Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: FRIDAY, May 26, 1995                   TAG: 9505260097
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A-12   EDITION: METRO 
SOURCE: Associated Press
DATELINE: WASHINGTON                                LENGTH: Medium

FIRST WE HAD `AFRICAN EVE'; NOW IT'S HOMELESS ADAM

A study tracing the genetic roots of humanity suggests that the first common male ancestor - the father of us all, some might call him - evolved 270,000 years ago. This is the same era that other researchers give for the ``African Eve.''

Robert L. Dorit of Yale University said the new research also shows that in the history of life on Earth, mankind is of very recent origin and all people are virtually identical from a genetic viewpoint.

``Except for superficial things, we're all alike,'' he said. Human beings, he added, ``are the new kids on the block so far as the Earth is concerned. We're noisy, but new.''

Dorit and two co-authors looked for humankind's common male ancestor by seeking genetic mutations in a specific part of the Y chromosome, which is passed only from father to son.

Through ape studies, Dorit said, it is known that a segment of the Y chromosome mutated at a set rate over thousands of generations. By measuring these mutations in a representative population of living men, Dorit said, it is possible to calculate backward in time to a point where all human beings shared the same male ancestor.

A report on the study is to be published today in Science, the journal of the American Association for the Advancement of Science.

The study involved the genetic analysis of 38 men representing every major population group and race. Dorit said researchers were startled to find that all of them shared exactly the same pattern for the target portion of the Y chromosome. This suggested that the pattern has not been in existence long enough to go through the expected gene changes, he said.

And because human beings are new, Dorit said, there has not been time for much genetic variety to develop.

``The differences between us, as socially striking as we may wish to make them, are largely irrelevant from a biologist's standpoint,'' he said.

Dorit's finding is consistent with a 1991 study that traced female ancestry through worldwide mutations of genetic material inherited only from mothers. That study showed the first common female ancestor lived about 200,000 years ago in Africa. The Dorit study was unable to suggest a geographic origin for the universal father.

Mark Stoneking of Pennsylvania State, an author of that study, said the new research strengthens his ``African Eve'' findings. ``They got essentially the same results that we got,'' he said.

But Mike Hammer, a genetics expert at the University of Arizona, said the Dorit study is flawed and far from the final word. To truly trace the genetic roots of humankind, he said, researchers need to test DNA from more than 38 men and to analyze other parts of the Y chromosome.