Implications of biogeography of human populations for 'race' and medicine

Abstract

In this review, we focus on the biogeographical distribution of genetic variation and address whether or not populations cluster according to the popular concept of 'race'. We show that racial classifications are inadequate descriptors of the distribution of genetic variation in our species. Although populations do cluster by broad geographic regions, which generally correspond to socially recognized races, the distribution of genetic variation is quasicontinuous in clinal patterns related to geography. The broad global pattern reflects the accumulation of genetic drift associated with a recent African origin of modern humans, followed by expansion out of Africa and across the rest of the globe. Because disease genes may be geographically restricted due to mutation, genetic drift, migration and natural selection, knowledge of individual ancestry will be important for biomedical studies. Identifiers based on race will often be insufficient.

Balancing selection and heterogeneity across the classical human leukocyte antigen loci: A meta-analytic review of 497 population studies

“…The results presented here agree with the observation that relatively high genetic diversity (i.e., lowest F obs values) is commonly found among African populations [232]. High diversity of class I loci in NEA populations was also recently described [3], but there were insufficient data to draw conclusions at class II loci.…”

Genetic variation, classification and 'race'

“…The next cluster consists entirely of Europeans, and a final cluster contains all of the East Asian subjects and one European. The robustness and validity of these findings are supported by other studies, which, despite using different loci and different population samples, obtained similar patterns [34][35][36][37] . A statistically more sophisticated approach for cluster definition is afforded by the structure program 38 , in which individuals are first randomly assigned into one of k groups, without regard to population affiliation.…”

Genetic discovery in multi-ethnic populations

“…Indeed, classification by self-declared ancestry or by ascertainment from a specific geographic region often poorly reflects genetic reality. 8 It is important that statistical methods lead the way in using human genetic diversity effectively to understand the genomic underpinnings of disease. Studies assessing the contribution of variants to disease have shown that, in general, associated variants transcend ethnic groups, and play a role in disease susceptibility worldwide.…”