The Apportionment of Human Diversity

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"The Apportionment of Human Diversity" is a 1972 paper on racial categorisation by American evolutionary biologist Richard Lewontin. [1] In it, Lewontin presented an analysis of genetic diversity amongst people from different conventionally-defined races. His main finding, that there is more genetic variation within these populations than between them, [2] is considered a landmark in the study of human genetic variation and contributed to the abandonment of race as a scientific concept. [3] [4] [5]

Contents

Background

By the 1960s, anthropologists such as Frank B. Livingstone had concluded that "there are no races, there are only clines" – smooth gradients of genetic variation in a species across its geographic range. Lewontin's mentor Theodosius Dobzhansky challenged this, arguing that there are human discrete populations that can be distinguished by differences in the frequency of genetic traits, which he called races. [6] At that time the debate was largely semantic, stemming from their different ideas about what race is and how it would be manifested in humans genetics. [6] [7] The evidence that was available to Livingstone and Dobzhansky was mostly limited to qualitative observations of phenotypes thought to express genetic variation (e.g. skin colour). [6] This changed over the course of the 1960s, as new techniques began to produce direct evidence for genetic variation in humans at a molecular level. [8] By 1972, when Dobzhansky invited Lewontin to contribute to his edited volume of Evolutionary Biology, Lewontin felt that there was sufficient data to look at the problem anew, from a "firm quantitative basis": [8]

And so I thought, 'Well, we've got enough of this data, let's see what it tells us about the differences between human groups'. And so I just looked into the literature, and that literature was in books and so on. [...] One day I was going to give a lecture, I think it was in Carbondale, Illinois, or somewhere south. I was working in Chicago at the time. So I took a couple of these books with me and a pad of paper, and a table of logarithms which I needed for this purpose, and a little hand calculator, and I sat on this bus trip for three or four hours looking at the books, picking out the data, looking it up in the table of logarithms, doing a calculation, and writing it down in tables. And when I got back after the round trip I had all the data I needed to write the paper about how much human genetic variation there was, and so I did it.

— Richard Lewontin, in an interview in 2003. [8]

Lewontin had been interested in using quantitative methods to assess taxonomic categories for some time before 1972. Over a decade earlier, palaeontologist George Gaylord Simpson had invited him to co-author a second edition of his textbook Quantitative Zoology (1960), and Lewontin added a chapter on the analysis of variance. In it, he illustrated how this approach could be used distinguish geographically distinct races with the example of Drosophila persimilis , a species of fruit fly. Though the method was similar to that he would later apply to human genetic variation, he reached the opposite conclusion: there was much greater genetic variance between geographic populations than between individual fruit flies, so there was a reasonable basis for distinguishing taxonomic races. [8] Foreshadowing his later work on human genetic variation, he also emphasised that, because there will always be measurable differences between any two populations, it is the degree of difference compared to other axes of variation that will determine whether a grouping is biologically significant. [8] "The Apportionment of Human Diversity" was published in an volume dedicated to Simpson, perhaps prompting Lewontin to recall this previous work. [8]

Findings

Lewontin performed a statistical analysis of the fixation index (FST) in populations drawn from seven classically-defined "races" (Caucasian, African, Mongoloid, South Asian Aborigines, Amerinds, Oceanians, and Australian Aborigines). At that time, direct sequence data from the human genome was not sufficiently available, so he instead used 17 indirect markers, including blood group proteins. Lewontin found that the majority of the total genetic variation between humans (i.e., of the 0.1% of DNA that varies between individuals), 85.4%, is found within populations, 8.3% of the variation is found between populations within a "race", and only 6.3% was found to account for the racial classification. Numerous later studies have confirmed his findings. [9] Based on this analysis, Lewontin concluded, "Since such racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance."[ page needed ]

Legacy

Many subsequent studies confirmed Lewontin's main finding. [10] [11] [12]

The paper was not frequently cited in the years following its publication. [2] [13]

