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Wednesday, March 5, 2014

Neanderthal Man


The hottest thing in human evolution studies right now is DNA extracted from fossils of Neandertals and other long-gone populations. Pääbo, the dean of ancient-gene research, explains in his book how it all began when he bought a piece of calf liver at a supermarket in 1981.
In those days, DNA had been successfully pulled only from living animals. Pääbo modified the methods to extract genetic material from the dead calf’s liver, which had been heated to make it hard and dry like an Egyptian mummy. Pääbo then retrieved human DNA from an actual Egyptian mummy. A high-profile journal published his findings.
After that auspicious start, the Swedish scientist recounts how he came to run the world’s first laboratory studying ancient DNA. A recurring theme in the book concerns Pääbo’s obsessive push to eliminate sources of contamination in ancient DNA, especially modern human DNA transmitted by scientists who handle (and in one case, licked) fossils.
Pääbo describes professional tensions that flared in 2006 when his team chose a technique to sequence the Neandertal genome. Researchers who had developed an early method of extracting DNA from fossils lost out to developers of a simpler but more powerful procedure. Feelings were hurt. The leader of the snubbed research group became a competitor of Pääbo’s for Neandertal bones and for bones from Neandertal relatives called Denisovans.
Aside from such behind-the-scenes dramas, Pääbo provides a fascinating look at how his personal life 

Saturday, March 1, 2014

Creature power



Sometime in the future: A patient leaves the hospital with a new pacemaker implanted next to her heart to steady its beat. Her older brother, who went through the same procedure a few years earlier, will soon need another major surgery to replace his pacemaker’s batteries. But she won’t. Her device can generate its own electricity indefinitely with sugar and oxygen harvested from her bloodstream.
Scientists are racing to perfect the technology that could make this possible. If they succeed, these “biological fuel cells” could usher in a new wave of medical devices smaller and more versatile than today’s batteries allow.