| 4 May 2010
Secrets of human history extracted from ancient DNA
The genes of individuals who lived thousands of years ago is providing information not only about them, but about the history of their species and ours. Genome sequencing of DNA extracted from Neanderthal remains is being used to map and compare the genetic code from early and modern humans. Dr. Webb Miller of Pennsyvania State University, a professor of biology and computer science, has lead several of these studies.
The results of these genetic maps highlight similarities and differences in basic anatomy and physiology between our species, homo sapiens, and Neanderthals, who were of the species Homo neanderthalensis. These data then allows scientists like Miller to see which prehistoric populations have contributed to modern DNA and which died out completely.
Since Neanderthals and modern humans coexisted in the same areas, a major question to be answered is whether or not any Neanderthal genes are incorporated into our genome. The Neanderthal genome project is expected to publish results soon. They may shed light on differences in brain development between the species and the evolution of speech and language.
DNA also provids information on human migration patterns. Miller reports on a recently published study of a man who lived in Greenland 4,000 years ago.His DNA shows that he was part of a group of people who had come from Northeastern Siberia one thousand years earlier. Scientists were able to determine that the man resembled modern Asians, with brown eyes and dark skin and hair, and that he may have been balding.
It is not easy to extract DNA from ancient remains. In Greenland, researchers used a tuft a hair found in permafrost. According to Miller, hair has been found to be a very good source of genetic material. The extreme cold of the enviroment contributed to the preservation of the sample. Genes also provide a rare view of our ancient ancestors. Work on a single gene in 2007 revealed that some Neanderthals may have had red hair and light skin color.
Miller is quick to point out that the goal is not a Neaderthal version of Jurassic Park. Genome sequencing between species helps in the understanding of human diseases and genetic diversity. For non-human animals, this can be used to preserve endangered species like pandas in captive breeding programs. Miller jokes that he is not trying to bring back extinct individuals. "I'm just trying to keep the ones we've got."
Source: Physorg.com (22 April 2010)
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