Fifty years after its publication, the paper was found to be frequently referenced in social media. [13] In particular, Twitter users associated with far-right politics commonly used the term "Lewontin's fallacy" (referencing A. W. F. Edwards' 2003 critique of Lewontin, "Human Genetic Diversity: Lewontin's Fallacy") as a rhetorical device to dismiss scientific arguments against biological race. [13] Commenting on the enduring significance afforded to Lewontin's paper in far-right and white nationalist discourse, geneticists Jedidiah Carlson and Kelley Harris proposed that "rejection of Lewontin's interpretation has become a tenet of white nationalist ideology". [13]

In 2022, a special issue of the journal Philosophical Transactions of the Royal Society B: Biological Sciences was published with the theme "Celebrating 50 years since Lewontin's apportionment of human diversity", [14] and a section of the book Remapping Race in a Global Context was devoted to discussing Lewontin's paper and defending it against Edwards' critique. [15]

Related Research Articles

Race is a categorization of humans based on shared physical or social qualities into groups generally viewed as distinct within a given society. The term came into common usage during the 16th century, when it was used to refer to groups of various kinds, including those characterized by close kinship relations. By the 17th century, the term began to refer to physical (phenotypical) traits, and then later to national affiliations. Modern science regards race as a social construct, an identity which is assigned based on rules made by society. While partly based on physical similarities within groups, race does not have an inherent physical or biological meaning. The concept of race is foundational to racism, the belief that humans can be divided based on the superiority of one race over another.

<span class="mw-page-title-main">Theodosius Dobzhansky</span> Russian-American geneticist and evolutionary biologist (1900–1975)

Theodosius Grigorievich Dobzhansky was a prominent geneticist and evolutionary biologist. He was a central figure in the field of evolutionary biology for his work in shaping the modern synthesis. Born in the Russian Empire, Dobzhansky emigrated to the United States in 1927, aged 27.

<span class="mw-page-title-main">Modern synthesis (20th century)</span> Fusion of natural selection with Mendelian inheritance

The modern synthesis was the early 20th-century synthesis of Charles Darwin's theory of evolution and Gregor Mendel's ideas on heredity into a joint mathematical framework. Julian Huxley coined the term in his 1942 book, Evolution: The Modern Synthesis.

<span class="mw-page-title-main">Luigi Luca Cavalli-Sforza</span> Italian population geneticist (1922–2018)

Luigi Luca Cavalli-Sforza was an Italian geneticist. He was a population geneticist who taught at the University of Parma, the University of Pavia and then at Stanford University.

Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.

<span class="mw-page-title-main">Richard Lewontin</span> American evolutionary biologist and mathematician (1929–2021)

Richard Charles Lewontin was an American evolutionary biologist, mathematician, geneticist, and social commentator. A leader in developing the mathematical basis of population genetics and evolutionary theory, he applied techniques from molecular biology, such as gel electrophoresis, to questions of genetic variation and evolution.

<span class="mw-page-title-main">Genetic variation</span> Difference in DNA among individuals or populations

Genetic variation is the difference in DNA among individuals or the differences between populations among the same species. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as well.

Ecological genetics is the study of genetics in natural populations. Traits in a population can be observed and quantified to represent a species adapting to a changing environment.

<span class="mw-page-title-main">Index of evolutionary biology articles</span>

This is a list of topics in evolutionary biology.

In population genetics, F-statistics describe the statistically expected level of heterozygosity in a population; more specifically the expected degree of (usually) a reduction in heterozygosity when compared to Hardy–Weinberg expectation.

