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24/12/2010

X Woman genome sequenced; Determining age form blood samples; Moments of Genius - Professor Barry Marshall on Kary Mullis; Ice-Age fossils; Gene for impulsivity

X Woman genome sequenced
Scientists have sequenced the genome of an ancient hominid female from just the finger-bone found in Denisova cave in southern Siberia. She is nicknamed 'X Woman' - thought to have been living in Central Aisa around 48,000 and 30,000 years ago. Earlier in the year, analysis of the mitochondrial DNA, which is only inherited down the maternal line, revealed that these 'Denisovans' shared a common ancestor with modern humans and Neanderthals about one million years ago, but that it was unlikely to have interbred with our direct ancestors and those of our ancient cousins. Now, having decoded the nuclear DNA and have much more information about this possibly new species.

Determining age form blood samples
Blood left at a scene of crime is often a good source of clues – studying the splatter pattern can help forensic experts to recreate what might have happened. The DNA can be checked against known suspects. But now it is hoped that forensic scientists may soon get even more information from blood left behind. Professor Manfred Kayser of the Erasmus University in Rotterdam, in the Netherlands has discovered an accurate and reliable way of determining the age of an individual from what are known as "T-cells" in blood.

Moments of Genius - Professor Barry Marshall on Kary Mullis and PCR
All this year we have been bringing you Moments of Genius - scientific inspiration from the past. The final moment comes from Australian physician Professor Barry Marshall who won the Nobel Prize for Medicine in 2005 for his work that proved that a bacteria rather than stress and bad diet caused peptic ulcers. He describes the moment in 1983 when Kary Mullis worked out how to make millions of copies of DNA using the Polymerase Chain Reaction or PCR.

Ice-Age fossils
A seven-foot mastodon tusk, the 100 kilogramme skull of a bison, and the tooth of an ancient sloth are just some of the recently discovered ice-age fossils that are keeping scientists at the Denver Museum of Nature and Science, in Colorado in the US, incredibly busy. They have unearthed more than 600 ice age fossils, including the remains of insects and plants. The discovery is being thought of as an entire ecosystem frozen in time.

Gene for impulsivity
You might think that impulsive behaviour or 'acting without thinking' is just an annoying trait you or some of your friends may have. But impulsivity - can have a darker side. Impulsivity has been linked to a variety of behavioural and psychiatric syndromes, including attention deficit hyperactivity disorder, mania, drug addiction and borderline personality disorder. It has also been associated with violent behaviour and antisocial personality disorders. And now it turns out, there maybe a genetic mutation for it. David Goldman from the National Institute of Alcohol Abuse and Alcoholism in Rockville Maryland reported in the journal Nature this week that they have found the mutation for impulsive behaviour in a group of people in Finland.

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