The ability to sequence an entire human genome has ushered in a whole new era of scientific study. Along with this ability has come the realization of the incredible genetic similarity between humankind as a whole, juxtaposed by the minute differences that cause the uniqueness of each individual. Intrigued by the genetic similarities and differences among peoples, some researchers have looked to see if these similarities and differences could be grouped and in what ways. One such study was conducted by a team of scientists led by N.A. Rosenberg in which they concluded that genetically, people seem to fall consistently into six groups that correspond to certain geographic areas. While this study is fairly thorough and lacks obvious bias, the inaccessibility of this specialized scientific knowledge allows for the data to be easily misconstrued within society. The scientific data and the social misconstructions that stems from this data are inevitably intertwined, illuminating the need for interdisciplinary mediation and understanding.
In 2002 a team of population geneticists headed by Noah Rosenberg performed a study, “Genetic Structure of Human Populations”, looking at genetic similarities between the genomes of 1056 individuals from 52 populations. By viewing the same specific locations of each individual’s genome, the team could then compare similarities and differences between them. They then used a computer program called STRUCTURE, which analyzed this data and
allotted individuals into pre-assigned groups based on their similarities. For example, STRUCTURE could be set to specify two groups among these individuals and would then place individuals into these groups based on percentage of similarity to each other. Rosenberg et al. found that 6 was the optimal number of clusters, or groups, that individuals naturally fell into. That is, STRUCTURE found that individuals could be placed into groups with a much nearer to 100 percent similarity to each other when they were assigned into six groups than when any other number of groups were specified. The team found that the individuals comprising these six groups were also mostly found to be from similar geographic regions. Thus, they concluded that people from the same geographic area are more genetically similar to one another.
Science is not infallible; it is undeniably a field of study that makes mistakes and is constantly evolving. There are also scientific studies that are done well and ones that are not. The study we are examining, “Clines, Clusters, and the Effect of Study Design on the Inference of Human Population Structure” by Rosenberg et. al., is science done well, taking as many variables into account as possible as well as being self critical of their own methodology. After their first study, many critiques were made concerning the study design of Rosenberg et al.’s research. Serre and Paabo posed one specific critique of the study. They posed that the geographic dispersion of the sample inherently led to increased clusteredness. In response to these critiques, Rosenberg et al. re-conducted their study in 2005, and looked at the effect different aspects of their study design had on their results. The study design variables, such as sample size or the geographic dispersion of samples, were analyzed one by one, holding all other variables constant in order to determine a fair assessment of the effects of each. The team found their results to be “robust” to any study design techniques. Even taking into account suggested method biases; the data still seemed to point to six genetic clusters as the best fit for grouping genetic similarities.
Yet there are a couple of outstanding issues with this data and its findings. One is the number of subjects and the geographic dispersion these samples come from. Scientifically speaking 1056 subjects is quite extensive, but ultimately, in order to fully support the broad claims this study makes about people and their genetic similarities, many more samples should be used. We understand that sequencing the human genome for almost the entire world is highly unlikely and the processing of that amount of data could take decades, but the optimal support for the claims being made would be a larger, more uniformly distributed, sample size that Rosenberg and his don’t have.
Also, there is a lack of statistical support. While Rosenberg et al. used clusteredness to analyze the probability of individuals falling into pre-assigned groups, there was limited analysis done on the probability of observing this data given different values of K. At the time this study was conducted, the program STRUCTURE did not have a statistical technique that would analyze the highest likelihood of the number of clusters. For example, this new technique would be able to statistically identify if six was the optimal number of clusters for this data, based on the likelihood of observation given K. Scientists have yet to run this statistical analysis of Rosenberg et al.’s STRUCTURE results. In Rosenberg et al.’s initial study, they performed runs with STRUCTURE using values of K ranging up to 20. Having never performed the newly created statistical analysis on the likelihood of the clusters, then the question still remains, what is the justification for positing that 6 is the “best representation of human genetic variation”.
While the results of this study do not provide a genetic basis for race, the data has in many instances been taken as proof of genetic, or inherent, differences between races. The fact that there appears to be some kind of connection between geographic origin and allele frequency lead many to jump to the conclusions. It is true that people who have lived in the same geographic region for many generations may have some genetic similarities (due to adaptations to environment, mating, and other factors), but there is no genetic material that is found in all members of one population and no members of others. The main trouble with saying that these differences in allele frequencies are race based is that this gives people a way to try to attach complex environmentally and socially determined behaviors, like “propensity to violence” and intelligence, to genetic variation.
