STANFORD, Calif., Aug. 3 (UPI) -- The most recent common male and female human ancestors -- so-called Adam and Eve -- lived during the same time period, U.S. and Italian researchers say.
It has generally been accepted that Eve lived about 190,000 to 200,000 years ago, while Adam lived 50,000 to 115,000 years ago, the Los Angeles Times reported Friday.
Theodore Schurr, an anthropological geneticist at the University of Pennsylvania, who was not part of either study, said that "didn't make a lot of genetic sense" -- and researchers at Stanford University in California now say Adam actually lived 120,000 to 156,000 years ago.
Researchers involved in the study said they traced the Y chromosome of 69 men living all over the world, using new technological that allows researchers to sequence more DNA cheaper and faster. They repeated the sequencing with mitochondrial DNA from women and concluded that Eve lived around 99,000 to 148,000 years ago -- and for the first time found Adam and Eve may have lived during the same time period.
In a separate study, Italian researchers used a similar approach and estimated Adam to have lived roughly 180,000 to 200,000 years ago.
"The male most recent common ancestor is just the individual whose Y chromosome happens to survive to this day, whereas those of his contemporaries have died out," said David Poznik, a geneticist at Stanford.
The same applies to women, Poznik said.
"Up until now we've done these studies with very few markers," said Paolo Francalacci, a geneticist from the University of Sassari in Italy, who led the second study. "It was like looking at a photo with a few pixels."
The new studies open "a new era of evolutionary research," Francalacci said.