The 1,000 Genomes Project, which began in 2008, was an international effort to create a detailed and publicly accessible catalog of human genetic variation to support medical studies aimed at exploring genetic contributions to disease. Project scientists sequenced the entire genomes of 2,504 individuals from around the world—more than the 1,000 originally planned. The Project extended the results of the International HapMap Project, a prior effort at cataloging human genetic variation that ran from 2002 through 2010. Whereas the HapMap identified common genetic variants, meaning specific DNA sequences present in five percent or more of individuals in a population, the 1,000 Genomes Project identified genetic variants present in as few as one percent of individuals in a population. By assembling a larger catalog of DNA sequence variation than had previously existed, the 1,000 Genomes Project paved the way for researchers to more precisely locate disease-related genetic variation passed from parent to child.