Posted on July 21, 2011

Genome Maps May Spot Disease In African-Americans

Joe Palca, NPR, July 21, 2011

Two independent teams of researchers have come up with the most accurate genetic maps ever made–a feat that should make the search for genes associated with diseases easier.


{snip} The trick to making a genetic map is to make road signs in DNA to tell you where you are.

John Novembre, a geneticist at UCLA, says one way to make road signs is to look for what are called recombination events.

“What you’re trying to do is identify locations along the chromosome where the DNA that a person inherits from their mother is different from the DNA they inherited from their father,” Novembre says.

And where that switch in a strand of DNA from one parent’s DNA to the other parent’s DNA occurs is called a recombination event.


What makes these genetic maps particularly interesting is they were developed using DNA from African-Americans. Most maps created so far are based on DNA from people of European ancestry. [Harvard geneticist David] Reich says using African-American DNA revealed something unexpected.

“There’s a family of about 2,500 hot spots of recombination that are active in people of West African ancestry, like African-Americans, which are almost completely inactive in people of non-African ancestry,” Reich says.

Finding these 2,500 hot spots could be particularly helpful for finding genes for diseases that are more common in African-Americans.