Science Fair Project Encyclopedia
Contemporary views on race
Contemporary views on race vary considerably between and within academic disciplines. Contemporary views differ from historical ones. Many views are complex, and are distinguished by subtle differences. Often the significance of differences between views is related to the use of race in biomedicine. This article compares the major contemporary views on race.
Summary of contemporary views
Do human races exist?
- Racial realism
- Racial skepticism: race does not exist
What about subspecies?
- The terms 'race' and 'subspecies' are often used synonymously, some argue this is the correct definition (Kittles?).
- Typically, 'race' is used for humans and 'subspecies' for non-humans.
- When they are distinguished, 'race' is generally a lower level category than 'subspecies'.
If race had a biological basis, what would it be?
- Taxonomic: "An aggregate of phenotypically similar populations of a species, inhabiting a geographic subdivision of the range of a species, and differing taxonomically from other populations of the species." (Mayr, 1969)
- Population: "Races are genetically distinct Mendelian populations. They are neither individuals nor particular genotypes, they consist of individuals who differ genetically among themselves." (Dobzhansky, 1970)
- Lineage: "A [race] is a distinct evolutionary lineage within a species. This definition requires that a [race] be genetically differentiated due to barriers to genetic exchange that have persisted for long periods of time; that is, the [race] must have historical continuity in addition to current genetic differentiation." (Templeton, 1998)
The phylogeographic subspecies definition
A phylogeographic criteria for 'subspecies' was established in the early 1990s (Avise and Ball, 1990; O’Brien and Mayr, 1991).
- "members of a subspecies would share a unique, geographic locale, a set of phylogenetically concordant phenotypic characters, and a unique natural history relative to other subdivisions of the species. Although subspecies are not reproductively isolated, they will normally be allopatric and exhibit recognizable phylogenetic partitioning. ... evidence for phylogenetic distinction must normally come from the concordant distributions of multiple, independent genetically based traits." (Miththapala et al., 1996)
Total human genetic diversity
It is widely claimed that human genetic diversity is smaller than that of other mammals.
Time frame of modern human evolution
Mitochondrial DNA from contemporary humans coalescences to a common ancestor living 150,000 years ago (see Mitochondrial Eve). However, nuclear DNA loci have a range of coalescence times, some predating the origin of modern humans or even hominids.
Distribution of genetic variation within/between populations
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 FST) accounts for as little as 5-7% of human genetic variation. This argument was widely popularized after Lewontin's original publication.
However, most geneticists now recognize that low FST values do not invalidate the suggestion that there might be different human races because of technical limitations of FST (Edwards, 2003).
Populations within continents are more closely related to one another than to populations on other continents. Genetic variation between races is highly structured (Risch, 2002). Thus, when one considers many points (i.e., genetic loci) of variation one can distinguish groups and allocate people into groups (Bamshad, 2004).
Which populations qualify as races?
Opinions vary. Cavalli-Sforza seems to ennumerate four major populations which would be called races: "Africans," "Caucasoids," "Mongoloids," and "Australian Aborigines." Others ennumerate five races: Sub-Saharan Africans , Caucasians, East Asians, Australopapuans and Amerindians.
Do self-identified races have biological validity?
Opinions vary. Recent research indicates that self-described race is a near-perfect indicator of an individual's genetic profile, at least in the United States. Using 326 genetic markers, Tang et al. (2005) identified 4 genetic clusters among 3,636 individuals sampled from 15 locations in the United States, and were able to correctly assign individuals to groups that correspond with their self-described race (white, African American, East Asian, or Hispanic) for all but 5 individuals (an error rate of 0.14%). They conclude that ancient ancestry, which correlates tightly with self-described race, and not current residence, is the major determinant of genetic structure in the US population.
Are self-identified races merely populations?
What are the implications of the clinal view of human variation?
What does admixture mean for the biological validity of races?
What is the relationship between race and ethnicity?
- Dobzhansky, T. (1970). Genetics of the Evolutionary Process. New York, NY: Columbia University Press.
- Mayr, E. (1969). Principles of Systematic Zoology. New York, NY: McGraw-Hill.
- Templeton, A.R. (1998). Human races: A genetic and evolutionary perspective. Am. Anthropol. 100, 632–650.
- Avise, J.C., Ball, R.M. 1990. Principles of genealogical concordance in species concepts and biological taxonomy. Oxford Surveys in Evolutionary Biology 7:45-67.
- O’Brien, S.J., Mayr, E. 1991. Bureaucratic Mischief: Recognizing Endangered Species and Subspecies. Science. 2 51:1187-1188.
- Miththapala, S., Seidensticker, J., O’Brien, S.J. 1996. Phylogeographic Subspecies Recognition in Leopards (Panthera pardus): Molecular Genetic Variation. Conservation Biology 10:1115-1132.
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