individuals are sampled from around the world in a way that reflects the geographic distribution of humans across continents, the human gene pool does not consist of continental clusters, but reflects gradients of allele frequencies across the world. This absence of major discontinuity in genetic traits is consistent with earlier research showing that most genetic variation is found among individuals and not among population groups. They concluded that “most alleles influencing susceptibility to disease or outcome of medical interventions cannot be expected to show significantly different frequencies between ‘races’.”125 Thus, although genetic markers can uniquely identify most individuals, variation in biological characteristics is not inherently structured into meaningful “racial” categories at the population level and identifying ancestry provides very limited direct information regarding whether an individual carries specific genetic traits.3, 126 It has also been noted that there is a growing trend in health disparities research to keep the logic of genetic racial differences intact but to substitute the language of “ancestral background” for the language of “race.”127