<i>Genetics and the Origin of Species</i> 1937 book by Theodosius Dobzhansky

Genetics and the Origin of Species is a 1937 book by the Ukrainian-American evolutionary biologist Theodosius Dobzhansky. It is regarded as one of the most important works of modern synthesis and was one of the earliest. The book popularized the work of population genetics to other biologists and influenced their appreciation for the genetic basis of evolution. In his book, Dobzhansky applied the theoretical work of Sewall Wright (1889–1988) to the study of natural populations, allowing him to address evolutionary problems in a novel way during his time. Dobzhansky implements theories of mutation, natural selection, and speciation throughout his book to explain the habits of populations and the resulting effects on their genetic behavior. The book explains evolution in depth as a process over time that accounts for the diversity of all life on Earth. The study of evolution was present, but greatly neglected at the time. Dobzhansky illustrates that evolution regarding the origin and nature of species during this time in history was deemed mysterious, but had expanding potential for progress to be made in its field.

Researchers have investigated the relationship between race and genetics as part of efforts to understand how biology may or may not contribute to human racial categorization.

<span class="mw-page-title-main">G. Ledyard Stebbins</span> American botanist and geneticist (1906-2000)

George Ledyard Stebbins Jr. was an American botanist and geneticist who is widely regarded as one of the leading evolutionary biologists of the 20th century. Stebbins received his Ph.D. in botany from Harvard University in 1931. He went on to the University of California, Berkeley, where his work with E. B. Babcock on the genetic evolution of plant species, and his association with a group of evolutionary biologists known as the Bay Area Biosystematists, led him to develop a comprehensive synthesis of plant evolution incorporating genetics.

<span class="mw-page-title-main">A. W. F. Edwards</span> British statistician and geneticist (born 1935)

Anthony William Fairbank Edwards, FRS is a British statistician, geneticist and evolutionary biologist. He is the son of the surgeon Harold C. Edwards, and brother of medical geneticist John H. Edwards. He has sometimes been called "Fisher's Edwards" to distinguish him from his brother, because he was mentored by Ronald Fisher. Edwards has always had a high regard for Fisher's scientific contributions and has written extensively on them. To mark the Fisher centenary in 1990, Edwards proposed a commemorative Sir Ronald Fisher window be installed in the Dining Hall of Gonville & Caius College. When the window was removed in 2020, he vigorously opposed the move.

"Human Genetic Diversity: Lewontin's Fallacy" is a 2003 paper by A. W. F. Edwards. He criticises an argument first made in Richard Lewontin's 1972 article "The Apportionment of Human Diversity", that the practice of dividing humanity into races is taxonomically invalid because any given individual will often have more in common genetically with members of other population groups than with members of their own. Edwards argued that this does not refute the biological reality of race since genetic analysis can usually make correct inferences about the perceived race of a person from whom a sample is taken, and that the rate of success increases when more genetic loci are examined.

<span class="mw-page-title-main">Human genetic variation</span> Genetic diversity in human populations

Human genetic variation is the genetic differences in and among populations. There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism.

Race and health refers to how being identified with a specific race influences health. Race is a complex concept that has changed across chronological eras and depends on both self-identification and social recognition. In the study of race and health, scientists organize people in racial categories depending on different factors such as: phenotype, ancestry, social identity, genetic makeup and lived experience. "Race" and ethnicity often remain undifferentiated in health research.

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<span class="mw-page-title-main">Outline of evolution</span>

The following outline is provided as an overview of and topical guide to evolution:

