Findings

The Scottish terrier that was a finalist at the Westminster Dog Show last week is a mutant. And she's not alone. With their stubby legs and long bodies, Scottish terriers, Bassett hounds, and dachshunds have been purposely bred by humans to have chondrodysplasia, a dwarfing of the legs that is considered a defining--and desirable--trait in some breeds of little dogs. Now, geneticist Elaine Ostrander of the National Human Genome Research Institute in Bethesda, Maryland, and her colleagues have identified the underlying genetic variant that truncated these dogs' legs and made it possible for dachshunds, for example, to burrow down a hole to hunt badgers.

As she showed glossy images of her photogenic canine subjects, Ostrander described how researchers have been seeking genes that explain the origins of diversity in the 300 known breeds of dogs, which come in all shapes and sizes, with long hair and short fur, smashed faces and long snouts. In 2007, Ostrander's lab found a single gene in short dogs, such as Chihuahuas and Pekingese, that regulated the expression of insulin-like growth factor 1 (IGF-1); the gene was missing in giant breeds, such as bullmastiffs and great Pyrenees.

So what about those funny legs?

Chocolate shakes with nano-silica. Low-fat, full-flavored mayonnaise. What are the benefits and risks of using nanotechnology in food? The Science podcast examines the issue. 

Malaria grips many of the impoverished regions throughout the world, killing between 700,000 and 2.7 million people each year. And as Earth warms, researchers only expect the problem to get worse. But at a symposium here yesterday, entomologist Matthew Thomas of Penn State University, University Park, said the story may not be that simple. Researchers have been ignoring the fact that temperatures vary throughout the day, he says, and when these daily fluctuations are taken into account, they show that predicted incidences of malaria can be off by 50% to more than 100%.

Temperature is critical to malaria's spread. A mosquito picks up the Plasmodium parasite that carries the disease when it bites an infected human, and it carries the parasite in its gut, where it matures--a process that takes about 10 to 14 days at about 25°C. At temperatures below about 16°C, the parasite doesn't mature fast enough, and the mosquito dies before it can pass it on. Temperatures above 40°C kill the parasite.

So where did scientists go wrong?

How can putting your feelings into words dampen those feelings?  And what does it mean when a chimpanzee smiles?  Find out in this podcast from Science podcaster Robert Frederick.

As a crowd of kids lean in to look, intrepid Julia Rademacher Wedd, 7 years old, steps onto a low plastic stool and places her hand on a contraption that resembles a large steel mushroom. Then, a switch is flipped, electrically charging the device, and one long dirty-blond hair after another rises from Julia's head. She glances at herself in a hand-held mirror and smiles.

Julia, a first grader from the Hyde Park section of Chicago, was the latest in a long line of schoolchildren who have been electrified by the Physics Van, a traveling science outreach program staffed by a volunteer crew of undergraduate physics majors from the University of Illinois, Urbana-Champaign. And on Sunday afternoon here, the Physics Van exhibit was a main attraction for Family Science Days, a weekend-long science extravaganza geared mostly to the under-18 set, something of a cross between a toy store, a trade show, and a hands-on science museum with a replica dinosaur.

People today can live long enough for three and sometimes even four generations to interact. But did Neandertals know their grandparents? At a symposium Friday, Rachel Caspari of Central Michigan University argued that the answer is no.

Caspari analyzed a trove of 120,000-year-old Neandertal fossils from the site of Krapina in Croatia. Excavated more than 100 years ago, the assemblage contains bones of 75 to 83 individuals, which apparently accumulated within 10,000 to 20,000 years. Caspari estimated their age at death from the teeth; in young people, teeth are generally pristine, while the enamel is worn away in older people. And over time, a tooth's pulp cavity shrinks as additional dentine is deposited into it. In a new method, Caspari used nondestructive micro CT scans to measure pulp cavities.

What would the replication of DNA look like as a dance? How about the neural mechanisms of language processing? An audience was treated to exactly this on Friday night at the debut performance of THIS IS SCIENCE, the culmination of the AAAS/Science Dance Contest.

In the front row were the four scientists who won the contest last year: Sue Lynn Lau, Miriam Sach, Vince LiCata, and Markita Landry. In November, the YouTube dance interpretations of their Ph.D. theses beat out three dozen other contenders, and tonight was their reward. For the past several months, they have been collaborating with professional choreographers to turn their published research into a professional dance. Tonight was the first face-to-face meeting between the four scientists and the choreographers.

The videos of the dances will be published here in March at www.gonzoscientist.org. But in the meantime, here is a sneak preview. The two dangling dancers pictured here represent subunits of DNA polymerase in action, spinning as they weave fresh genetic material.

--John Bohannon

Science podcast host Robert Frederick sits down with ScienceNOW editor David Grimm to discuss some of the highlights of the AAAS meeting so far.  Listen to the conversation here.

Emotions were mixed as Chinese and U.S. scientists mounted the stage today for "Disaster Scene Investigation: Lessons of the Wenchuan Earthquake." On 12 May 2008, a magnitude-7.9 quake leveled 5.5 million homes and killed 70,000 people in western China. The region is still struggling to recover. "It was a terrible tragedy," said Richard Stone, Science's Asia bureau chief and organizer of the session. "But for scientists, it has turned out to be a unique laboratory for understanding killer earthquakes and how to prepare and respond to the next one." Stone joined scientists at the scene within a week of the disaster.

Luckily, the area hit by the quake was wired with one of the world's densest broadband seismometer arrays, with nearly 300 solar-powered detectors recording tremors in the ground. It delivered a flood of data to a team led by geologist Liu Qiyuan of the China Earthquake Administration in Beijing. What's more, the unstable fault line where the quake originated has now been mapped and modeled in unprecedented detail. Here at the AAAS meeting, Liu, Cui Peng of the Institute of Mountain Hazards and Environment in Chengdu, and a U.S. colleague, MIT geologist Leigh Royden, gave an overview of their analysis.

Thanks to a particle accelerator the size of a football field, paleontologist Paul Tafforeau of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, was able to touch a 100-million-year-old wasp. It wasn't a real bug, but a larger-than-life plastic reconstruction made possible by shooting x-ray beams up to a billion times brighter than a hospital x-ray at ancient pieces of amber. A three-dimensional plastic printer made the model, which Tafforeau said at a press conference today is better than any virtual representation on a computer. "You can feel it in your hands."  

Long-extinct insects, corroded ancient bronzes, parchments too delicate to unroll--these are some of the ancient objects that the world's most advanced x-ray facilities, including ESRF, are bringing to light. The x-rays at a synchrotron pick up speed by flying around a doughnut-shaped vacuum chamber, hundreds of meters in circumference. That results in an extremely bright, highly focused beam, which a computer processes into an ultrahigh-resolution image, all without damaging the sample.

So what other secrets from the past are emerging?