Random Samples

Science  31 Mar 2006:
Vol. 311, Issue 5769, pp. 1843

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    CREDIT: JASON BROUGHAM, http://www.jasonbrougham.com/

    Scientists have unveiled a new dinosaur species, a sauropod, with a neck about 8 meters long. These giant dinosaurs are famous for their long necks, some of which reached almost 9 meters, that helped them forage for greenery. But the new species, excavated in Mongolia in 2002, had a remarkably long neck given its medium-sized body—judging from the six very elongated neck vertebrae that were preserved.

    The adult skeleton of the newly named Erketu ellisoni, on loan to the American Museum of Natural History in New York City, also includes most of the right rear leg, which suggests the beast stood only some 3 meters high at the hip. Daniel Ksepka, a grad student at Columbia University, who with the museum's Mark Norell describes the fossil in the current issue of American Museum Novitates, speculates that the species' long necks “helped them exploit different resources.” But these were not treetop resources; scientists say that sauropods couldn't walk around like giraffes, as their neck vertebrae would have been dislocated. Ksepka says the new sauropod may help clear up the evolutionary relationships of early forms of this group of sauropods, the Titanosauriformes.


    “This is an innovative effort by the Lancaster School District to propel science education out of the 19th century and into the 21st century.”

    —Alex Branning, president of a group called Integrity in Academics, after the board of the Lancaster School District, in suburban Los Angeles, voted last week to adopt a policy stating that evolution should not be taught as an “unalterable fact.”



    Only about two-thirds of depressed people feel better after taking antidepressants, and currently, doctors have no way of knowing who is likely to benefit. Now a team led by psychiatrist Francis McMahon of the National Institute of Mental Health in Bethesda, Maryland, has identified a gene variant that appears to enhance a person's odds of responding to Prozac and other selective serotonin reuptake inhibitors (SSRIs).

    McMahon and colleagues analyzed DNA samples from 1953 patients with major depressive disorder who were being treated with the SSRI citalopram (Celexa). Looking at 768 markers within 68 candidate genes, they found only one marker—in a gene coding for the 2A serotonin receptor—that was significantly associated with response to the drug. Everyone has two copies, or alleles, of the gene, which comes in two versions, A and G. The researchers found that 80% of patients with two A alleles got better on the drug, compared to 62% of those with two G's.

    The finding could help explain why blacks appear to have a poorer response than whites to antidepressants, the authors say in a report to be published in May in the American Journal of Human Genetics. Of the 313 blacks in the study, only 6% had at least one A allele, whereas 42% of the whites did. And people with two A's (14% of whites and 1% of blacks) did much better than those with only one, says co-author Dennis Charney, a psychiatrist at Mount Sinai Medical Center in New York City.

    “This work presages a revolutionary future for psychiatry where choice of antidepressant treatment will be determined in part on an individual patient's genotype,” says psychiatrist Eric Nestler of the University of Texas Southwestern Medical Center in Dallas. McMahon adds that future research will look at the entire genome, including genes involved in drug metabolism.



    Archaeologists working in the Ethiopian desert last month found a hominid skull they believe to be some half-million years old. Sileshi Semaw of Indiana University, Bloomington, who is director of excavations at a site called Gona, announced the find last week in Addis Ababa. The skull, which is missing a jaw, could be tremendously important because fossils from this era—the Middle Pleistocene—are exceedingly rare. Yet this is the crucial time when modern Homo sapiens emerged from Homo erectus.

    Paleoanthropologist Tim White of the University of California, Berkeley, says the closest hominid skull in time and place is from another Ethiopian site, the Middle Awash. Known as Bodo, it was found in 1976. But White says the Bodo skull had a more massive face and brow ridge than the current find. “Once again, the Afar [region] has yielded a very important fossil that is going to figure prominently in our ability to understand human evolution when it's been dated and studied,” he adds. Semaw and his team say they are optimistic about getting a secure age for the fossil because of the many distinct layers of volcanic ash in the area.