Researchers use DNA to identify turtle eggs

SAVANNAH, Ga. --- On a recent Sunday morning, Tammy Smith knelt in a sand dune at Tybee's north beach and dug down to where a loggerhead sea turtle had laid her eggs.

Gently, Ms. Smith removed a single leathery orb from the pit.

Then she did something that would've been unthinkable just a year ago.

She cracked open that egg.

"I really don't like doing that," she said.

Ms. Smith buried the egg's contents and squeezed the pliable shell into a labeled test tube filled with rubbing alcohol.

Scenes like this have been repeated more than 900 times along Georgia's coast this summer as an extraordinary collaboration of volunteers, students and professional researchers helps to catalog the identity of every turtle that nests in the state.

Researchers at the Applied Genetics Lab at the University of Georgia have developed a technique that allows them to get a genetic fingerprint of each mother turtle from a sample of her DNA left in an eggshell membrane.

"It's like CSI for sea turtles," said Joe Nairn, a molecular biologist and associate professor at the University of Georgia.

Mr. Nairn's doctoral student, Brian Shamblin, last year tested the methods he helped develop, comparing turtles' skin samples to those in a pilot egg study.

It worked.

Now, instead of having to rely on catching a turtle in the nocturnal act of nesting and radio-tagging it, researchers can get a fix by taking a sample from each of the already highly monitored nests along the Georgia coast.

For those who worry about removing an egg from the nest of each loggerhead, a threatened species, Georgia sea turtle coordinator Mark Dodd says don't. It's statistically insignificant.

"The hatch success is 60-80 percent," he said. "Taking one egg is not going to change the hatch success."

By next summer, researchers will know how many turtles visited the Georgia coast, how many times each turtle came back, and where she nested each time. They'll also know how many of those turtles are sisters or cousins.