Mammoth Discovery: Decoding the Secrets of Ice Age DNA with Stephan Schuster

man holds up four fingers on both hands
Laura Stocker

Stephan Schuster

"Evolution is never frozen," said Stephan Schuster at the Penn State Downtown Theatre last Wednesday, March 31. Schuster, professor of biochemistry and molecular biology at Penn State, discussed his exciting work—sequencing the DNA of woolly mammoths—with an enthusiastic crowd of about 90 people from both the campus and community, from schoolchildren to retirees.

Schuster focused his talk on the implications that his findings have for our understanding of evolution, genetic diversity, and species preservation. "There are three important things when it comes to extinction: habitat, genetic diversity, and population size," he stated.

Noted Schuster, who worked on the mammoth genome with Penn State colleague Webb Miller, "In the past, researchers were looking at the bones of mammoths and would only be able to obtain one or two percent of their actual DNA, because the bone was filled with 99 percent bacteria." By switching to hair as a source material, Schuster and Miller were able to attain 90 percent of the mammoth's DNA. The keratin that surrounds the hair shaft acts as a protective coating, Schuster explained. "We can bleach the hair in order to destroy the bacteria and reach the hair shaft where plenty of the DNA is stored."

"The biology of extinction was discovered by man only 200 years ago," Schuster continued. "This was the first time we realized that there were species of animals that had lived before us." A mammoth carcass—named the Adams Mammoth after Michael Adams, the botanist who recovered it—was found in Siberia in 1799. It remains the most complete mammoth ever found, said Schuster, and it was from this 35,000-year-old specimen that he was able to obtain hair for analysis.

To analyze the DNA, Schuster used the most technologically advanced high-throughput DNA sequencing machine of its day: the Life Sciences 454 GS20. "Penn State was the fourth site in the world—and the first university—to have one of these innovative machines," he noted. Schuster has since used this technology to look at other species of animals, including the polar bear and the now-endangered Tasmanian Devil. "By looking at its mitochondrial diversity, we can show better ways to breed the Tasmanian Devil, and save it from extinction," he told the crowd. He also held out the possibility that some species that have suffered recent extinction might be resurrected via genetic manipulation.

Schuster suggested, "The mammoth was like the cow of the Pleistocene era. Humans needed them for food and for clothing." However it is more likely that the mammoth's extinction was a result of severe climate change, rather than human hunters, he said. "We are living in a world of changing climates that wiped out entire species of animals. We still have this problem today and we should be careful not to ignore this," Schuster explained. "The polar bear is the mammoth of our time. As an Arctic species that is faced with the threat of global warming, it might go extinct in the near future."

Please join us for our next conversation on Wednesday, April 7, "Fossil Rainforests of Patagonia: Ancient Biodiversity and Living Legacy," hosted by Peter Wilf of the Geosciences department.

Last Updated April 06, 2010