Common Origin Cited for American Indians

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Common origin cited for American Indians

The vast majority of American Indians most likely descended from a single migrating population from Asia, biochemist Douglas C. Wallace told a scientific gathering last week in Bar Harbor, Maine.

With that assertion, Wallace enters the long-running debate over who first settled in the New World. Much recent attention has focused on the linguistic research of Stanford University's Joseph Greenberg, who argues that Native American languages fall into three groups that descended from one ancestral tongue (SN: 6/9/90, p.360).

"Our findings support Greenberg's hypothesis," Wallace told SCIENCE NEWS. "If we go back far enough in time, most American Indians should genetically link up with one Asian population."

Wallace and his co-workers at Emory University in Atlanta studied mitochondrial DNA from South America's Ticuna Indians, Central America's Maya and North America's Pima. A total of 99 individuals, each with a different maternal ancestry, donated blood for genetic analysis.

Mitochondrial genes lie outside the nuclei of cells and are inherited only from the mother. Using DNA-cutting enzymes to snip mitochondrial samples at specific locations, the researchers pinpointed chemical sequences at those locations.

All three tribes have high frequencies of mitochondrial DNA containing at least three of four rare chemical sequences, two of which otherwise occur only in Asian populations, Wallace reports. Early Asian immigrants to the New World must have carried the four "master" sequences with them, he maintains. Moreover, most modern American Indians apparently descended from at least four women in an early migrating group, he adds. …