Gene found to be crucial for formation of certain brain circuitry
Using a powerful gene-hunting technique for the first time in mammalian brain cells, researchers at Johns Hopkins report they have identified a gene involved in building the circuitry that relays signals through the brain. The gene is a likely player in the aging process in the brain, the researchers say. Additionally, in demonstrating the usefulness of the new method, the discovery paves the way for faster progress toward identifying genes involved in complex mental illnesses such as autism and schizophrenia—as well as potential drugs for such conditions. A summary of the study appears in the Dec. 12 issue of Cell Reports.
"We have been looking for a way to sift through large numbers of genes at the same time to see whether they affect processes we’re interested in,” says Richard Huganir, Ph.D., director of the Johns Hopkins University Solomon H. Snyder Department of Neuroscience and a Howard Hughes Medical Institute investigator, who led the study. “By adapting an automated process to neurons, we were able to go through 800 genes to find one needed for forming synapses—connections—among those cells.”
AP:A new DNA study published Thursday indicates dogs originated in Europe some 19,000 to 32,000 years ago.
This large DNA study aligns with the earliest known doglike fossils, which also came from Europe. Other DNA studies have suggested that dogs originated in east Asia and the Middle East.
Scientists agree that dogs became the first domesticated animals after emerging from wolves.
Photo: This photo provided by the Center for American Archaeology on Nov. 12, 2013 shows canine bones buried at the Koster site in Greene County, Ill.(AP Photo/Center for American Archaeology, Del Baston)
Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries. In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years. The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found. The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery. “Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study. (via Baffling 400,000-Year-Old Clue to Human Origins - NYTimes.com)