Researchers have discovered a new fact about hooded seals, a mysterious mammal that spends all but a few days each year in the ocean.

An international team of researchers led by Dr. David Coltman, an evolutionary geneticist at the University of Alberta, have learned that all the hooded seal populations in the world share the same genetic diversity. The researchers reached their conclusions after analysis of more than 20 years of DNA samples taken from hundreds of hooded seals from around the world.

"These results mean that if you brought me a DNA sample of a hooded seal, I wouldn't be able to tell you where in the world you got that sample because of the genetic similarity between populations," Coltman said.

A new study by NASA scientists suggests that greenhouse-gas warming may raise average summer temperatures in the eastern United States nearly 10 degrees Fahrenheit by the 2080s.

"There is the potential for extremely hot summertime temperatures in the future, especially during summers with less-than-average frequent rainfall," said lead author Barry Lynn of NASA's Goddard Institute for Space Studies and Columbia University, New York.

A new study examines the use of tissue-engineered scaffolding made of cartilage cells, which have a limited ability to heal naturally, to replace defective cartilage tissue. Cartilage cells are extracted and seeded to the scaffold which is implanted into the body, where new cartilage tissue is grown along the structure. The study appears in the journal Artificial Organs.

A new vaccine aimed at preventing cervical cancer is nearly 100 percent effective against the two types of the human papillomavirus (HPV) responsible for most cases of cervical cancer. Results of a nationwide study of the vaccine will be published in the May 9 issue of the New England Journal of Medicine.

Cervical cancer is the second most common cause of cancer deaths in women worldwide, resulting in nearly half a million diagnoses and 240,000 deaths each year. Every day in the United States ten women die from cervical cancer, according to Kevin Ault MD, associate professor of obstetrics and gynecology at Emory University School of Medicine, and one of the study authors.

Researchers at the Johns Hopkins Kimmel Cancer Center have conclusive evidence that human papillomavirus (HPV) causes some throat cancers in both men and women. Reporting in the May 10 issue of the New England Journal of Medicine, the researchers found that oral HPV infection is the strongest risk factor for the disease, regardless of tobacco and alcohol use, and having multiple oral sex partners tops the list of sex practices that boost risk for the HPV-linked cancer.

An international team, led by researchers at the Broad Institute of MIT and Harvard, and supported by the National Institutes of Health (NIH), today announced the publication of the first genome of a marsupial, belonging to a South American species of opossum. In a comparison of the marsupial genome to genomes of non-marsupials, including human, published in the May 10 issue of the journal Nature, the team found that most innovations leading to the human genome sequence lie not in protein-coding genes, but in areas that until recently were referred to as "junk" DNA.

Using an innovative statistical approach, a research team from Washington University School of Medicine in St. Louis and the University of California, Los Angeles, has identified two regions of DNA linked to autism. They found the suspicious DNA with a much smaller sample of people than has been used traditionally in searches for autism genes.

Researchers have known for decades that certain neurodegenerative diseases, such as mad cow disease or its human equivalent, Cruetzfeldt-Jakob disease, result from a kind of infectious protein called a prion. Remarkably, in recent years researchers also have discovered non-pathogenic prions that play beneficial roles in biology, and prions even may act as essential elements in learning and memory.

The presence of ecologically distinct males and females greatly increases a species' niche, say researchers.

Some Caribbean lizards' strong sexual dimorphism allows them to colonize much larger niches and habitats than they might otherwise occupy, allowing males and females to avoid competing with each other for resources and setting the stage for the population as a whole to thrive. The finding, reported this week in the journal Nature, suggests sex differences may have fueled the evolutionary flourishing of the Earth's wildly diverse fauna in a way not previously appreciated by scientists.

A plateau on Mars known as Home Plate shows evidence of long-past explosive volcanic activity, say scientists on NASA's Mars Exploration Rover mission. And data collected during the rover Spirit's initial pass across the 90-meter (295 feet) wide plateau also supports earlier findings indicating that water once existed at or beneath the planet's surface.