Academic journal article Mankind Quarterly

The Role of Biological 'Race' in Understanding Genetic Disease

Academic journal article Mankind Quarterly

The Role of Biological 'Race' in Understanding Genetic Disease

Article excerpt

Much research into ethnic health inequalities seeks to explain these phenomena in terms of some ethnic groups suffering cultural and socioeconomic disadvantage. Although these factors undoubtedly influence ethnic minority health outcomes, this review explores what is currently understood about the biological causes of health inequalities between ethnic groups. These health outcomes are considered within the context of the evolutionary mechanisms underlying such differences. The article then explores limitations of the 'race' concept and considers its appropriate application within the settings of biomedical research and clinical decision making.

Key Words: Continental population groups; Genetic diseases; Evolution.

The Meaning of 'Race'

The validity of biological 'race' is one issue for which scholars across different disciplines have failed to reach an adequate consensus. In some disciplines, namely sociology and cultural anthropology, the concept of biological 'race' has been largely dismissed as an arbitrary and meaningless tool of discrimination and subjugation (Montagu, 1975). The word 'race' has instead been replaced by 'ethnicity' to describe a social combination of language, culture and identity. Even in medicine, some clinicians have dismissed the concept of 'race' as an arbitrary and subjective mode of human classification (Schwarz, 2001). Many researchers, however, continue to publish data stratified by ethnic group and others have argued that ignoring 'race' will "retard progress in biomedical research and limit the effectiveness of clinical decision making" (Burchard et al, 2003). This paper discusses what is currently understood about the biological causes of health inequalities between different ethnic groups.

One definition of 'race' is a "human population partially isolated reproductively from other populations, whose members share a greater degree of physical and genetic similarity with one another than with other humans" (Random House, 2001). In this way, 'race' refers to a population in which a number of phenotypic differences are often inherited together. In terms of purely physical attributes, persons of Sudanese ancestry may be associated with darkened skin and a characteristically slim build while those of Southeast Asian origin typically exhibit short stature and epicanthal folds over the eyes (Baker, 1981). This does not, however, vindicate the popular misconception that 'races' are easily distinguishable by analysis of individual genes. As one eminent geneticist has noted, "racial stereotypes have a consistency that allows even the layman to classify individuals. However, the major stereotypes, all based on skin color, hair color and form, and facial traits, reflect superficial differences that are not confirmed by a deeper analysis" (Cavalli-Sforza et al, 1994). Indeed, examples used later in this article will include sub-populations which would not traditionally be considered to constitute a 'race'. Nevertheless, genetic analyses using multiple markers have allowed blinded researchers to construct ancestral trees, the major branches of which correspond to human 'races' (Bowcock et al, 1994; Calafell et al, 1998). This allowed CavalliSforza to construct a dendrogram showing genetic distances between each of the major racial groups (Cavalli-Sforza & Feldman, 2003). Since physical differences between 'races' reflect the selective environmental pressures of ancestral evolution, these traits occasionally coincide with genetic and cultural differences which may be used to tailor healthcare provision. Indeed, genetic analysis of individuals from 52 different populations led one team of eminent researchers to conclude that, with some limitations, "self reported ancestry can facilitate assessments of epidemiological risks" (Rosenberg et al, 2002). Furthermore, self-defined ancestry has been shown to correlate with ancestral origin (Burchard et al, 2003). Complications, of course, exist; particularly as 'races' cannot be clearly demarcated and the concept is inextricably steeped in social and cultural factors (Collins, 2004). …

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