The Biologistical Construction of Race: ‘Admixture’ Technology and the New Genetic Medicine

Posted in Anthropology, Articles, Health/Medicine/Genetics, Media Archive, Politics/Public Policy, Social Science on 2012-06-03 15:22Z by Steven

The Biologistical Construction of Race: ‘Admixture’ Technology and the New Genetic Medicine

Social Studies of Science
Volume 38, Number 5 (2008)
pages 695-735
DOI: 10.1177/0306312708090796

Duana Fullwiley, Associate Professor of African and African American Studies and of Medical Anthropology
Harvard University

This paper presents an ethnographic case study of the use of race in two interconnected laboratories of medical genetics. Specifically, it examines how researchers committed to reducing health disparities in Latinos with asthma advance hypotheses and structure research to show that relative frequencies of genetic markers characterize commonly understood groupings of race. They do this first by unapologetically advancing the idea that peoples whom they take to be of the `Old World’, or `Africans’, `Europeans’, `East Asians’, and `Native Americans’, can serve as putatively pure reference populations against which genetic risk for common diseases such as asthma can be calculated for those in the `New World’. Technologically, they deploy a tool called ancestry informative markers (AIMs), which are a collection of genetic sequence variants said to differ in present-day West Africans, East Asians, Europeans, and (ideally Pre-Columbian) Native Americans. I argue that this technology, compelling as it may be to a range of actors who span the political spectrum, is, at base, designed to bring about a correspondence of familiar ideas of race and supposed socially neutral DNA. This correspondence happens, in part, as the scientists in question often bracket the environment while privileging racialized genetic variance as the primary source of health disparities for common disease, in this case between Mexicans and Puerto Ricans with asthma. With their various collaborators, these scientists represent a growing movement within medical genetics to re-consider race and `racial admixture’ as biogenetically valid points of departure. Furthermore, many actors at the center of this ethnography focus on race as a function of their personal identity politics as scientists of color. This to say, they are driven not by racist notions of human difference, but by a commitment to reduce health disparities and to include `their’ communities in what they describe as the `genetic revolution’.

The very word ‘race’ applies to a hypothetical past, or to a problematical future, not to the actual present … the only way to measure the genetic relationship of ethnic groups would be by ascertaining the quantitative values of their coefficients of common ancestry, which would be based entirely upon the statistical methods of probability theory. (We Europeans [Julian Huxley and Alfred Court Haddon, 1939: 114])

To me, the refusal to use race in medicine is political correctness gone awry. It’s a lot of white researchers gone political. (Esteban Gonzàles Burchard, asthma geneticist at the University of California, San Francisco Lung Biology Center; field notes 2003)

The Molecularization of ‘Admixture’: A History of the Present

In 1949, the year before the first United Nations Educational Scientific and Cultural Organization (UNESCO) statement rallying against the race concept, Linus Pauling characterized sickle cell anemia as the first ‘molecular disease’ (Pauling et al., 1949). At the time, most experts and lay people considered sickle cell a ‘black-race disorder’. Despite global good will and contrition for the violence perpetuated in the name of racial purification in Germany and elsewhere a few short years before, some North American scientists called the UNESCO statement an ‘incautious affirmation’ and claimed that sickle cell anemia in American blacks (who by definition, it was assumed, had white ancestry) was a perfect example of how ‘race mixture can be disadvantageous in its racial effects’ (Gates, 1952: 896). The then ‘odd’ observation that ‘hybrids’ (black Americans) seemed to have more sickle cell disease than their ‘pure’ (African) counterparts who had more sickle cell trait (which was actually mistaken for a milder form of the disease in many cases) gave immediate rise to theories that ‘racial admixture’ could affect disease risk and/or severity (Gates, 1952). With Pauling’s Nobel-winning observations came the first intellectual opening for the molecularization of race. Immediately with it came the idea that racialized ancestral mixing, or ‘admixture’, constituted increased risk of disease pathology. In what follows, I examine a present-day resurgence of the concept of human biological admixture as a factor in disease risk in some quarters of contemporary American medical genetics…

…Over the past few years, social scientists studying genetics and race have urged their colleagues to ‘go to the very sites’ of scientific production and ‘document how [racial] categories are being constructed’ anew (Reardon, 2005: 18; Duster, 2006a: 12). Following from this, it is as imperative that ethnographers also attempt to understand better scientists’ motives for wanting to resuscitate such troubled categories. To this end, it is important for me to note how my informants’ social experiences shape the tautological product of genetic racial admixture they use on a daily basis. In particular, one challenge these scientists have posed for themselves is to ‘care’ for their own disproportionately sick communities of ‘racially admixed subjects’ by recruiting and enrolling them in genetic research. A crucial aspect of their effort to reduce health disparities is a search for the biological component of these communities’ mixed racial heritage. For several of my informants, this heritage is a point of biological difference that may contain clues about present-day health differences. Here it is many ‘drops of blood’ – rather than one – that now constitute the brown bodies in question. Today, Mexicans and Puerto Ricans in the US are assumed to be differentially constituted from African-Americans and Native Americans, based on their varying amounts of African, European, and Native (pre-Columbian) genetic ancestral contributions. Yet, contrary to earlier American norms of hypo-descent, these mixed groups must remain conceptually separate, ‘ethnically’ and ‘politically’, from the referent groups that make them up. Today, Mexicans’ and Puerto Ricans’ African ancestries are deemed important for reasons that will become clear below, but they are rarely collapsed into a category of ‘blackness’. In fact, as one of the main researchers featured in this ethnography reminded himself and his team time and again, as of the 2000 census, Latinos surpassed African-Americans as the largest minority group in the US. Over the course of my fieldwork in his lab, I heard this feat by numbers repeated, as if to say that this researcher’s ‘community’ needed and deserved the same kind of attention, political courtship, and scientific resources as one of the most historically ‘important’ and visible American minority groups…

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The Genetic Structure of Admixed Populations

Posted in Anthropology, Articles, Media Archive on 2011-10-07 02:28Z by Steven

The Genetic Structure of Admixed Populations

February 1, 1991
Volume 127, Number 2
pages 417–428

Jeffrey C. Long, Professor of Anthropology
University of New Mexico, Albuquerque

A method for simultaneously estimating the admixture proportions of a hybrid population and Wright’s fixation index, FST, for that hybrid is presented. It is shown that the variance of admixture estimates can be partitioned into two components: (1) due to sample size, and (2) due to evolutionary variance (i.e., genetic drift). A chi-square test used to detect heterogeneity of admixture estimates from different alleles, or loci, can now be corrected for both sources of random errors. Hence, its value for the detection of natural selection from heterogeneous admixture estimates is improved. The estimation and testing procedures described above are independent of the dynamics of the admixture process. However, when the admixture dynamics can be specified, FST can be predicted from genetic principles. Two admixture models are considered here, gene flow and intermixture. These models are of value because they lead to very different predictions regarding the accumulation of genes from the parental populations and the accumulation of variance due to genetic drift. When there is not evidence for natural selection, and it is appropriate to apply these models to data, the variance effective size (Ne) of the hybrid population can be estimated. Applications are made to three human populations: two of these are Afro-American populations and one is a Yanomamö Indian village. Natural selection could not be detected using the chi-square test in any of these populations. However, estimates of effective population sizes do lead to a richer description of the genetic structure of these populations.

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