Scientists have made ordinary human skin cells take on the chameleon-like powers of embryonic stem cells (2), a startling breakthrough that might someday deliver the medical payoffs of embryo cloning without the controversy.
The "direct reprogramming" technique avoids the ethical, political and practical obstacles that have stymied attempts to produce human stem cells by cloning embryos.
Scientists prize embryonic stem cells because they can turn into virtually any kind of cell in the body. The cloning approach -- which has worked so far only in mice and monkeys -- should be able to produce stem cells that genetically match the person who donates body cells for cloning. That means tissue made from the cells should be transplantable into that person without fear of rejection.
Monday, November 26, 2007
Man-sized Sea Scorpion claw found
Scientists have discovered an immense fossilized claw of an 8-foot sea scorpion. The 390-million-year-old specimen was found in a German quarry.
The creature, which has been named Jaekelopterus rhenaniae, would have paddled in a river or swamp. The size of the beast suggests that spiders, insects, crabs and similar creatures were much larger in the past than previously thought.
The eurypterids (sea scorpions) are believed to be the extinct aquatic ancestors of modern land scorpions and possibly all arachnids (the class of animals that also includes spiders).
The creature, which has been named Jaekelopterus rhenaniae, would have paddled in a river or swamp. The size of the beast suggests that spiders, insects, crabs and similar creatures were much larger in the past than previously thought.
The eurypterids (sea scorpions) are believed to be the extinct aquatic ancestors of modern land scorpions and possibly all arachnids (the class of animals that also includes spiders).
Sunday, November 25, 2007
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