U.S. is growing more genetically diverse

BALTIMORE — The American melting pot is more flavorful than ever, a new study reveals.

Except for a dip in the 1940s, genetic diversity in the United States has been increasing every decade since 1920, Amir Kermany, a computational biologist at AncestryDNA, reported October 9 at the annual meeting of the American Society of Human Genetics.

Americans are increasingly choosing mates with ethnic backgrounds different from their own, Kermany and colleagues found after analyzing DNA from more than 800,000 AncestryDNA customers born in the United States between 1920 and 2010. The researchers looked for genetic variants characteristic of heritage from six continents. Generations of people born more recently are more genetically diverse — carrying ancestry from more than one ethnic group or continent — than their parents and grandparents, the team found.

But “we’re still far from random mating,” Kermany said. “Although more people are crossing ethnic lines, there is still a strong bias to mate with someone of the same ethnicity.”