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Archive - Feb 10, 2010

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Genome of Ancient Human Is Sequenced

Using sophisticated DNA sequencing technology and powerful data analysis tools, an international team has succeeded in sequencing approximately 80 percent of the genome of a 4,000-year-old sample from a man who lived in Greenland and belonged to an extinct culture (Saqqaq) that was the first to settle in the New World Arctic. The sequencing was achieved using DNA obtained from a permafrost-preserved tuft of hair. According to the research team, led by Dr. Eske Willerslev and his graduate student Morten Rasmussen at the University of Copenhagen’s Centre of Excellence in GeoGenetics, this marks the first time that a detailed reconstructed genome of an ancient human has been published. The scientists have named the ancient human "Inuk," which means "man" or "human" in Greenlandic. The genome sequence serves as a blueprint that scientists can use to give a description of how the pre-historic Greenlander looked--including his tendency to baldness, dry earwax, brown eyes, dark skin, the blood type A+, shovel-shaped front teeth, and that he was genetically adapted to cold temperatures, and to what extent he was predisposed to certain illnesses. This is important as, aside from four small pieces of bone and hair, no human remains have been found of the first people that settled the New World Arctic. Dr. Willerslev's team was also able to determine that Inuk's ancestors crossed into the New World from north-eastern Siberia between 4,400 and 6,400 years ago in a migration wave that was independent of those of Native Americans and Inuit ancestors. Thus, Inuk and his people left no dependents behind among contemporary indigenous people of the New World. “Our findings can be of significant help to archaeologists and others as they seek to determine what happened to people from extinct cultures,” Dr. Willerslev said.

Owls Chattier on Moonlit Nights

An international team of scientists from Spain, Finland, and Portugal recently discovered that eagle owls (Bubo bubo) communicate with each other using a patch of white throat plumage that is repeatedly exposed during each call and is only visible during vocal displays. The scientists found that the owls use moonlight to increase the conspicuousness of this visual signal during their call displays. Call displays were found to be directly influenced by the amount of moonlight, with silent nights being more frequent during periods with no moonlight versus those with moonlight. Furthermore, high numbers of calling bouts were more frequent at moonlight. Finally, call posts were located on higher positions on moonlit nights. The researches said that their results support the idea that moon phase affects the visual signaling behavior of this species, and provide a starting point for examination of this method of communication by nocturnal species. This work was reported on January 20, 2010, in PLoS ONE. [PLoS ONE article]

Bees Prefer Nicotine and Caffeine in Nectar

Bees prefer nectar with small amounts of nicotine and caffeine over nectar that does not contain these substances at all, according to results of a recent study from the University of Haifa in Israel. “This could be an evolutionary development intended, as in humans, to make the bee addicted,” stated Dr. Ido Izhaki, one of the researchers who conducted the study. The researchers emphasized, however, that their study has proved a preference, not an addiction, and they are currently conducting additional studies to determine if bees do indeed become addicted to nicotine and caffeine. Flower nectar is primarily composed of sugars, which provide energy for the potential pollinators. But the floral nectar of some plant species also includes small quantities of substances known to be toxic, such as caffeine and nicotine. Nicotine is found naturally in floral nectar at a concentration of up to 2.5 milligrams per liter, primarily in various types of tobacco trees. Caffeine is found at concentration levels of 11-17.5 milligrams per liter, mostly in citrus flowers. In the nectar of grapefruit flowers, however, caffeine is present in much higher concentrations, reaching 94.2 milligrams per liter. In order to examine whether bees prefer the nectar containing caffeine and nicotine, the researchers offered artificial nectar that contained various natural sugar levels and various levels of caffeine and nicotine, alongside “clean” nectar that included sugar alone. The caffeine and nicotine concentrations ranged from the natural levels in floral nectar up to much higher concentrations than found in nature. The results showed that bees clearly prefer nectar containing nicotine and caffeine over the “clean” nectar. The preferred nicotine concentration was 1 milligram per liter, similar to that found in nature.