Meet Nifty Fifty evolutionary biologist Beth Shapiro who spends her days peering into the past. Her work in the emerging research field of ancient DNA takes her on a fascinating journey through time – collecting and studying the genetic samples of giant mammoths, saber-toothed cats, mastodons, dodo birds and other extinct animals, and piecing together such mysteries as the last ice age and the arrival of the first humans to North America.
“Ancient DNA gives us new insight into the most fundamental processes of evolution and refreshing new information about our past,” says Beth, assistant professor of Biology at Pennsylvania State University and one of the top ancient DNA scientists in the world. “A better picture of the past may help us save species today,” she says.
Other aspects of ancient DNA research also include focusing more specifically on the influences of climate change on genetic diversity within populations. In this emerging field, scientists use genetic information gleaned from the remnants of ancient animals, plants, soil and other sources to discover how evolution happens over time and territory. By analyzing DNA samples from species at not just one, but many moments in time, researchers can trace changes in populations, and overlay those changes with concurrent environmental events. The precision this allows is unprecedented.
In her work, Beth has scoured remote landscapes in Alaska, Kenya, Siberia, Canada and other locations to collect small samples from bones, teeth, skulls, and tusks that will be brought back to the lab, ground up, dissolved, altered and “cooked” so DNA can be extracted. “I do a lot of my work in the Arctic because the frozen ground preserves the bones the best,” says Beth. “We get some of our samples from museums as well.”
From samples and statistical models, ancient DNA scientists can pinpoint when a species’ genetic diversity changed, she says. “We can see if that change may have been influenced by a specific event such as a new predator or shift in climate. By sampling populations across time, we can actually see diversity being lost or gained as animals evolve and disperse.”
Over the years, there have been many hypotheses about why populations maintain or lose diversity. “Now, for the first time, ancient DNA lets us explicitly test those hypotheses and propose new ones. Answering these questions can help form strategies to protect and conserve species today,” Beth adds. Already, ancient DNA has proved several long-standing assumptions wrong. “It was commonly accepted that the reason bison have no diversity today is that almost all of them were killed by human hunters in North America 200 years ago,” Beth notes. Instead, her ancient DNA analysis proved that even when there were millions of bison, they had very little genetic diversity. In fact, their decline began not 200, but 35,000 years ago as climate changed and they passed through the last Ice Age. In addition, by comparing DNA of the dodo with the genes of forty other species, Beth’s research established that the flightless bird was a distant relative of the pigeon. Ancient DNA has also shed new light on the decades-old debate over what caused the mass extinctions of mammoths, saber-toothed cats, mastodons, and other distinctive species about 10,000 years ago.
What ancient material do you think should be analyzed and why?
Read more about Dr. Shapiro here:
Learn more about what Dr. Shapiro is learning from ancient DNA here:
For a more in depth lecture watch here: