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Finding One's Roots

Publication Date: 
October 07, 2007
CBS News: 60 Minutes
Lesley Stahl

Professor Henry T. "Hank" Greely is interviewed by 60 Minutes' Lesley Stahl about the limitations of the emerging field of genetic genealogy:

Hank Greely, a law professor at Stanford University, has studied this new field. He worries that people don't realize just how many ancestors they actually have.

"Eight generations ago both you and I had 256 great-great-great-great-great-great grandparents," Greely points out. "It doubles every generation. So you've got two parents. You have four grandparents. You have eight great grandparents. Sixteen great-great grandparents. And it adds up fast. It adds up so fast in fact that if you go back 20 generations you've got over a million grandparents."

1,048,576 to be exact. And in each generation, DNA testing can provide information about only two of them.

"So you could be Peruvian on your mother's mother's mother's side, Japanese on your father's father's father's side. Swedish on everything else," Greely explains.

"And you'll never know?" Stahl asks.

"And you'll never know the Swedish from the 'y' chromosome or the mitochondrial DNA," Greely says.

Greely says he has looked at several companies that are doing these tests. Asked if he thinks that they adequately explain the limitations, Greely says, "No. I don't think any of them does as good a job of pointing out the limitations. But, you know, businesses often don't go around telling you how weak their product is."


Asked if he thinks there is any fraud involved here, Greely tells Stahl, "I don't think there's fraud. I think there is hype."

"You know, beer commercials imply that drinking their beer will make beautiful women fall all over you. I think the genetic genealogy companies don't go below the normal standards of the marketplace. But they don't go above it either," Greely says. "Some do a better job than others, but there's not one that couldn't improve. And that bothers me because they're using science to sell their product. And science is about the whole truth."