Richard Charles Lewontin (March 29, 1929 – July 4, 2021) 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. He was a self-described Marxist.
In a pair of seminal 1966 papers co-authored with J. L. Hubby in the journal Genetics, Lewontin helped set the stage for the modern field of molecular evolution. In 1979, he and Stephen Jay Gould introduced the term "spandrel" into evolutionary theory. From 1973 to 1998, he held an endowed chair in zoology and biology at Harvard University, and from 2003 until his death in 2021 he was a research professor there.
From a sociological perspective, Lewontin strongly opposed genetic determinism.
Lewontin was born in New York City to parents descended from late 19th-century Ashkenazi Jewish immigrants. His father was a broker of textiles, and his mother a homemaker. He attended Forest Hills High School and the École Libre des Hautes Études in New York. In 1951 he graduated from Harvard College with a BS degree in biology. In 1952, Lewontin received an MS degree in mathematical statistics, followed by a PhD degree in zoology in 1954, both from Columbia University, where he was a student of Theodosius Dobzhansky.
Lewontin held faculty positions at North Carolina State University, the University of Rochester, and the University of Chicago. In 1973, he was appointed as Alexander Agassiz Professor of Zoology and Professor of Biology at Harvard University, a position he held until 1998.
Lewontin worked in both theoretical and experimental population genetics. A hallmark of his work was an interest in new technology. In 1960, he and Ken-Ichi Kojima gave the equations for change of haplotype frequencies with interacting natural selection at two loci. Their paper gave a theoretical derivation of the equilibria expected, and also investigated the dynamics of the model by computer iteration. Lewontin later introduced the D' measure of linkage disequilibrium.
In 1966, he and J. L. Hubby published a paper that studied the amount of heterozygosity in a population. They used protein gel electrophoresis to survey dozens of loci in the fruit fly Drosophila pseudoobscura, and reported that a large fraction of the loci were polymorphic, and that at the average locus there was about a 15% chance that the individual was heterozygous. (Harry Harris reported similar results for humans at about the same time.) Previous work with gel electrophoresis had been reports of variation in single loci and did not give any sense of how common variation was.
Lewontin and Hubby's paper also discussed the possible explanation of the high levels of variability by either balancing selection or neutral mutation. Martin Kreitman was later to do a pioneering survey of population-level variability in DNA sequences while a Ph.D. student in Lewontin's lab.
Work on human genetic diversity
In a landmark paper published in 1972, Lewontin identified that most of the variation (80–85%) within human populations is found within local geographic groups, and differences attributable to the "race" groups defined in his study are a minor part of human genetic variability (1–15%). In a 2003 paper, A. W. F. Edwards criticized Lewontin's conclusion that race is an invalid taxonomic construct, terming it Lewontin's fallacy. He showed that the probability of racial misclassification of an individual based on variation in a single genetic locus is approximately 30%, but the misclassification probability becomes close to zero if enough loci are studied. That is, it appears that a majority of genetic variation is found within groups only if a single locus is used, but the reverse is true if analyzing a multiplicity of loci. Edwards' paper was commented on by Jonathan Marks, who argued that "the point of the theory of race was to discover large clusters of people that are principally homogeneous within and heterogeneous between, contrasting groups. Lewontin's analysis shows that such groups do not exist in the human species, and Edwards' critique does not contradict that interpretation."
As of 2003, Lewontin was the Alexander Agassiz Research Professor at Harvard. He has worked with and had great influence on many philosophers of biology, including William C. Wimsatt, Elliott Sober, Philip Kitcher, Elisabeth Lloyd, Peter Godfrey-Smith, Sahotra Sarkar, and Robert Brandon, often inviting them to work in his lab.
Since 2013, Lewontin has been listed on the Advisory Council of the National Center for Science Education.
Debates within mainstream evolutionary biology
In 1975, when E. O. Wilson's book Sociobiology proposed evolutionary explanations for human social behaviors, biologists, including Lewontin and his Harvard colleagues Stephen Jay Gould and Ruth Hubbard, responded negatively.
Lewontin and Gould introduced the term spandrel to evolutionary biology, inspired by the architectural term "spandrel", in an influential 1979 paper, "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme." "Spandrels" were described as features of an organism that exist as a necessary consequence of other (perhaps adaptive) features, but do not directly improve fitness (and thus are not necessarily adaptive). This critique sparked both controversy and a revolution in the study of selection by evolutionary biologists. The subsequent 5–20 years consequently saw some of the most novel and rigorous methods to quantify selection in the wild and lab, test for selection phylogenetically, and reconcile the effects of other evolutionary processes (e.g., drift, gene flow, development, historical contingency); all of which resulted in a sort-of renaissance in evolutionary biology.
Lewontin was an early proponent of a hierarchy of levels of selection in his article, "The Units of Selection". He has been a major influence on philosophers of biology, notably William C. Wimsatt (who taught with Lewontin and Richard Levins at the University of Chicago), Robert Brandon and Elisabeth Lloyd (who studied with Lewontin as graduate students), Philip Kitcher, Elliott Sober, and Sahotra Sarkar. Lewontin briefly argued for the historical nature of biological causality in the article "Is Nature Probable or Capricious?".
In an article titled "Organism and Environment", published in the journal Scientia, and in more popular form in the last chapter of Biology as Ideology, Lewontin argued that while traditional Darwinism has portrayed the organism as a passive recipient of environmental influences, a correct understanding should emphasize the organism as an active constructor of its own environment. Ecological niches are not pre-formed, empty receptacles into which organisms are inserted, but are defined and created by organisms. The organism-environment relationship is reciprocal and dialectical. M. W. Feldman and others have developed Lewontin's conception in more detailed models under the term niche construction.
In the adaptationist view of evolution, the organism is a function of both the organism and environment, while the environment is only a function of itself. The environment is seen as autonomous and unshaped by the organism. Lewontin instead believed in a constructivist view, in which the organism is a function of the organism and environment, with the environment being a function of the organism and environment as well. This means that the organism shapes the environment as the environment shapes the organism. The organism shapes the environment for future generations.