Validity of human races

The validity of human races is a subject of much debate. Many anthropologists, drawing on biological research, think common definitions of human races are without taxonomic validity. They argue that race definitions are imprecise, arbitrary, derived from custom, and vary across cultures. Others, however, argue that race continues to serve as a valid concept, and argue that movements to discredit racial classifications are often politically rather than scientifically motivated.

Human variation can be used to distinguish and classify humans into groups. Group admixture can hinder such analysis. The relationship between social and genetic definitions of race is complex. Phenotypic and genotypic classifications do not always correspond exactly. Common race definitions correspond to genotypic groupings insomuch as they correspond to ancestry. Whether human population structure warrants racial groupings is a matter of debate, with majority opinions varying between disciplines. Some biologists prefer the term population to race. Similar reasoning has led some to describe races as (inbred) extended families.

Contents

1 History of challenges to racial validity 2 Arguments against racial validity 2.1 Genetic variation 2.2 Race as a social construct and populationism 3 Arguments for racial validity 3.1 Genetic definitions of race 4 Footnotes 5 References

History of challenges to racial validity

In the early-to-mid 20th century, many scientists questioned previously accepted biological explanations of cultural attributes. Some questioned the taxonomic validity of human races, especially in the decades following the Second World War. This questioning gained momentum in the 1960s during the U.S. civil rights movement and the emergence of numerous anti-colonial movements worldwide. As data emerged in the 1960s showing most human genetic variation to be within races, not between them, many rejected human races as biological fact. Nevertheless, the belief that human races exist remains almost universal amongst lay audiences and, like any widely held belief, is significant regardless of its scientific validity.

In the 19th century many natural scientists made three claims about race: first, that races are objective, naturally occurring things; second, that there is a strong relationship between biological races and other human phenomena (such as social behavior and culture, and by extension the relative material success of cultures); third, that race is therefore a valid scientific category that can be used to explain and predict individual and group behavior. In the 20th century, mainstream anthropologists and others rejected each of these claims, while continuing to study between-group genotypic and phenotypic variations. By the end of the 20th century, most social and many natural scientists turned to the "population" concept to talk about these variations, arguing that accounts of "race" (within both the popular and scientific literatures) are socially constructed. Some social and natural scientists, however, argue that new studies in molecular genetics support a nomenclature strongly reminiscent of traditional racial and ethnic terminology.

A rejection of 19th century assumptions was initiated by Franz Boas, the founder of American academic anthropology. In the first decades of the 20th century he studied the relationship between race and height in New York City, discovering that the children of immigrants were taller than their parents. Although height is clearly primarily a biological phenomenon, he concluded that an individual's height was determined not only by inheritance but by environment as well (in this case, better pre- and neo-natal care, especially nutrition). Boas's conclusion has been confirmed many times since, for example by the remarkable gain in the average height of Japanese people since the dietary changes that followed the end of World War II. But it was counter-intuitive, because in typical populations under relatively stable environmental conditions, about 80% of the variation in individual height is due to genetic variations, and at any point in time, human subgroups tend to have different average heights. As a result, many of Boas's students continued to accept the existence of race as a biological fact. But they concluded that there was no relationship between biological race and other human phenomena (such as social behavior, culture, intelligence and morality)¹.

By the 1950s many anthropologists had come to question the very existence of race as a biological phenomenon.

Arguments against racial validity

Modern supporters of racial invalidity note that the preponderance of evidence suggests that all human beings are descended from a common ancestor. Second, they observe that there are many biological differences between people that are not taken into account by race (for example, blood type). Finally, they point out that oftentimes the genetic differences between members of the same race are greater than the average genetic difference between races. For example, the variation in blood types within specific groups is 85%, but the total variation between groups is only 15% (see the American Anthropological Association's Statement on Race [1]).

