Race: an anthropological perspective
Alice Brues defined race as "a division of a species which differs from other divisions by the frequency with which certain hereditary traits appear among its members." This definition of race, like most others, is rather equivocal, in that it does not tell us how much variance in the frequency of traits necessitates the creation of a new race. If we take this definition at face value then according to craniometric and genetic data an incalculable number of races exist.
In 1972, R.C. Lewontin reported that, for genes at a single locus, most genetic variation existed within populations, rather than between them. For most biologists this put the nail in the coffin for the race concept. In a re-examination of Lewontin's findings, the Cambridge statistician A.W.F. Edwards, noted that our ability to correctly classify populations is due to the correlations among different loci. By focusing on multiple loci the between population differences increase dramatically.
As way of an analogy, imagine we asked a stranger the following question via internet: "Which colour do you prefer less: orange or brown?" Previous surveys have showed that there is a slightly greater tendency for women to rate orange as their least favourite colour, while men have a slightly greater tendency to dislike brown. However, there is a very high amount of overlap. We would have a tough time trying to predict sex based on the results of this single question. However, if we ask say thirty questions instead of one, we would be able to predict sex with a much higher degree of certainty based on the responses as a whole. In a similar manner, we could not confidently determine race of an individual based on one or two cranial measurements. However, the likelihood of a positive determination increases significantly when we include more measurements.
Craniometrics has been shown to correctly classify individuals into a few broadly defined racial categories, as well as many more geographically localised categories. The ability of forensic anthropologists to accurately classify individuals into predefined groups does not substantiate the biological race concept. Just because we can determine a skeleton to be of Irish, Western European, Northwestern European or European ancestry does not mean that such ancestral groups exist in any meaningful biological sense. However, such information is useful for homicide investigators who are interested in whittling down their list of possible missing persons.
So how are we to understand race? Human variation is probably best understood in terms of both temporal and geographic distances. Cranial variation correlates strongly with geography; meaning that the further apart the populations are geographically, the more dissimilar they are phenotypically. Conversely, neighbouring populations show greater phenotypic similarities, spurring anthropologist Frank Livingstone to write in 1962 "there are no races, only clines”. The relationship between phenotypic variation and geography is likely due to both isolation by distance (there is greater gene flow between neighbouring populations) and the many founder effects that occurred in the course of human history. The longer groups remain isolated the more dissimilar their genotypes. Since most racial categories are defined by geographic regions, it should not come as a surprise that there is a correlation between race and place of ancestry.
Race is a crude sociocultural construct based on the underlying reality of biological variation. In this regard it is similar to other cultural phenomena, which help us understand our past. For example, much can be ascertained about ancestry and human migration by studying languages. In this regard, race has proved to be a useful concept in the fields of medicine and law enforcement. As long as law enforcement continue to use racially defined categories, forensic anthropologists will similarly follow suit.
Above photo modified from original by indianfilipino under creative commons license.