NEUROSCIENCE: Factor Discovered to Spur Axon Growth in Upper Motor Neurons
One day, scientists hope to repair, replace, or regenerate brain motor neurons connecting to the spinal cord damaged by disease or trauma. In an early step toward that goal, Jeffrey Macklis and P. Hande Ozdinler have found a molecule that in mice prompts rapid and extensive axon growth in the corticospinal motor neurons that connect the spinal cord to the brain. The findings appear in the November Nature Neuroscience.

PATHOLOGY: Healthy Life Extended in Obese Mice
A compound that increases the life span of yeast, worms, and fruit flies now appears to improve health and survival in mice fed a high-calorie diet. The study, published online in Nature on Nov. 1, is the first in a series by the lab of David Sinclair (left) to determine resveratrol’s effect in mammals. The researchers, with co–first author Joseph Baur, report that mice treated with resveratrol, a plant-derived molecule found in red wine, avoided many of the health consequences of obesity, even though they gained weight.

GENETICS: Stable Across Time and Species, Primeval DNA May Be Chromosome Counter
Buried in the chromosomes of every vertebrate are hundreds of stretches of DNA so unchanged that they could be the genetic equivalent of living fossils. How have these identical sequences resisted the force of random mutation and natural selection? In the October Nature Genetics, Chao-ting Wu (left), Adnan Derti, and colleagues report a tantalizing clue. Running millions of computer-generated matches, they found that these primeval sequences are strikingly depleted in stretches of the genome that have undergone segmental duplications or deletions. On this basis, the researchers propose that these ultraconserved elements may be involved in carrying out one of the most essential, and earliest, of cellular activities—ensuring that a diploid cell has no more than two copies of each chromosome.