In the medical field, the use of genetics can promote the resurgence of a very essentialist form of thinking. Troy Duster, Professor of Sociology and Director of the Institute for the History of the Production of Knowledge at New York University, draws connections between this surge of essentialist thinking and the new biotechnologies that tend to show greater frequency of genetic deficiencies among “at risk populations”, which typically correspond to specific ethnic groups. He warns against the risks of stigmatization, discrimination, and marginalization of groups in a society where power is not evenly distributed. Some time in the near future, he believes various institutions could determine access to education, employment and insurance using genetic screening tests. Duster believes that these individuals could become “biological pariahs” deemed “unfit” due to their biological status. Advances in the human genome and the understanding of human differences, through such studies as the one presented, have the ability to“prove to be empowering, or it could simply add to the legacy of hatred, alienation, and distrust”.
We have seen in the past how science has claimed to have found racial difference, and associated value with those differences, in examples like Morton’s skull measuring or in IQ testing, so to find an acclaimed genetic difference amongst races would certainly prove disastrous for generations of advocates of human equality. Yet, this study never claimed to have found racial differences among populations. Through understanding that what society thinks about this study and what it actually claims to have found, we see that Duster’s rejection of the validity of ancestry and its relationship to race its completely applicable. What Duster does not address is that the study done by Rosenberg et. al. does not claim to have ever determined genetic racial difference. It claims to have found 6 specific populations that generally coincide with major geographic locations. The genetic similarities among the populations and the differences between the populations demonstrate that around the world there is genetic variation.
When first looking over this study, it was clear that this article was not written for the general public. When reading this article you need to have an advanced knowledge of the subject matter to comprehend what is being said. As we mentioned above, it would be very easy to misunderstand and/or misinterpret the contexts when being read by an average person with no complex knowledge of human genetics.Although the article was made available to the public its findings are still unclear to most who read it. This lack of explanation is one of the main
problems with human genetic studies and their findings. At the end of the study Rosenberg et. al state that “the arguments about the existence or non-existence of “biological races” in the absence of a specific context are largely orthogonal to the question of scientific utility, and they should not obscure the fact that, ultimately, the primary goals for studies of genetic variation in humans are to make inferences about human evolutionary history, human biology, and the genetic causes of disease.” They place this at the very end of the article as a disclaimer of their social agenda; how they are not trying to scientifically claim race. This one sentence, social explanation at the end of the study is not enough to clarify in the publics mind the true results of the study. The fact that this sentence was even included means that the scientists realized that the results of this study could be misconstrued; yet no further explanation is given as to what the results of their study really mean and its possible implications.
Troy Duster also has much to say about this study and its faults. In a presentation given as UCSB, Duster concludes his lecture with the statement “the claims that are being made in sober circumstances, on PBS, about ancestry, have no valid basis”. The presentation that Duster gave and the conclusions he came to were in direct reference to this study done by Rosenberg et. al. From a sociological perspective, the concerns that Duster has with this study are valid; however, in his interpretation of the studies’ results seems to illuminate his sociological perspectives overshadowing the scientific data and its intended results. We have indicated that those not privy to the specialized knowledge and research it is investigating have misinterpreted this study as a validation for “race”. Troy Duster certainly realizes, and is speaking to, the impact of this interpretation among the general public. Making the argument for and claiming to have scientifically proved genetic racial difference would have numerous effects on society.
The science world cannot be divorced from the social world. It is absolutely impossible for scientists to separate their studies from individual and societal worldviews. When considering why this study was even done by the U.S. born Rosenberg it is difficult to believe that an interest in race and American society was nonexistent. Even in something as simple as allowing study participants to self- identify native ancestry disintegrates the notions of a completely objective study from the very beginning. To present scientific information that is as important and controversial as the Rosenberg study without significant mentions of the social implications of said study is irresponsible. The voice of the scientific community is exceedingly necessary for proper interpretation of presented material. Their expertise is invaluable. Data means little without interpretation. On the flipside, sociologists need to respect the work of scientists and the society at large need to take the time to attempt to understand the meaning
and validity of these scientific findings. Although historically there have been reasons for distrust of science, sociologists need not assume that science actively seeks to create or maintain racial hierarchy. In science there is truth and means for understanding our world. The scientific community and the social science community need to work together to make their work accessible and understandable for each other as well as the general public. Proper analysis of the complex ways in which society and genetics interact requires interdisciplinary discussion, open-mindedness, and most importantly the building of bridges that will allow all to cross into a place of understanding.
Tidak ada komentar:
Posting Komentar