Genetic Adam and Eve Lived Together: DNA Reveals Common Ancestor

Scientists may have tracked down the origins of the biblical Adam--sort of. By studying the Y chromosomes of men from many different populations, researchers have discovered that their male most recent common ancestor (MRCA) lived sometime between 120,000 and 156,000 years ago.

The original ancestor for the X chromosome has been tracked down before by studying DNA carried down through the human race's female line. This woman probably lived between 99,000 and 148,000 years ago, which correlates nicely with the recent findings. Yet actually tracking the Y chromosome wasn't easy. Technical limitations previously limited scientists in their search for MRCA.

The scientists used Y chromosomes obtained through the Human Genome Diversity Project and from other sources. In all, it included chromosomes from 69 men in several populations in sub-Saharan Africa, Siberia, Cambodia, Pakistan, Algeria and Mexico. After studying and tracing back these chromosomes, the researchers were able to determine when the MRCA existed.

So what does this mean exactly? The findings could help researchers better understand great migrations. Our human ancestors in Africa spread out across Asia and Europe and, eventually, into the Americas. Tracing back the genetics of these populations could allow scientists to understand a little bit more about our ancient past.

"We're interested in understanding the historical relationships between many different human populations, and the migration patterns that have led to the peopling of the world," said Jeffrey Kidd, one of the researchers, in a news release. "We hope that others will make use of this approach and sequence additional chromosomes of interest that are related to the peopling of specific places."

In addition to being able to better understand human migrations, the findings could give scientists a genetic "clock" to use when studying today's humans. It could allow researchers to understand the great genetic diversity seen across Africa, and the evolution process that led to modern humans. More importantly, though, the new research reconciles the timing of "Adam" and Eve."

"This has been a conundrum in human genetics for a long time," said Carlos D. Bustamante, senior author of the study, in a news release. "Previous research has indicated that the male MRCA lived much more recently than the female MRCA. But now our research shows that there's no discrepancy. In fact, if anything, the Y chromosome may be a bit older."

The findings are published in the journal Science.