Madame Butterfly 0 Posted July 5, 2005 Experts unravel DNA of extinct cave bears Lessons could be applied to study of Neanderthals Updated: 4:11 p.m. ET June 2, 2005 WASHINGTON - Researchers have sequenced the DNA of two extinct cave bears and say their method is accurate enough to try doing it on extinct human relatives such as Neanderthals, according to a report published in Friday's issue of the journal Science. The cave bears are the first extinct animals to have their genes sequenced, and the findings can be used to determine the precise relationship between the 40,000-year-old bears and living species. But the main message is that the technique should be useful in examining Neanderthal DNA, the researchers report. "We picked cave bear as an initial test case ancient DNA target because the samples we used in the study are roughly the same age as Neanderthals," said Eddy Rubin of the U.S. Department of Energy, where some of the work was done. Extracting Neanderthal DNA "Our real interest is in hominids which include humans and the extinct Neanderthal — the only other hominid species that we have to compare with humans. Our nearest living relative is the chimp, and that's 5 million years of divergence," Rubin added in a statement. The researchers include Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who first extracted and analyzed DNA from Neanderthal bones in 1997. Paabo's team worked with mitochondrial DNA, which is found in the body of the cell and is passed down virtually intact from mothers to their children. Geneticists need nuclear DNA — the kind that is mixed together and passed along from both parents — to get a real idea of a creature's genetic heritage. To do this, the international team of researchers turned to cave bear remains from Austria. "We extracted DNA from a cave bear tooth recovered from Ochsenhalt Cave, Austria, and a cave bear bone from Gamssulzen Cave, Austria, dated at 42,290 and 44,160 years before present respectively," they wrote in their report. Comparisons to modern animals They compared the sequences with DNA from dogs, modern bears and other animals, and filtered out obvious contamination from microbes and fungi. "When people hear about our success, they immediately think about how this strategy could work for dinosaurs," Rubin said. Dinosaur DNA plays a fictional role in Michael Crichton's "Jurassic Park," a novel made into a film in which dinosaurs are resurrected using DNA taken from amber-preserved insects and cloning technology. While experts have found some soft tissue in 70 million-year-old dinosaur fossils, it is not at all clear whether any measurable DNA remains. Rubin said it may also be possible to extract DNA from the remains found in Indonesia of the Flores Man, a small Homo erectus nicknamed "the hobbit" because of its tiny stature. These remains have been dated to just 18,000 years ago. Share this post Link to post Share on other sites
