Drawing of a woolly mammoth. A large genetic study of the extinct woolly mammoth has revealed that the species was not one large homogenous group, as scientists previously had assumed, and that it did not have much genetic diversity. "The population was split into two groups, then one of the groups died out 45,000 years ago, long before the first humans began to appear in the region," said Stephan C. Schuster, associate professor of biochemistry and molecular biology at Penn State University and a leader of the research team. "This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction." The discovery will be published later this week in the early online edition of the Proceedings of the National Academy of Sciences (PNAS).

Flies, unlike humans, can't manipulate the temperature of their surroundings so they need to pick the best spot for flourishing. New Brandeis University research in this week's Nature reveals that they have internal thermosensors to help them.

Researchers at Tufts University School of Medicine and Tufts Medical Center have found that Smad proteins regulate microRNA (miRNA) processing. Understanding the role of Smad proteins enables researchers to investigate abnormal miRNA processing which is a contributing factor in development of cardiovascular disorders and cancer. The study was published online today in Nature.

A team of scientists from the University of Georgia and two European universities has, for the first time, synthesized and characterized the elusive parent molecule of an important class of chemical compounds.

Scientists have discovered that there are more bee species than previously thought. In the first global accounting of bee species in over a hundred years, John S. Ascher, a research scientist in the Division of Invertebrate Zoology at the American Museum of Natural History, compiled online species pages and distribution maps for more than 19,200 described bee species, showcasing the diversity of these essential pollinators. This new species inventory documents 2,000 more described, valid species than estimated by Charles Michener in the first edition of his definitive The Bees of the World published eight years ago.

The temperature inside a healthy, photosynthesizing tree leaf is affected less by outside environmental temperature than originally believed, according to new research from biologists at the University of Pennsylvania.

The proteins upon which life depends share an attribute with paper airplanes: Unless folded properly, they just won't fly.