-- A team of U.S. and German researchers has extracted mitochondrial DNA from Neandertal bone showing that the Neandertal DNA sequence falls outside the normal variation of modern humans."These results indicate that Neandertals did not contribute mitochondrial DNA to modern humans," says Dr. Mark Stoneking, associate professor of anthropology at Penn State. "Neandertals are not our ancestors."The research also reaffirms the origins of modern humans in Africa. Reporting in today's (July 11) issue of the journal Cell, the researchers detail their methods and the results of analysis of Neandertal mitochondrial DNA. The research team includes Matthias Krings, graduate student, and Dr. Svante Paabo, professor of zoology, University of Munich; Dr. Ann Stone, postdoctoral fellow, University of Arizona; Ralf W. Schmitz and Heike Krainitzki of Rhineland Museum, Bonn, Germany; and Stoneking.Current theory holds that Neandertals became extinct only 30,000 years ago and co-existed with modern humans in Europe. The team, however, found that Neandertals and modern humans diverged genetically 500,000 to 600,000 years ago, suggesting that though they may have lived at the same time, Neandertals did not contribute genetic material to modern humans.Since 1991, an interdisciplinary project of the Rhineland Museum, headed by Schmitz, has focused on the Neandertal-type specimen. This specimen was found in 1856 near Dusseldorf, Germany. As a part of this project, a sample was removed for DNA analysis."The ability to extract DNA from ancient bone is dependent on many factors, including preservation, temperature and humidity," says Stoneking, a faculty member in Penn State's College of the Liberal Arts.Paabo previously showed that even if extracting ancient DNA is possible, it tends to be damaged and degraded, yielding only short fragments. The researchers used a method of overlapping short strands of DNA to obtain a mitochondrial DNA sequence of 378 base pa...
