Geospatial distribution and population substructure of subgroups of US ethnic minorities: implications for perpetuation of health disparities and paucity of precision medicine

Substructure due to familial-associated divisions exists in all large populations. Geographical heterogeneity in US ethnic minorities is a function of historical, social, political, and economic factors overlaying regional geographical biodiversity. Using geospatial, historical, demographic, genetic, and epidemiological databases, we identify 40 US microethnic isolates across the US, the “minorities within ethnic minorities” and locate their geospatial distributions within the US. Key components of the environment relevant to health disparities are identified and elaborated in terms of their impact on genomics. US ethnic minority microethnic isolates often have distinct genetic and social histories from the US ethnic majority that put these isolates at a disadvantage in the quest for access to relevant, precision medicine because of the magnitude of imbedded (North Atlantic Euro-American) bias in the existing databases. However, these microethnic isolates are also at a disadvantage when simply aggregated with their nearest ethnic minority macroethnic group (e.g., generic African American). The use of geospatial and ethnographic analyses has the potential to accelerate the accurate identification of heretofore disadvantaged subgroups of ethnic minority groups, bringing them into the mainstream of genomic diversity studies and healthcare acces

Ethnogenetic Layering as an Alternative to the Race Model

Background: Traditionally, studies in human biodiversity, disease risk, and health disparities have defined populations in the context of typological racial models. However, such racial models are often imprecise generalizations that fail to capture important local patterns of human biodiversity. Aim: More explicit, detailed, and integrated information on relevant geographic, environmental, cultural, genetic, historical, and demographic variables are needed to understand local group expressions of disease inequities. This paper details the methods used in ethnogenetic layering (EL), a non-typological alternative to the current reliance of the biological racial paradigm in public health, epidemiology, and biomedicine. Subjects and methods: EL is focused on geographically identified microethnic groups or MEGs, a more nuanced and sensitive level of analysis than race. Using the MEG level of analysis, EL reveals clinical variations, details the causes of health disparities, and provides a foundation for bioculturally effective intervention strategies. EL relies on computational approaches by using GIS-facilitated maps to produce horizontally stratified geographical regional profiles which are then stacked and evaluated vertically. Each horizontal digital map details local geographic variation in the attributes of a particular database; usually this includes data on local historical demography, genetic diversity, cultural patterns, and specific chronic disease risks (e.g. dietary and toxicological exposures). Horizontal visual display of these layered maps permits vertical analysis at various geographic hot spots. Results and conclusions: From these analyses, geographical areas and their associated MEGs with highly correlated chronic disease risk factors can be identified and targeted for further study