An international team of scientists has created the world’s largest catalogue of Human genomic variation among humans, providing researchers with powerful clues to help them establish why some people are susceptible to various diseases. For the 1,000 Genomes Project, the investigators examined the genomes of 2,504 people from 26 populations across Africa, East and South Asia, Europe and the Americas.

In the end, the scientists identified about 88 million sites in the human genome that vary among people, establishing a database available to researchers as a standard reference for how the genomic make-up of people varies in populations around the world.

Of the more than 88 million variable sites identified, about 12 million had common variants that were likely shared by many of the populations. The study showed that the greatest genomic diversity is in African populations, consistent with evidence that humans originated in Africa and that migrations from Africa established other populations around the world.

The catalogue more than doubles the number of known variant sites in the human genome, and can now be used in a wide range of studies of human biology and medicine, providing the basis for a new understanding of how inherited differences in DNA can contribute to disease risk and drug response. The findings were detailed in two studies published online in the journal Nature.