Genetics Suggest Modern Female Came First

W A S H I N G T O N,  Nov. 14 -- Science may have caught up with theBible, which says that Adam and Eve are the ancestors of allhumans alive today.

But in the scientists’ version, based on DNA analysis, “Adam,” the genetic ancestor of all men living today, and “Eve,”the genetic ancestor of all living women, seem to have livedtens of thousands of years apart.

How could this be?

Peter Underhill and colleagues at Stanford University inCalifornia have an explanation. “They had different molecularclocks,” Underhill said in a telephone interview. “Fewer menparticipated in reproduction than women did.”

Tracing Women to Earlier Time

His team, working with top geneticists across the UnitedStates, Europe, Israel and Africa, did a genetic analysis of DNAsamples from the Y chromosomes of more than 1,000 men from 22geographic areas and determined that their most recent commonancestor was a man who lived in Africa around 59,000 years ago.

Only men have Y chromosomes and researchers can look atgradual genetic mutations in them to “count” generations.

Other studies have used mitochondrial DNA, which women seemto pass down virtually unchanged from mother to daughter, toshow that the genetic “Eve” lived 143,000 years ago.

The latest study, published in the November issue of thejournal Nature Genetics, reconciles the two findings, and in theprocess the researchers came up with new tool for looking at howpeople are different from one another genetically.

They also added a great deal of detail to the family tree ofall men living today, information that can be used byhistorians, anthropologists and other researchers. “We can lookat the tree and see, ‘Oh, this section of the tree is whereAsians go.’ We can say, ‘Oh, here is a Japanese Y chromosome andthis is a Chinese Y chromosome,’” Underhill said.

Race Not Evident in Genetics

What the tree does not do, he stresses, is identifyso-called races. Geneticists have long agreed there is nogenetic basis to race — only to ethnic and geographic groups.