Multilocus Genetic Analysis and the Assessment of Human Ancestry

Article excerpt

Social scientists almost universally subscribe to the notion that race is a social construct without a biological basis. In the second half of the twentieth century biological definitions of race were dismissed by professional groups as well as by a sizable portion of the general public. The shortage of convincing research evidence and a reaction to previous racist claims, with the accompanying history of inhumanity, resulted in the near absolute refusal to consider the possibility of a genetic provenance for race. Molecular genetic studies using analysis of multiple loci are reviewed, which identify clusters of genetic markers that consistently show an association with racial group membership. Applications of this research in the medical and forensic sciences are discussed, as well as implications for future investigations.

Key Words: DNA; Polymorphisms; Race; Human populations; Genotyping; Multilocus analysis

The subject of race can be a minefield of sensitivities, subtleties and miscommunication. Opinions and hypotheses about the nature and features of race quickly can be misinterpreted as an attack that must be defended. Yet, as Thomas Jefferson (1801) observed, "Every difference of opinion is not a difference of principle." Belief in the inherent dignity of all human life need not be set in opposition to the scientific examination of the variations of that life. Our human family, intrinsically bound together by history and biology, is a legitimate subject of scientific inquiry. The nature of that inquiry changes as new tools for scientific research emerge from advancements in research technology. The Human Genome Project, which mapped human DNA, offers new methodologies to answer old questions regarding the contributions of genetics to the understanding of human ancestry.

Human society has had a pathological relationship with the issue of race. Race pervades a great deal of the social and interpersonal issues with which we must contend, yet we have no effective way of talking about it. To raise the subject in discussion is to raise the emotional tenor of a conversation, which leads to stereotypic assumptions and loss of communication. Although it is a topic that we desperately need to address, we do not seem to have even a common language to talk about it.

Some deny the existence of race. At other times, these same people may laud the achievements of their race. Some schools admit students without regard to race. Some schools have admission policies to guarantee racial representation, and other schools were founded on the principle of lifting up their race. Laws are passed to prevent discrimination based upon race, and there are laws that discriminate against immigrant groups because of their race. It seems that no matter how we might try to circumvent the idea of race, people will continue to use it when it suits their interests. Having a comprehensive definition of race from both genetic and cultural perspectives may help to begin a less passionate discourse based upon scientifically derived definitions and generally accepted terms.

Recent research demonstrates that the human characteristic that we historically have referred to as race can be identified using sophisticated genetic analysis. Various researchers express the nature of this ancestry with such terms as: continental populations, points of geographic origin, gene pools, haplogroups and haploclusters. Undoubtedly, such investigations will cause concern among individuals and groups. One might ask why science studies the issue of race from a genetic perspective. A short answer is that medical conditions that have a genetic basis have stimulated much research in this area (e.g. Metcalfe, 2008; Fine, Ibrahim & Thomas, 2005). Clinical observations have demonstrated connections between ancestry and frequency of various diseases and responses to medical interventions. To develop a better understanding of the distribution of these apparent inherited predispositions researchers have turned to the study of genetic variations in human groups. …