Scientists probe ‘Fountain of Youth’ hormone• Texas researchers have found a naturally occurring hormone that can extend the lifespan of mice by as much as 30 per cent, a discovery that opens a new avenue of research into human longevity. But the hormone decreases fertility and increases susceptibility to diabetes, the team reported in the online edition of Science. The hormone — called Klotho after one of the Greek fates who controlled the length of human life — is produced in the brain and kidney in a variety of species, but leaks out into the blood stream. The hormone is also found in humans, and researchers are now beginning to look to see if long-lived people have above-average levels in their blood. Gene variation suggests brain is still evolving• Scientists have discovered a gene variation, perhaps involved in brain size, that showed up only 6,000 years ago — a mere blink of the eye in evolutionary time. This discovery, along with another brain gene that arrived about 37,000 years ago, is providing scientists with strong evidence that the human brain is still a work in process. “It’s very exciting stuff,” said Henry Harpending, a professor of anthropology at the University of Utah. The new study was led by Bruce Lahn, a Howard Hughes Medical Institute investigator at the University of Chicago, and appears Friday in the journal Science. Analyzing DNA samples from individuals throughout the world, they identified two genetic varieties that are unique to humans. One called abnormal spindle-like microcephaly, or ASPM, first appeared 6,000 years and is now found in 30 per cent of the population. The other, called microcephalin, evolved about 37,000 years ago and has spread to more than 70 per cent of the population. “We tend to think that we have reached the pinnacle of evolution,” Lahn said. “Given these findings, we can say that the human brain is still changing — and rather rapidly. In 10,000 years, the biological processes may be very different than they are today.” — Agencies