References

  1. ↑ Lewontin, R. C. (1972). "The Apportionment of Human Diversity". Evolutionary Biology. Vol. 6. Springer US. pp. 381–398. doi:10.1007/978-1-4684-9063-3_14. ISBN   978-1-4684-9065-7. S2CID   21095796.
  2. 1 2 Ruvulo, Maryellen; Seielstad, Mark (2001). "'The Apportionment of Human Diversity' 25 Years Later". In Singh, Rama S.; Krimbas, Costas B.; Paul, Diane B.; Beatty, John (eds.). Thinking about Evolution: Historical, Philosophical, and Political Perspectives. Cambridge University Press. pp. 141–151. ISBN   978-0-521-62070-3.
  3. ↑ Sapp, Jan (6 February 2017). "Race Finished". American Scientist.
  4. ↑ Long, Jeffrey C.; Li, Jie; Healy, Meghan E. (May 2009). "Human DNA sequences: more variation and less race". American Journal of Physical Anthropology. 139 (1): 23–34. doi:10.1002/ajpa.21011. hdl: 2027.42/62133 . ISSN   1096-8644. PMID   19226648.
  5. ↑ Graves, Joseph L. (7 August 2021). "Richard Lewontin: Race Science for the People • SftP Magazine". Science for the People Magazine.
  6. 1 2 3 Kaplan, Jonathan Michael; Winther, Rasmus Grønfeldt (December 2014). "Realism, Antirealism, and Conventionalism about Race". Philosophy of Science. 81 (5): 1039–1052. doi:10.1086/678314. ISSN   0031-8248. S2CID   55148854.
  7. ↑ Kaplan, Jonathan Michael; Winther, Rasmus Grønfeldt (2013). "Prisoners of Abstraction? The Theory and Measure of Genetic Variation, and the Very Concept of 'Race'". Biological Theory. 7 (1): 401–412. doi:10.1007/s13752-012-0048-0. S2CID   52825769.
  8. 1 2 3 4 5 6 Novembre, John (2022-06-06). "The background and legacy of Lewontin's apportionment of human genetic diversity". Philosophical Transactions of the Royal Society B: Biological Sciences. 377 (1852): 20200406. doi:10.1098/rstb.2020.0406. PMC   9014184 . PMID   35430890.
  9. ↑ Ramachandran, S.; Tang, H.; Gutenkunst, R. N.; Bustamante, C. D. (2010). "Chapter 20: Genetics and Genomics of Human Population Structure" (PDF). In Speicher, M. R.; et al. (eds.). Vogel and Motulsky's Human Genetics: Problems and Approaches. Heidelberg: Springer. p. 596. doi:10.1007/978-3-540-37654-5. ISBN   978-3-540-37653-8. Archived from the original (PDF) on 3 December 2013. Retrieved 29 October 2013.
  10. ↑ Hunley, Keith L.; Cabana, Graciela S.; Long, Jeffrey C. (2016). "The apportionment of human diversity revisited". American Journal of Physical Anthropology. 160 (4): 561–569. doi: 10.1002/ajpa.22899 . ISSN   1096-8644. PMID   26619959.
  11. ↑ Feldman, Marcus (11 December 2014). "Echoes of the Past: Hereditarianism and A Troublesome Inheritance". PLOS Genetics. 10 (12): e1004817. doi:10.1371/journal.pgen.1004817. ISSN   1553-7404. PMC   4263368 . PMID   25502763.
  12. ↑ Brown, Ryan A.; Armelagos, George J. (2001). "Apportionment of racial diversity: A review". Evolutionary Anthropology: Issues, News, and Reviews. 10 (1): 34–40. doi: 10.1002/1520-6505(2001)10:1<34::AID-EVAN1011>3.0.CO;2-P . ISSN   1520-6505. S2CID   22845356.
  13. 1 2 3 4 Carlson, Jedidiah; Harris, Kelley (2022-06-06). "The apportionment of citations: a scientometric analysis of Lewontin 1972". Philosophical Transactions of the Royal Society B: Biological Sciences. 377 (1852): 20200409. doi:10.1098/rstb.2020.0409. PMC   9019867 . PMID   35430880.
  14. ↑ "Philosophical Transactions of the Royal Society B: Biological Sciences: Vol 377, No 1852". royalsocietypublishing.org. 2022-06-06.
  15. ↑ Lorusso, Ludovica; Winther, Rasmus Grønfeldt, eds. (2022). "Part I: Lewontin (1972), 50 Years Later". Remapping Race in a Global Context. History and Philosophy of Biology. New York: Routledge. doi:10.4324/9781315208893. ISBN   9781138631434. OCLC   1260692842. S2CID   239465657.
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