Nerves of steel
The frozen remains of Otzi the Neolithic hunter contain the best-preserved nervous tissue yet discovered in an ancient human, say German biologists. Climbers stumbled on the Tyrolean ice man in the Alps in 1991. Now Michael Hess and his colleagues of the University of Innsbruck in Austria have analysed the fatty myelin sheaths that protected the man's nerve cells 5,000 years ago. Although Otzi's other body tissues show considerable decay, his nerves lasted quite well, despite repeated freezing and thawing. Hess says myelin may have survived better than other cell components because it contains more fatty molecules and less water.