RENEE MONTAGNE, HOST:
And now to what's considered the largest family tree ever scientifically mapped - it stretches back five centuries and includes 13 million people over a span of 11 generations. Published in the journal Science, the project began seven years ago after the lead researcher, Yaniv Erlich, got an email from a distant cousin through a website that shares family trees. As a computational geneticist at Columbia University, he was intrigued and asked for permission to download the data from millions of public profiles. He then charted a new road map about marriage and death. One key insight - the ability to inherit a long life appears less important than how you live that life.
Researchers estimate genes account for only about 16 percent of longevity. They also zeroed in on love. For centuries, people were rural, mostly wedding people nearby and therefore often genetically related. The Industrial Revolution created an exodus to cities, but it took until 1850 for cousins, once considered marriage material, became taboo. And two fun facts - a baby boom followed the Mayflower landing in 1620. And the research gives new meaning to degrees of connection to Kevin Bacon. Yes, he turned up on this massive family tree. Transcript provided by NPR, Copyright NPR.