The study, based on scans of the whole human genome, is the most thorough to look for patterns corresponding to major geographical regions. These regions broadly correspond with popular notions of race, the researchers said in interviews.
The researchers did not analyze genes but rather short segments of DNA known as markers, similar to those used in DNA fingerprinting tests, that have no apparent function in the body.
The study, published today in Science, finds that ''self-reported population ancestry likely provides a suitable proxy for genetic ancestry.'' In other words, someone saying he is of European ancestry will have genetic similarities to other Europeans.
Several scientific journal editors have said references to race should be avoided. But a leading population geneticist, Dr. Neil Risch of Stanford University, argued recently that race was a valid area of medical research because it reflects the genetic differences that arose on each continent after the ancestral human population dispersed from its African homeland.