News

Spencer Wells has traced his family tree back 45,000 years, to when his ancestors left Africa for the Middle East. Generations later, at the start of the last ice age, they trekked up through the grasslands of Central Asia, veered west at the foot of the ice sheet and emerged as the first "modern" Western Europeans.

Dr. Wells has been able to piece together this sketchy history because he shares pieces of mutated DNA, handed down through hundreds of generations, with indigenous groups from these regions.

The 36-year-old Texan is not an anomaly.

All humans carry genetic markers linking us back to another era, thanks to tiny mistakes in the copying process of the genome that occur between each generation.

Over the next five years, Dr. Wells, a world-renowned geneticist, and his team of researchers hope to gather one of the largest collections of human DNA, analyze it with some of the world's most powerful computers and show that humanity has taken a common journey over the past 60,000 years that leaves us all closely interconnected.

In addition to collecting and testing blood from 100,000 indigenous people around the globe, the team will also solicit anonymous DNA donations from the public over the Internet, charging individuals $100 (U.S.) each and giving them the ability to trace their own ancestry on the Web.

Public donations will be made by cheek swab samples, taken with a participation kit and mailed to the researchers. Donors will be able to connect to the on-line database and trace their own migratory history by using a special serial number that comes with the kit. As the sample builds, researchers expect the patterns to become sharper and personal histories even clearer.

"I might be able to learn something about where my ancestors a thousand years ago were living," Dr. Wells said. "I expect the story to become more interesting as time goes on. Think of it as a subscription to your own genome."

The Genographic Project is a partnership between the National Geographic Society and IBM Corp. designed to chart human development, especially in the last few thousand years, and to create a much sharper picture of the migratory history of the species and the genetic diversity of humanity.

"Ultimately, everyone around the world traces back to a common ancestor. It's by looking at the pattern of these genetic markers that have built up over time that we can trace how people are related and how their ancestors have moved around the world," Dr. Wells said.

Geneticists have already done some work in this area, but have been relying on a much smaller sample of DNA, collected from about 10,000 indigenous people. By spending tens of millions of dollars to expand the sample by at least an order of magnitude, the scientists think they will finally be able to draw some hard conclusions.

Anthropologists have debated for years, for instance, whether humans ever mated with Neanderthals in Europe 35,000 years ago. The evidence today isn't conclusive one way or the other, but findings from a sample of more than 100,000 could be, Dr. Wells says.

He isn't sure what the data will ultimately reveal. Perhaps the team will be able to find traces of Alexander the Great's armies in today's Central Asian populations. Or it might discover what impact the Inca Empire had on North and South America. "We might see evidence of the great empires of the past 5,000 years in the DNA of people living in the Middle East," he speculated.

There is a sense of urgency to the project. People are moving around the world and mixing more than ever before. Although they still carry their genetic markers, the context in which the genetic variation arose will eventually be lost.

"This is in effect a genetic snap shot of our species before we lose these signals that are carried by the indigenous populations," said Dr. Wells, who led the population genetics research group at Oxford University before becoming a National Geographic explorer-in-residence.

The decision by the researchers to solicit mail-in DNA samples from the public will not only help raise the public profile of the project but also generate significant funds. Ajay Royyuru, who is the lead scientist for IBM on the Genographic Project, estimates that "several million" people could order on-line kits.

Even though the sample won't be controlled, it will still have scientific value, he said. "It provides people with a connection to other people around the world, that they might not have realized they are related to. And raising awareness of these issues, and particularly about the indigenous populations, is a key part of the project."