Racialized Genetics and the Study of Complex Diseases: The Thrifty Genotype Revisited

Abstract

Current debate on the use of population genetic data for complex disease research is driven by the laudable goals of disease prevention and harm reduction for all, especially dispossessed, formerly enslaved, or colonized populations. This article examines one of the oldest gene-based theories of complex disease causation: the thrifty genotype hypothesis (THG). This hypothesis is emblematic of the way in which genetic research into complex disease attracts a high investment of scientific resources while contributing little to our capacity to understand these diseases and perpetuating problematic conceptions of human variation. Although there are compelling reasons to regard the high prevalence of type 2 diabetes mellitus as a by-product of our biological incapacity to cope with modern affluent and sedentary lifestyles, there is at present no consistent evidence to suggest that minority populations are especially genetically susceptible. Nor is it clear why such genetic differences would be expected, given the original pan-species orientation of the TGH. The limitations inherent in current applications of the TGH demonstrate that genetic research into complex disease demands careful attention to key environmental, social, and genetic risk factors operating within and between groups, not the simplistic attribution of between-group differences to racialized genetics. A robust interdisciplinary approach to genetic epidemiological research is proposed.

African Genetic Diversity: Implications for Human Demographic History, Modern Human Origins, and Complex Disease Mapping

“…Prior to 10,000 years ago, all modern humans subsisted as hunter-gatherers who likely experienced frequent cycles of feast and famine. According to the thrifty gene hypothesis, ancestral genetic variants that once promoted the efficient absorption, storage, or utilization of nutrients in this ancestral environment are now maladaptive in more modern environments, increasing risk for disease (51,153). Although genetic evidence for this hypothesis has been inconclusive (34,68,214), recent data from the Macaque Genome Project indicated that a number of polymorphisms in the macaque correspond to known disease-predisposing alleles in humans (39).…”

Congenital and Environmental Factors Associated with Adipocyte Dysregulation as Defects of Insulin Resistance

“…Substantial growth and development is completed before birth, as demonstrated by the inverse relationship between birth weight and risk of diabetes and metabolic syndrome later in life [30][31][32]. The thrifty phenotype hypothesis proposes that early-life metabolic adaptations promote survival, with the developing organism responding to environmental cues by selecting an appropriate growth trajectory [33,34].…”

Frameworks of Choice: Predictive and Genetic Testing in Asia

“…Concerns include: how personal genetic data will be stored and used, including for research or 'direct marketing' of products; whether the police or governments will be given access to commercial genetic databases (Kaye 2006); and whether people will be required to reveal genetic test results to insurers or employers (Wallace 2005b). In addition, studies of the genetics of diet-related disease and appetite can detract from the social and economic factors that lead to poor health in marginalised populations (Montana 2007;Paradies et al 2007). Unless genetic testing is genuinely useful to guide treatment, promoting genetic explanations for diet-related disease can be counter-productive -wrongly implying that nothing can be done to change the situation.…”