COLUMBUS, Ohio, March 17 (UPI) -- U.S. scientists have developed a new, lean mouse that might lead to controlling obesity and related disorders by manipulating a specific protein.

To create the hybrid, Ohio State University researchers crossed mice deficient in protein kinase C beta with the C57 black mouse -- a common animal used in research for studying diabetes and obesity.

"These animals can eat more than normal and they have less fat than normal," said Professor Kamal Mehta, the study's senior author. "That's a dream come true if it can (eventually) be extended to human beings."

The hybrid mice not only appear smaller and leaner, the researchers found they have less fat distribution in their skin and less fat tissue overall. The fat cells they did have were found to be smaller than fat cells in other mice.

And the new mice lost weight while eating up to 30 percent more food than other mice. That, the scientists said, suggests the protein deficiency corrected for the obesity tendencies by increasing the hybrids' ability to burn fat.

The study, which included researchers Rishipal Bansode, Wei Huang and Sanjit Roy, appeared in a recent issue of the Journal of Biological Chemistry.

Scientists propose new DNA nanosensor

SAN DIEGO, March 17 (UPI) -- U.S. scientists have used a mathematical simulation to show how a DNA sensor might be coupled with a nanoscale transistor to find DNA fragments in a sample.

Researcher Samuel Afuwape of San Diego's National University said such a portable DNA sequencer could make life easier for environmental scientists testing contaminated sites. Clinicians and medical researchers might also use such a device to diagnose genetic disorders and study problems in genetics. A similar sensor might also be used to identify the weapons of a bioterrorist or in criminal forensic investigations.

While DNA biosensors are becoming ubiquitous in many areas, Afuwape said the instrumentation is usually limited to the laboratory setting. He suggests a new type of electronic device, the ion-selective field-effect transistor might be integrated into a DNA biosensor. Such a portable sensor would be coated with thousands of known DNA sequences that could match -- hybridize -- with specific DNA fragments in a given medical or environmental sample.

The complex research appears in the International Journal of Nanotechnology.

Donkey domestication is documented

ST. LOUIS, March 17 (UPI) -- A U.S.-led team of scientists has found evidence of the earliest transport use of the donkey and the early phases of donkey domestication.

The findings by the team led by Professor Fiona Marshall at Washington University in St. Louis suggest the process of domestication might have been slower and less linear than previously thought.

The research focused on 10 donkey skeletons from three graves dedicated to donkeys in the funerary complex of one of the first pharaohs at Abydos, Egypt.

Marshall, in collaboration with Stine Rossel of the University of Copenhagen, found donkeys approximately 5,000 years ago were in an early phase of domestication. They looked like wild animals, but displayed joint wear that showed they were used as domestic animals.

"Genetic research has suggested African origins for the donkey," said Marshall. "But coming up with an exact time and location for domestication is difficult because signs of early domestication can be hard to see. Our findings show that traces of human management can indicate domestication before skeletal or even genetic changes."

The research appeared in the March 10 early online edition of the Proceedings of the National Academy of Sciences.

Study finds how an eye can determine depth

ROCHESTER, N.Y., March 17 (UPI) -- U.S. scientists have discovered how the human brain can derive depth information using just one eye.

Researchers led by Professor Greg DeAngelis of the University of Rochester noted when we use two eyes, the brain calculates the depth or distance of an object from the slight differences in the two images of the object by a phenomenon called "binocular disparity."

Although scientists also knew people could judge distance using just one eye, the mechanism by which the human brain accomplished that feat has been unknown.

DeAngelis said neurons in the middle temporal area of the brain calculate distance by combining visual information from the eye with information about the physical movement of the eye.

"It looks as though in this area of the brain, the neurons are combining visual cues and non-visual cues to come up with a unique way to determine depth," said DeAngelis. He said the brain, when tracking the movement of a group of objects, use middle temporal neurons to calculate the object moving fastest in the same direction must be the closest object and the one moving slowest must be the farthest.

The study's findings appear in the online issue of the journal Nature.