Random Samples

Science  20 Apr 2007:
Vol. 316, Issue 5823, pp. 347

You are currently viewing the .

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution



    South Korea's cloning reputation is still not out of the woods: Seoul National University (SNU) announced on 9 April that it will investigate a paper on wolf cloning following complaints that some data are inaccurate. And the journal Cloning and Stem Cells, which published the paper in March, took it off the Web on 11 April.

    Two cloned wolves—the first of their kind—were introduced to the world on 26 March by researchers at SNU led by Byung-Cheon Lee and Nam-Sik Shin. Snuwolf and Snuwolffy, endangered gray wolf females born in October 2005, were produced by the same team that came up with Snuppy, the world's first cloned dog, using the same methods.

    Shortly after the paper appeared, members of BRICs, a scientists' Web forum, claimed that Lee manipulated statistics to exaggerate the success rate of the cloning and that a table on DNA sequence analysis contained errors. Lee admitted to miscalculations at a press conference but said they were unintentional. The university has submitted for outside analysis blood and cell samples from all parties in the exercise: the two wolves, a dog that supplied enucleated eggs, and the wolf whose DNA was inserted into the eggs. Results are expected soon.

  2. NETWATCH: Postdoc See, Postdoc Do

    Short of a personal tutor who's willing to devote weeks or months to your training, a video might be the best way to learn the subtleties of a lab procedure. This pair of sites can help biologists find or swap video how-to's.

    At the Journal of Visualized Experiments,* you'll find step-by-step demonstrations of more than 30 lab techniques, including how to isolate blood-forming stem cells or extract embryos from a mouse uterus. Launched last winter by former postdoc Moshe Pritsker and computer scientist Nikita Bernstein, the site features videos shot by professionals and vetted by scientists.

    For a YouTube-style site on subjects such as genetics and bioinformatics, go to the new LabAction from grad student Siddharth Singh of Devi Ahilya University in India. Although it has only a handful of clips so far, it aims to be fun as well as educational, with a category set aside for amusing takes on campus life.



    Until the mid-1800s, leeches were applied to treat ailments including headaches, stomach pain, obesity, fever, and even mental illness, after which their efficacy was seriously doubted.

    Today, one species, Hirudo medicinalis, is a U.S. Food and Drug Administration (FDA)-cleared device that is widely used to help reattached scalps and fingers as they grow new blood vessels. Demand for the species is great, and so is the loss of its wetlands habitat in Europe. Most now come from leech “farms.”

    But it turns out many people have the wrong Hirudo. Mark Siddall, a systematist at the American Museum of Natural History in New York City, and colleagues compared DNA from various leeches. Commercially available creatures are actually H. verbana, they reported online 10 April in the Proceedings of the Royal Society B. Siddall explains that in the 1800s, taxonomists discerned no internal differences and lumped the two species as H. medicinalis.

    But, he says, from the genetic evidence “it's unfathomable that they are the same species by any measure.” Brijitte Latrille, of the French leech supplier Ricarimpex, says both work the same magic and “I see no problem” in asking FDA to add H. verbana to its approved leech list.



    THE ANNUAL PILGRIMAGE, or haj, to Mecca in Saudi Arabia offers one of the world's greatest challenges in crowd control. The millions in attendance create a volatile environment in which pilgrims have been trampled to death performing a ceremony on the Jamarat Bridge in Mina, where they hurl stones at pillars representing the devil. In January 2006, more than 360 people were killed in a stampede near the bridge. Haj officials have since instituted new safety rules and enlarged the bridge; they have also sought advice from experts in traffic and crowd flow.

    One of these experts is Dirk Helbing, a physicist at the Technical University of Dresden in Germany, who was asked to suggest safe routes for crowd movements. Last week, he reported on this work at a physics conference at the University of Leicester, U.K. He and co-workers analyzed videotapes of the 2006 disaster, observing how thick crowds of people, like high-density flows of fluids, can turn “turbulent,” causing groups to move erratically. When this happens, people fall and get trampled. Helbing described how it is possible to identify changes in crowd behavior in advance of the turbulence and thus pinpoint danger spots.

    The changes have apparently been effective: At the latest haj, from 29 December to 1 January, there were no major incidents.