Science  28 Jan 2011:
Vol. 331, Issue 6016, pp. 384

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  1. Star Light, Star Bright


    This infrared image from NASA's Spitzer Space Telescope shows what may be the most luminous group of superstars in the entire galaxy. Such groups—named OB associations for the O and B spectral types of their hot, blue suns—sculpt vast regions of space through their radiation and supernova explosions. The newly discovered Dragonfish association in the Southern Cross is 32,000 lightyears distant and harbors about 400 hot, blue, luminous stars, Mubdi Rahman of the University of Toronto in Canada and colleagues will report in an upcoming issue of The Astrophysical Journal Letters. The stars' extreme ultraviolet radiation strips electrons from protons, thereby ionizing interstellar hydrogen gas and setting it aglow.

  2. Let's Stay Together


    Parting is such sweet sorrow that Sumatran and Bornean orangutans may have separated into distinct species more than half a million years later than previously assumed.

    Researchers have completed a draft sequence of the orangutan genome derived from 11 individuals on the islands of Sumatra and Borneo, the only places where our endangered, orange-haired relatives live in the wild. A comparison of the two species' DNA suggests they separated just 400,000 years ago, revising previous estimates of at least 1 million years ago. (They were physically separated at least 21,000 years ago, when land bridges between the two islands disappeared.) “Most previous studies used small sets of markers and a limited amount of DNA sequence,” says Devin Locke, a structural geneticist at Washington University School of Medicine in St. Louis, Missouri, and the lead author of the study, which appears online this week in Nature.

    Orangutans lead a more sedentary lifestyle than other great apes, and their DNA suggests they may evolve more slowly, too. Key drivers of evolution are stretches of DNA called retrotransposons that jump around the genome, creating new genes or altering regulation of existing ones. The new data reveal that retrotransposons known as Alu elements have moved around the orangutan genome much less than they have in the human and chimpanzee genomes (the only other two great apes to have been sequenced).

  3. Single-Digit Dino


    Meat-eating dinosaurs were very good at finding food, thus their evolutionary success over some 165 million years. But during their time on Earth, they kept losing something that might seem important: their fingers. The earliest carnivorous dinosaurs had five fingers, although only four were actually functional. Many later meat eaters had three, and evolution left the mighty Tyrannosaurus rex with only two. Now researchers have unearthed the first known dinosaur with only one finger. The new single-digit species, named Linhenykus monodactylus, was found in a roughly 80-million-year-old rock formation in Inner Mongolia, lead author Xing Xu of the Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and colleagues report online in the Proceedings of the National Academy of Sciences.

    Linhenykus, which was probably about a meter tall, belongs to a family of dinosaurs called alvarezsauroids. The team suggests that the single claw-like digit was an adaptation for digging, perhaps for insects such as termites.

  4. Frédéric Chopin's 'Madness' Diagnosed

    In 1848, Polish composer and piano virtuoso Frédéric Chopin was performing at a house in Paris when he suddenly stopped in the middle of a piece and left the stage. He later wrote to a friend that he had seen creatures crawling out of his piano. Chopin is widely viewed as a tortured artist, but a new paper suggests his eccentricities might have been due to epilepsy.

    Radiologist Manuel Vásquez Caruncho and neurologist Francisco Brañas Fernández of Xeral-Calde Hospital in Lugo, Spain, studied Chopin's writings and that of friends and pupils for descriptions of his hallucinations and wild behavior. Only a handful of neurological disorders produce the phantasmagoria that tormented Chopin, who didn't abuse drugs or alcohol. The authors rule out schizophrenia and other common psychoses because Chopin's hallucinations were visual, not auditory, and because he lacked other telltale symptoms such as eye problems or migraines. His short hallucinatory episodes are a hallmark of temporal lobe epilepsy, the team reports online in Medical Humanities.

    Other researchers call the proposal interesting but perhaps too subtle. The authors themselves admit it is difficult to be conclusive without the ability to observe Chopin himself. However, Caruncho points out, testimonies from witnesses are key in diagnosing epilepsy even today.

  5. The World's Smallest Farmers


    It's too bad they don't make microscopic overalls. A study published online last week in Nature finds that the single-celled organism Dictyostelium discoideum harvests bacteria like farmers harvest crops.

    An individual D. discoideum, or “Dicty,” amoeba cell can live independently, slurping up bacteria in the soil. When the food is gone, it joins with its comrades to form a tiny sluglike organism that wriggles to greener pastures. Once there, the slug becomes a stalk with a fruiting body (pictured)—a tiny globe on top that releases spores, each spawning a single amoeba.

    Debra Brock, a graduate student in ecology and evolutionary biology at Rice University in Houston, Texas, was studying spores from wild Dicty amoebae when she saw something she'd never seen before: bacteria in the fruiting body. To find out whether the bacteria were just an infection, she gave the spores antibiotics, then placed them on a fresh patch of bacteria. The spores that had originally harbored bacteria picked up the bugs again, indicating that they were collecting bacteria. Other experiments showed that the amoebas “planted” their new environments with bacteria and harvested them. Several animals are known to farm; some ant species tend fungi, for example. But researchers say it's surprising to find the behavior in such a simple organism.

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