WASHINGTON, Sept. 1 (UPI) -- A new map of human genetic variations will help researchers in studies aimed at finding genetic variants associated with complex diseases, U.S. scientists say.

The new map, the third generation of what has been dubbed the HapMap, includes data from an additional seven global populations, bringing the total number to 11 populations, a National Human Genome Research Institute release said Wednesday.

The increased number of samples allows detection of variants that are much rarer than could be found by the earlier HapMaps.

All humans are more than 99 percent the same at the genetic level, but the small fraction of genetic material that varies among people can help explain individual susceptibility to disease, responses to drugs or reactions to environmental factors, researchers say.

"The generated HapMap provides an important foundation for studies aiming to find genetic variation related to human diseases," NHGRI director Eric D. Green said. "It is now routinely used by researchers as a valuable reference tool in our quest to use genomics for improving human health."

The NHGRI is part of the National Institutes of Health, which provided major funding for the HapMap Project.