Cavalli-Sforzas map of genetic diversity This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. This applies worldwide. Map on book jacket of Luigi Luca Cavalli-Sforzas The History and Geography of Human Genes...

Cavalli-Sforzas map of genetic diversity This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. This applies worldwide. Map on book jacket of Luigi Luca Cavalli-Sforzas The History and Geography of Human Genes...

Map of human genetic diversity, from the dust jacket of The History and Geography of Human Genes, (Cavalli-Sforza 1994) "The color map of the world shows very distinctly the differences that we know exist among the continents: Africans (yellow), Caucasoids (green), Mongoloids ... (purple), and Australian Aborigines (red). The map does not show well the strong Caucasoid component in northern Africa, but it does show the unity of the other Caucasoids from Europe, and in West, South, and much of Central Asia."

Contemporary views on This article is about race as an intraspecies classification. For the many types of competitive sport, see Racing. For racing conditions associated with computer programming, see Race hazard. A race is a distinct population of humans distinguished in some way from other humans. The most widely observed races are those... race vary considerably between and within academic disciplines. Contemporary views differ from Map of skin-color distribution for native populations collected by Renato Biasutti prior to 1940. The pigmentation is graded in the von Luschan scale. The definition of race, before the development of evolutionary biology, was that of common lineage—a vague concept interchangeable with species, breed, cultural origin, or... 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 refers to an active debate among biomedical researchers about the meaning and importance of race to their research. Several questions are being considered: When should race be taken into account when studying humans? What definition of race is appropriate for biomedical research? Do the biological differences between... race in biomedicine. This article compares the major contemporary views on race.

Summary of contemporary views

Do human races exist?

• Racial realism
  • Racial naturalism: races are important biological or In philosophy a natural kind is a family of entities possessing properties bound by natural law; we know of natural kinds in the form of categories of minerals, plants, or animals, and we know that different human cultures classify natural realities that surround them in a completely analogous fashion (Molino... natural kinds
  • Racial constructionism: races are not biological kinds, but they are Social scientists and literary scholars have claimed that many things are social constructions or social constructs, or that they have been socially constructed. Contents // 1 The term social construction 2 What entails a social construct? 2.1 Weak social constructionism 2.2 Strong social constructionism 3 What kind of analyses... social constructs
• 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?

• Taxonomy (from Greek ταξινομία from the words taxis = order and nomos = law) may refer to either a hierarchical classification of things, or the principles underlying the classification. Almost anything, animate objects, inanimate objects, places, and events, may be classified according to some... 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 genetics is the study of the distribution of and change in allele frequencies under the influence of the four evolutionary forces: natural selection, genetic drift, mutation and migration. It also takes account of population subdivision and population structure in space. As such, it is the theory that attempts to... 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)
• In population genetics, a cline is a gradual change of a character or feature (phenotype) in a species over a geographical area. The change in phenotype does not result in different species as long as the geographically spread populations can interbreed with one another. This meaning of cline was introduced... Clines:
• 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 Centuries: 19th century - 20th century - 21st century Decades: 1940s 1950s 1960s 1970s 1980s - 1990s - 2000s 2010s 2020s 2030s 2040s Years: 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Contents // 1 Events and trends 1.1 Computers, technology 1.2 Science 1.3 War, peace and politics 1.4... 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)

Background

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 An artists impression of Mitochondrial Eve who probably lived in Africa, about 150,000 years ago. A comparison of the mitochondrial DNA of humans from many races and regions suggests that all of these DNA sequences have evolved molecularly from a common ancestor sequence. Under the assumption that an... 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 Charles Lewontin (born March 29, 1929) is an evolutionary biologist, geneticist, and social commentator at Harvard University. A leader in developing the mathematical basis of population genetics and evolutionary theory, he pioneered the notion of using techniques from molecular biology such as gel electrophoresis to apply to questions of... Richard Lewontin. Some researchers report the variation between racial groups (measured by Sewall Green Wright (December 21, 1889 - March 3, 1988) was one of the primary founders of population genetics which led to the modern evolutionary synthesis. In a long career, he invented much of the theory of genetic drift (also known as the Sewall Wright effect) and developed the inbreeding coefficient... Sewall Wright's population structure statistic F_ST) 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 F_ST values do not invalidate the suggestion that there might be different human races because of technical limitations of F_ST (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., This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). Introns are regions often found in eukaryote genes which are removed in the splicing process: only the exons encode the protein. This diagram labels a region of only 40... genetic loci) of variation one can distinguish groups and allocate people into groups (Bamshad, 2004).

Topical comparisons

Which populations qualify as races?

Opinions vary. Cavalli-Sforza seems to ennumerate four major populations which would be called races: " World map showing location of Africa A satellite composite image of Africa Africa is the worlds second_largest continent in both area and population, after Asia. At c. 30,244,050 km2 (11,677,240 mi2) including its adjacent islands, it covers 20.3% of the total land area on... Africans," " Typical Caucasoid Skull Caucasoid describes the race of humans primarily from Europe, North Africa, the Middle East (western Asia) as well as parts of Central Asia and India, and was one of the four major races as recognized by nineteenth century racial theories. Also spoken of (in a more linguistical... Caucasoids," " The term Mongoloid describes a proposed race of humans, most of whom live in Asia and the Pacific Rim. The grouping was one of the four major races recognized by Nineteenth Century racial theories. Epicanthal folds and oblique palpable fissures are common among most Mongoloid individuals. Most exhibit Mongolian spot... Mongoloids," and " Australian Aborigines are the indigenous peoples of Australia. Their ancestors probably arrived in Australia just over 50,000 years ago, although the date remains in dispute. Aboriginal Flag Torres Strait Islander Flag Contents // 1 History 1.1 Pre-colonisation 1.2 British colonisation 1.3 The 20th century 1.4... Australian Aborigines." Others ennumerate five races: Sub-Saharan Africans, Caucasian is originally a geographical term, meaning relative or pertaining to the Caucasus region of eastern Europe. It has in time acquired other specific meanings: in linguistics, the Caucasian languages are a large number of languages spoken in the Caucasus area; often specifically those that have no demonstrated relatives outside... Caucasians, East Asia is a subregion of Asia. It covers about 6,640,000 km², or 15 percent of the continent. The following countries are located in East Asia: The Peoples Republic of China, except for the province of Qinghai and the autonomous regions of Xinjiang and Tibet, which may... East Asians, Australopapuans and Native Americans (also Indians, Aboriginal Peoples, American Indians, First Nations, Alaskan Natives, or Indigenous Peoples of America) are the indigenous inhabitants of The Americas prior to the European colonization, and their modern descendants. This term comprises a large number of distinct tribes, states, and ethnic groups, many of them still... 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?

Opinions vary.

What are the implications of the clinal view of human variation?

Opinions vary.

What does admixture mean for the biological validity of races?

Opinions vary.

What is the relationship between race and ethnicity?

Opinions vary.

References

• 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.