused their extinction about 24,000 years ago.

Scientists at Newcastle University in England have put forward the theory after examining a particular form of genetic material obtained from the fossilized bones of Neanderthals. By comparing it with that found in modern humans, they discovered that Neanderthals had key differences in the sections responsible for producing energy in all living cells.

Professor Patrick Chinnery, a neurogeneticist at Newcastle University, believes the differences in this mitochondrial DNA could have caused Neanderthals to be inefficient at producing energy, meaning their cells leaked heat.

Searching for Genetic Clues

"The question is why did Neanderthals disappear?” he told the Telegraph of London. “There are lots of explanations to do with changes in climate and the food supply. Differences in these mitochondrial DNA sequences might explain why modern humans were able to survive while Neanderthals were not.

"We found a number of differences within a certain part of the mitochondrial DNA that were quite unlike anything we see in modern humans,” he said. “It is difficult to get a definitive answer, as it is rather like looking through a misty window. We can only get clues to what went on."

Genome Research Continuing

Mitochondria are tiny structures found inside all living cells and are the biological power stations that produce the energy cells need to survive by converting sugar from food into energy.

Scientists have also been attempting to read the entire Neanderthal genome in the hope that it will shed more light on the differences between them and modern humans. Recent work by scientists at the Max Planck Institute in Germany revealed that Neanderthals shared a language gene that is only found in modern humans. The controversial findings raised the debate about whether Neanderthals were capable of speech.

Neanderthals are thought to have evolved from a common ancestor shared with modern humans around 400,000 years ago. It is thought they died out around 10,000 years after modern humans began spreading in Europe.

Click here for the complete Telegraph article.

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