Genetic variation

Some scientists have argued there exists more variation within racial groups than between, and therefore human races have no taxonomic value. This opinion can be traced back to a 1972 paper by Richard Lewontin. Some researchers report the variation between racial groups (measured by Sewall Wright's population structure statistic F_ST) accounts for as little as 5-7% of human genetic variation.² This argument was widely popularized after Lewontin's original publication. However, most geneticists now recognize that low F_ST values do not invalidate the suggestion that there might be different human races because of technical limitations of F_ST and the observation that genetic variation between races is highly structured (Edwards, 2003; Risch, 2002). Thus, when one considers many points (i.e., genetic loci) of variation one can distinguish groups and allocate people into groups. The rules of biological classification do not set any 'smallest allowable difference' between taxa: any distinct difference is sufficient.

Opponents of racial groupings argue that a distinct difference is only one of the two conditions for racial classifiction; the second condition is a lack of significant gene flow between populations. Cultural anthropologists believe humans to be monotypic because they argue races gradually fade into one another in many parts of the world. Although there has historically been little or no gene flow between some human populations such as the aboriginal Australians and black Africans, they argue, one cannot assume there has been little interracial gene flow, as the interbreeding of locally adjacent populations might also produce it. Some researchers report enough such gene flow has occurred that the most recent common ancestor of all humans alive today has been estimated as living as recently as 3,500 years ago [2], although critics say this is not necessarily significant gene flow (Rhode et al., 2004). Intercontinental travel has caused increased gene flow between geographically distant human populations. In some regions, this has caused racial lines to fade or perhaps disappear, particularly Latin American and parts of Southern Africa.

The delicacy of this definition has left the issue much in debate, especially among physical anthropologists, for if clines lead to large areas of near-homogeneity, such as Kenya, Sweden and China, then the people in these areas seem marked off by delimiters resembling nothing so much as the traditional physiological touchstones of "race". However, a recent report argues there is evidence for smooth, clinal genetic variation even in such regions, with the apparent gaps turning out to be artifacts of sampling techniques (Serre & Pääbo, 2004). Currently, the question of whether human genetic variation is better described as clinal (i.e. no races) or cladistic (i.e. races are real) is largely unresolved.

The problem arises of distinguishing black Africans as a racial group; it doesn't work because it is a paraphyletic classification. In other words, under a phylogenetic classification, considering black Africans as a single racial group would require one to include every living person on Earth within that single African "race", because the genetic variation of the rest of the world represents essentially a single subtree within that of Africa. Also, it has long been known that groups such as the Khoisan were as different from other sub-Saharan groups as are Europeans and Asians (though even with the Khoisan the distinction is no longer so clearcut, as a large amount of intermarriage with both Europeans and Bantu-language speakers has occurred over the last three centuries).

Race as a social construct and populationism

Historians, anthropologists and social scientists often describe human races as a social construct, preferring instead the term population, which can be given a clear operational definition. Even those who reject the formal concept of race, however, still use the word race in day-to-day speech. This may either be a matter of semantics, or an effect of an underlying cultural significance of race in racist societies. Regardless of the name, a working concept of sub-species grouping can be useful, because in the absence of cheap and widespread genetic tests, various race-linked gene mutations (see Cystic fibrosis, Lactose intolerance, Tay-Sachs Disease and Sickle cell anemia) are difficult to address without recourse to a category between "individual" and "species". As genetic tests for such conditions become cheaper, and as detailed haplotype maps and SNP databases become available, the need to resort to race should diminish. This is fortunate, as recent interracial mating is reducing the predictive power of race. For example, most babies born with Tay-Sachs in North America at present are not from Jewish families, despite stereotypes to contrary.

In everyday speech, race often describes populations better defined as ethnic groups, often leading to discrepancies between scientific views on race and popular usage of the term. For instance in many parts of the United States, categories such as Hispanic or Latino are viewed to constitute a race, though others see Hispanic as a linguistic and cultural grouping coming from a variety of backgrounds. In the United States, in what is referred to as the one-drop rule, the term Black subsumes people with a broad range of ancestries under one label, even though many who are termed Black would be more accurately described as White under any objective terminology. In much of Europe groups such as Roma, Turks, and Arabs are commonly defined as racially distinct from White Europeans, though all of these groups are considered to be "Caucasian" in traditional physical anthropology.

