SVTR

http://www.nature.com/news/2007/070305/full/070305-7.html

Published online: 7 March 2007; | doi:10.1038/news070305-7

Dozens of new cancer genes found

Genome sweep shows cancer-driving mutations more common than thought.

Michael Hopkin

Scientists have identified hundreds more genes that are active in cancer cells. Dr David Becker/Wellcome Trust Medical Photographic Library

The range of mutations that can drive cancer growth could be much wider than thought. An international research effort called the Cancer Genome Project has identified around 120 new genes that contain mutations promoting the disease.

"This is a lot more cancer genes than we expected to find," says Michael Stratton of the Wellcome Trust's Sanger Institute in Cambridge, UK, one of the leaders of the research.

The researchers used data generated by the human genome project to sift through a family of 500 genes, called kinase genes, linked to cell growth and division. Defects in some of these genes have already been linked to cancer.

This is a lot more cancer genes than we expected to find.  Michael Stratton, Wellcome Trust Sanger Institute

Using cell samples from 210 different types of cancer, they searched for mutations in the genes of these cells that are not present in those of non-cancerous cells. They found more than 1,000 cancer-specific mutations, of which around 150 are thought to be 'driver' genes, which trigger the rampant growth of cancer cells. The researchers report their findings in this week's Nature¹.

 

http://www.nature.com/news/2007/070305/full/070305-6.html

Published online: 7 March 2007; | doi:10.1038/news070305-6

Did a 'light' genome help birds take flight?

A smaller genome evolved in dinosaurs, long before birds learned to fly.

Lucy Odling-Smee

Tyrannosaurus rex may have had the genetic 'lightness' to permit flight, long before their descendents took to the skies. NHPA

A study of dinosaur genomes hints that the early evolution of a smaller genome might have been necessary for later vertebrates to take to the skies.

Birds have long been known to have much smaller genomes than mammals and reptiles living on the ground. And a small genome has been linked to both small cell size and high metabolic rate: the lower volume-to-surface ratio of small cells, which don't have much DNA to pack inside, can allow for faster transport of nutrients and signals across the membrane. Thus, some suggest that the energetic demands of flight require birds to have a 'light' genome.

But which came first: flying birds or the smaller genome?

 

http://www.nature.com/news/2007/070305/full/070305-10.html

News

Published online: 8 March 2007; | doi:10.1038/news070305-10 Rose-scented sleep improves memory Bursts of scent during the night can help solidify learning. Kerri Smith Forget me not: a floral scent can help trigger memory formation during sleep. Getty It's often said that optimistic people look at the world through rose-tinted spectacles. Now it seems that rose-tinted smells can have benefits too. Taking a whiff of rose scent while learning a task and then being exposed to the same smell during sleep helps memories to set, researchers have found. The discovery could see students frantically spraying themselves with perfume before exams - although the effect is tricky to replicate at home. Jan Born of the University of Lübeck and his colleagues exposed people to the smell of roses one evening while they learned the locations of various picture cards laid in a square. Half of them were then given the same odour to smell as they slept, while the other half had an odour-free night. When they were tested the next day, those who'd had a rosy sleep remembered 97% of the locations - without the roses this figure was 86%. The team's findings, published in Science1, supports theories about how memories are solidified in the brain during sleep. Researchers think that a part of the brain called the hippocampus is like the scratch-pad of memory, where we put new things that have been experienced or learned until they can be filed for long-term storage. During sleep, these memories are 'reactivated' and transferred to the cortex. Odours are known to have a potent effect on the hippocampus. Born and his team speculated that an odour could thus help to trigger the 'reactivation' process during sleep, making permanent memory storage more efficient. Their tests support this theory. "By experimentally inducing it, we can show that reactivation enhances memory," says Born.

... For students, simply revising what you have to learn and then getting a good night's shut-eye might prove infinitely more practical.

The smell trick is useful only for certain types of learning. It won't be useful for remembering the skills needed for playing the piano or riding a bike, for example, because these activity-related memories don't rely on the hippocampus.

... Born's group published a study in Nature last year that showed an increase in memory when people's brains were stimulated with a mild electric current2. "Everyone's afraid of shocking the brain," he says. "Odour presentation is a much 'softer' method."

http://www.ens-lyon.fr/Planet-Terre/Infosciences/Geodynamique/Volcanisme/Articles/massif-central.htm#1

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