The Complex Relationship of Genetic Ancestry With Self‐Reported Race/Ethnicity

Race and ethnicity are demographic constructs used to characterize individuals in biomedical research, and in particular to assess health disparities. Their use in medicine and research has been discussed and challenged, as well as the degree to which they represent strictly social constructs, or ones also with biological meaning. The relationship of race and ethnicity with genetic ancestry has also been described, and how genetic ancestry reflects historical continental isolation, migration, and mating structure. Race and ethnicity are currently most often assessed by self-report in epidemiology and biomedical applications. Here we further interrogate the relationship between how people self-report their race and ethnicity and their genetic ancestry by examining self-report patterns of 97,671 individuals who are participants in the Kaiser Permanente Northern California Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort. Genetic ancestry was determined from a set of 43,988 SNPs from genome-wide genotyping arrays. We observed that rates of self-identification as African American, East Asian and Latino(a) rise dramatically with a modest amount of African, East Asian and Native American genetic ancestry, respectively. By contrast, the rate of self-identification as White rises only when the European/West Asian genetic ancestry is substantial. This indicates that the majority of people who are genetically admixed, even those with primarily European/West Asian genetic ancestry, self-identify with the minority race/ethnicity group. By contrast, self-report as Native American did not increase with Native American genetic ancestry; instead, it was positively correlated with European genetic ancestry, with only a small minority of individuals self-reporting Native American race/ethnicity having Native American genetic ancestry. These results differ dramatically from the other minority race/ethnicity groups. These findings have important implications on how the different self-report race/ethnicity groups are considered in epidemiologic and biomedical research.