A molecular biology technique used to trace the origins of humankind could help identify missing children kidnapped during Argentina's eight years of military rule, a geneticist said Monday.

Mary-Claire King, a professor of epidemiology at the University of California, Berkeley, said the technique involves matching highly specific bits of DNA from a child who may have been kidnapped to DNA from any one of the child's maternal relatives.King described the breakthrough in using "mitochondrial DNA" to reunite missing children with their true families during a symposium at the annual meeting of the American Association for the Advancement of Science.

According to King, every child inherits from his or her mother a highly specific sequence of DNA, found in a cellular component known as the mitochondrion. Mitochondria, located outside the cell nucleus, supply the cell's energy and are found in all but sperm cells.

The genetic sequence in this mitochondrial DNA snipped, called the "displacement loop," is so specific that a child shares the exact pattern only with his or her mother and certain other maternal relatives, King said.

King cited recent work with Cris-tian Orrego, a biochemist in Berkeley's Museum of Vertebrate Zoology, in which mitochondrial DNA sequenced from the blood of three children and their grandmothers showed without a doubt their correct biological relationships.

Using this technique, scientists and human rights activists could ultimately determine the true identity of more than 200 children kidnapped during Argentina's infamous "dirty war," King said. About 150 of those children have yet to be identified by their families.

King has been working since 1984 on methods to help identify the children, at the behest of an Argentinian human rights group, the Grandmothers of the Plaza de Mayo.

Many grandparents and other relatives of kidnap victims have now stored their DNA and genetic profiles in the National Genetics Data Bank, established by the Argentinian government.

King said mitochondrial DNA matching can prove a child's identity if it matches any one of possible maternal relatives - the relative could be a brother or sister, a maternal grandmother, great aunt or great uncle, a maternal aunt or uncle, or a cousin who is the child of a maternal aunt.