According to the Wellcome Trust in the United Kingdom that runs the project, the 1000 Genomes Project is a scientific effort to sequence the genomes of at least 1,000 people to understand and create the most detailed and medically useful catalog of human genetic variation to date—hopefully to be used in future studies of people with particular diseases. They can do this for a good reason: any two humans are more than 99 percent the same at the genetic level—but the very small percent that is not the same can tell a great deal about such things as susceptibility to disease or even reactions to environmental factors. Although the goal started with 1,000 people, by 2011, the project increased its sequencing to include 2,500 genomes, sourced from about twenty different populations around the world. For example, populations being sequenced include Chinese in the metropolitan Denver, Colorado area; Japanese in Tokyo; Maasai in Kinyawa, Kenya; people of Mexican ancestry in Los Angeles; Utah residents with ancestry from northern and western Europe; and people of African ancestry in the southwestern United States.

Sir Francis Galton (1822–1911), a cousin of Charles Darwin, founded eugenics. After reading Darwin’s work on natural selection, Galton thought that the human species could be improved by artificial selection—the selective breeding for desirable traits (which was already a method used for domesticated animals). In Galton’s plan, those with desirable traits would be encouraged to have large families, while those with undesirable traits would be kept from breeding. However, Galton’s theory overlooked two important points: the importance of environmental factors and the difficulty of removing recessive traits from the gene pool. Recessive alleles can be passed from one individual to the next as part of a (heterozygous) genotype, thereby escaping detection for generations. Galton’s work was enthusiastically adopted in both the United States and Europe: In the United States between 1900 and 1930, eugenics gave rise to changes in federal immigration laws and the passage of state laws requiring the sterilization of “genetic defectives” and certain types of criminals, while unfortunately, in Europe, eugenics became a cornerstone of the Nazi movement.