Some argue it is preferable when considering biological relations to think in terms of populations, and when considering cultural relations to think in terms of ethnicity, rather than of race. Instead of classing people into one "group", say "Caucasians" or Europeans you have Britons, Frenchmen, Germans, Nords, western Slavs and Celts rather than having a term implying a ("possible") ancestor group in the Caucasus that is too distant for consideration and moreover reaching to groups including eastern Slavs, Roma, Persians and Indians, and others that differ notably, both culturally and to a lesser yet still noteworthy extent physically, from the aforementioned ethnic groups There can be as much difference between two ethnicities grouped into a "race" as between either of those and an ethnic group grouped (often arbitrarily) into another "race".

These developments had important consequences. For example, some scientists developed the notion of "population" to take the place of race. This substitution is not simply a matter of exchanging one word for another. Populations are, in a sense, simply statistical clusters that emerge from the choice of variables of interest; there is no preferred set of variables.

The "populationist" view does not deny that there are physical differences among peoples; it simply claims that the historical conceptions of "race" are not particularly useful in accounting for these differences scientifically. In particular, populationists claim that:

1. knowing someone's "race" does not provide comprehensive predictive information about biological characteristics, and only absoltuely predicts those traits that have been selected to define the racial categories, e.g. knowing a person's skin color, which is generally acknowledged to be one of the markers of race (or taken as a defining characteristic of race), does not allow good predictions of a person's blood type to be made;
2. in general, the world-wide distribution of human phenotypes exhibits gradual trends of difference across geographic zones, not the categorical differences of race; in particular, there are many peoples (like the San of S. W. Africa, or the people of northern India) who have phenotypes that do not neatly fit into the standard race categories.
3. focusing on race has historically led not only to seemingly insoluble disputes about classification (e.g. are the Japanese a distinct race, a mixture of races, or part of the East Asian race? and what about the Ainu?) but has also exposed disagreement about the criteria for making decisions— the selection of phenotypic traits seemed arbitrary.

Since the 1960s, some anthropologists and teachers of anthropology have re-conceived "race" as a cultural category or social construct, in other words, as a particular way that some people have of talking about themselves and others. As such it cannot be a useful analytical concept; rather, the use of the term "race" itself must be analyzed. Moreover, they argue that biology will not explain why or how people use the idea of race: history and social relationships will.

Arguments for racial validity

Some biologists believe that the view that races are a social construct or not biologically significant is incorrect. They point to the existence of groups determined on the basis of multi-locus genetic analysis as evidence that human population structure does exist and to some extent is resembles conventional definitions of race. In most contemporary research, races are defined as evolutionary linages: "a subspecies (race) is a distinct evolutionary lineage within a species. This definition requires that a subspecies be genetically differentiated due to barriers to genetic exchange that have persisted for long periods of time; that is, the subspecies must have historical continuity in addition to current genetic differentiation" Templeton (1998).

Some researchers believe the view that races do not exist is influenced by racial politics and political correctness, not science. They claim that race researchers are often attacked as racists, even if they espouse liberal sociopolitical views and claim to be against racism. Vincent Sarich and Frank Miele , in Race: The Reality of Human Differences, write that "racial differences in humans exceed the differences that separate subspecies or even species in such other primates as gorillas and chimpanzees" and that "race is a biologically real phenomenon with important consequences". A number of scientists have supported this currently controversial view, including Ralph L. Holloway , Professor of Anthropology, Columbia University; Arthur Jensen; Joseph Carroll , University of Missouri-St. Louis; and Thomas J. Bouchard, Jr. , Prof. of Psychology, University of Minnesota.

