Sharks, barracuda and other large predatory fishes disappear on Caribbean coral reefs as human populations rise, endangering the region's marine food web and ultimately its reefs and fisheries, according to a sweeping study by researcher Chris Stallings of The Florida State University Coastal and Marine Laboratory.

While other scientists working in the Caribbean have observed the declines of large predators for decades, the comprehensive work by Stallings documents the ominous patterns in far more detail at a much greater geographic scale than any other research to date. 

"Seeing evidence of this ecological and economic travesty played out across the entire Caribbean is truly sobering," said Associate Professor John Bruno of the University of North Carolina at Chapel Hill, who served as the PLoS One academic editor for Stallings' new paper.

The size of a specific part of the brain may help experts pinpoint when autism could first develop, University of North Carolina researchers report.

Using MRI brain scans, researchers found that the area of the brain called the amygdala was, on average, 13 percent larger in young children with autism,compared with control group of children without autism. In the study, published in the latest Archives of General Psychiatry, researchers scanned 50 toddlers with autism and 33 children without autism at age 2 and again at age 4. The study adjusted for age, sex and IQ.

"We believe that children with autism have normal-sized brains at birth but at some point, in the latter part of the first year of life, it [the amygdala] begins to grow in kids with autism. And this study gives us insight inside the underlying brain mechanism so we can design more rational interventions," said lead study author Dr. Joseph Piven.

Study is largest DNA comparison yet among continent's populations

The largest genetic study of African populations reveals a greater genetic diversity of the continent’s cultural groups than previously known, scientists say. The study also yields insight into the origins of modern humans and the ancestry of African-Americans, researchers report online in Science April 30 and also during an April 29 press teleconference.

Until now, most genetic studies have used data from just a few African groups that were assumed to reflect Africa’s genetic diversity. But the new research shows that “no single African population is representative of the diversity of the continent,” says study coauthor Sarah Tishkoff of the University of Pennsylvania in Philadelphia.

A cloned beagle named Ruppy – short for Ruby Puppy – is the world's first transgenic dog. She and four other beagles all produce a fluorescent protein that glows red under ultraviolet light. 

A team led by Byeong-Chun Lee of Seoul National University in South Korea created the dogs by cloning fibroblast cells that express a red fluorescent gene produced by sea anemones. 

Lee and stem cell researcher Woo Suk Hwang were part of a team that created the first cloned dog, Snuppy, in 2005. Much of Hwang's work on human cells turned out to be fraudulent, but Snuppy was not, an investigation later concluded.