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Greenwood's Expertise With Ancient DNA Places Him in the Limelight

Old Dominion University faculty member Alex Greenwood has had a busy past few weeks with the news media because of his research into the disease-related extinction of island-bound rats 100 years ago and related research into the wooly mammoth, which became extinct 10,000 years ago.

Greenwood is widely known for his research with ancient DNA. An Associated Press story distributed internationally this week noted his expertise in exploiting DNA retrieved from preserved bits of long dead animals and quoted his assessment of the recent work of other scientists to decipher much of the genetic code of the wooly mammoth.

"An amazing achievement" is how the ODU researcher described the work of the other scientists, who studied DNA from mammoth hair that was found frozen in the Siberian permafrost.

News media were quick to seize on the possibility that the deciphering of the full genetic code a decade or so from now could result in the recreation of a wooly mammoth. Greenwood received inquiries from several reporters seeking his evaluation of the report. After he talked with the AP reporter, he also did an interview that was to be broadcast on a television station in Washington, D.C.

Earlier this month, Greenwood was featured in another AP story about his research, again utilizing ancient DNA techniques, that shows disease was responsible for the extinction of rats native to Christmas Island in the late 19th and early 20th century. The findings were the first to demonstrate that disease can lead to the extinction of a mammal. According to the research, rats that were native to the island, which is in the Indian Ocean, fell victim to a pathogen brought by invasive Eurasian black rats. The Eurasian rats, which were not susceptible to the pathogen, thrived on the island after jumping ship.

Greenwood's study of Christmas Island rats also involved his colleagues in ODU's Department of Biological Sciences, Kelly Wyatt, a graduate researcher, and Wayne Hynes, interim chair and professor of biological sciences, as well as researchers at the American Museum of Natural History. Samples used in their study were from museum specimens of rats that died a century ago.

These rats were relatively modern creatures compared with the wooly mammoths that Greenwood has studied extensively. The New York Times turned to him last year when a 10,000-year-old baby mammoth was discovered remarkably well preserved in Siberian permafrost.

Some scientists raised the possibility then that mammoths might be recreated if viable eggs or DNA can be retrieved from the baby female mammoth-which was about six months old when it died on Siberia's Yamal Peninsula. One recreation scenarios suggested that elephant sperm might awaken a mammoth egg. But Greenwood told The Times then that the well-preserved state of the baby mammoth specimen by no means guaranteed that organs would be intact or that eggs would be preserved in an arrested state.

The Times article predicted that new technologies and scientific discoveries would make it more likely that that the mammoth DNA sequence will be copied. This seems even more possible now, with the latest reports of researchers. With the full sequence deciphered, the copy of mammoth DNA might take charge of an elephant egg, resulting in the recreation of the ancient animal.

Greenwood, who joined the ODU faculty in 2006, received his doctorate in human genetics from the University of Michigan and has served as a postdoctoral research fellow and research associate at the American Museum of Natural History. He also did environment and health research as a postdoctoral fellow in Munich, Germany.

He received a grant from the Jeffress Memorial Trust last year to continue his studies of mammoth population genetics. He likes to call the work "CSI: Ice Age." He also has a genetics project under way to look at why mammoths had long hair and elephants do not.

An article in Science magazine in 2000 described Greenwood's research in paleovirology, which might someday explain animal extinctions and unlock secrets of ancient viruses to the benefit of modern medicine.

This article was posted on: November 20, 2008

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