An amount of change sufficient to label two different animal populations as different sub-species is often not considered enough to label two different human populations as being of different races. (Ref?)

Other anthropologists and human geneticists argue that race is indeed a valid and valuable concept and that those holding the opposite view allow their social consciences (laudable per se) to confuse and delay accurate interpretations and applications of empirical data. They are not convinced by the substitution of the term "population" for the term "race" because it leads to a potentially harmful imprecision in communication (for example, when one could simply say "Caucasian" one is instead compelled to say something like "an individual of the western Eurasian population", and when that individual doesn't happen to currently reside in western Eurasia one must say "an individual whose ancestors were of the western Eurasian population"). This position recently received a boost from genetic studies at the molecular level which show characteristic allele signatures for the groups traditionally identified as the three major races, resulting in maps that clearly delineate genetic clines (in which the clinal zones are a small part of the total). The basal groups outside the clinal zones on these maps are summarized quite well by longstanding racial and ethnic appellations. Recognition of these groups, and simple ways to refer to them, is especially important in fields like medical research and diagnosis because a rapidly growing list of genetic disorders and predispositions are strongly linked to race and ethnicity (not to geographical "populations"). If "races" is too freighted a term for these basic divisions of humanity then, according to these authorities, new, convenient, non-academic terminology free of spurious valuations of superiority and inferiority should be developed and deployed whether social sensitivities are ruffled or not.

Genetic definitions of race

Some scientists argue that in determining overall relatedness the entire genetic cohorts of groups must be compared, and that when this is done, one can recover the traditional racial groupings, provided one uses enough of the right markers. However, one must decide how finely one chooses to distinguish between groups, such that one can determine two races (Africans vs. non-Africans), three, four or more. Thus, the number of races discovered by these methods will be arbitrary. Also, some of the groups which emerge as "races" under closer scrutiny would hardly be recognized as such in the conventional sense.

The geneticist A.W.F. Edwards argued in 2003 that race exists. He points out that most of the information that distinguishes populations is not simply the sum of variation of individual genes (the 6 percent), but is variation hidden in the correlation structure of the data. The argument is technical and difficult to follow for those with no statistical training, but is presented in detail in the paper by Edwards (the journal BioEssays volume 25 pages 798-801). It was this argument of Edwards that finally convinced Richard Dawkins, Professor of Public Understanding of Science at Oxford University, UK (the author of The Selfish Gene) in his new 2004 book The Ancestor's Tale, that race in mankind is of taxonomic value, in other words, races do exist, despite the fact that the boundaries between races are blurred.

Footnotes

1. For further information on Boas's own understanding of race, see his speech "Race and Progress", Science 74, no. 1905 (1931): 1–8, an external link to which appears below.
2. Note that the set of integers from 1 to 10 varies more widely within the set than it differs from the set of integers from 2 to 11.

References

• Boas, Franz (1931). Race and Progress. Science 74, 1–8 [3]
• Edwards, AW (2003). Human genetic diversity: Lewontin's fallacy Bioessays 25, 798–801. [4]
• Lewontin, Richard C. (1972). The apportionment of human diversity. In Dobzhansky T, Hecht MK, Steere WC (Eds.), Evolutionary Biology 6, p 381–398. New York: Appleton-Century-Crofts.
• Risch, N.; Burchard, E.; Ziv, E. & Tang, H. (2002). Categorization of humans in biomedical research: genes, race and disease. Genome Biol. 3, comment2007. [5]
• Rhode, Douglas L. T.; Olson, Steve E.; Chang, Joseph T. (2004). Modelling the recent common ancestry of all living humans. Nature 431, 562–566. [6]
• Sarich, Vincent; Miele, Frank (2004). Race: The Reality of Human Differences, Westview Press.
• Serre, David; Pääbo, Svante (2004). Evidence for Gradients of Human Genetic Diversity Within and Among Continents. Genome Research 14, 1679–1685. [7]