I was flipping through a science magazine in the school library and I came across an article that details an extensive research which proves that race does not exist. I mean this is something I've always believed and all I needed was a scientific back-up, here it is.
Excerpts:
Look around on the streets of any major city, and you will see a sampling of the outward variety of humanity: skin tones ranging from milk-white to dark brown; hair textures running the gamut from fine and stick-straight to thick and wiry. People often use physical characteristics such as these--along with area of geographic origin and shared culture--to group themselves and others into "races." But how valid is the concept of race from a biological standpoint? Do physical features reliably say anything informative about a person's genetic makeup beyond indicating that the individual has genes for blue eyes or curly hair?
The problem is hard in part because the implicit definition of what makes a person a member of a particular race differs from region to region across the globe. Someone classified as "black" in the U.S., for instance, might be considered "white" in Brazil and "colored" (a category distinguished from both "black" and "white") in South Africa.
Yet common definitions of race do sometimes work well to divide groups according to genetically determined propensities for certain diseases. Sickle cell disease is usually found among people of largely African or Mediterranean descent, for instance, whereas cystic fibrosis is far more common among those of European ancestry. In addition, although the results have been controversial, a handful of studies have suggested that African-Americans are more likely to respond poorly to some drugs for cardiac disease than are members of other groups.
Given that people can be sorted broadly into groups using genetic data, do common notions of race correspond to underlying genetic differences among populations? In some cases they do, but often they do not. For instance, skin color or facial features--traits influenced by natural selection--are routinely used to divide people into races. But groups with similar physical characteristics as a result of selection can be quite different genetically. Individuals from sub-Saharan Africa and Australian Aborigines might have similar skin pigmentation (because of adapting to strong sun), but genetically they are quite dissimilar.
In contrast, two groups that are genetically similar to each other might be exposed to different selective forces. In this case, natural selection can exaggerate some of the differences between groups, making them appear more dissimilar on the surface than they are underneath. Because traits such as skin color have been strongly affected by natural selection, they do not necessarily reflect the population processes that have shaped the distribution of neutral polymorphisms such as Alus or short tandem repeats. Therefore, traits or polymorphisms affected by natural selection may be poor predictors of group membership and may imply genetic relatedness where, in fact, little exists.
Another example of how difficult it is to categorize people involves populations in the U.S. Most people who describe themselves as African-American have relatively recent ancestors from West Africa, and West Africans generally have polymorphism frequencies that can be distinguished from those of Europeans, Asians and Native Americans. The fraction of gene variations that African-Americans share with West Africans, however, is far from uniform, because over the centuries African-Americans have mixed extensively with groups originating from elsewhere in Africa and beyond.
Over the past several years, Mark D. Shriver of Pennsylvania State University and Rick A. Kittles of Howard University have defined a set of polymorphisms that they have used to estimate the fraction of a person's genes originating from each continental region. They found that the West African contribution to the genes of individual African-Americans averages about 80 percent, although it ranges from 20 to 100 percent. Mixing of groups is also apparent in many individuals who believe they have only European ancestors. According to Shriver's analyses, approximately 30 percent of Americans who consider themselves "white" have less than 90 percent European ancestry. Thus, self-reported ancestry is not necessarily a good predictor of the genetic composition of a large number of Americans. Accordingly, common notions of race do not always reflect a person's genetic background.
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