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Richard Charles "Dick" Lewontin (born March 29, 1929) is an American evolutionary biologist, geneticist and social commentator. 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 genetic variation and evolution. In a pair of 1966 papers co-authored with J.L. Hubby in the journal Genetics, Lewontin helped set the stage for the modern field of molecular evolution.
Lewontin was born in New York City to Jewish parents. Lewontin attended Forest Hills High School and the École Libre des Hautes Études in New York. In 1951, he obtained a bachelors degree in biology from Harvard University. In 1952, he received a master's degree in mathematical statistics followed by a doctorate 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 Lewontin served as Alexander Agassiz Professor of Zoology and Professor of Biology at Harvard until 1998 and as of 2003 was the Alexander Agassiz Research Professor at Harvard. Lewontin 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, and Robert Brandon, often inviting them to work in his lab.
Work in population genetics
Lewontin has worked in both theoretical and experimental population genetics. A hallmark of his work has been an interest in new technology. He was the first person to do a computer simulation of the behavior of a single locus (previous simulation work having been of models with multiple loci). In 1960 he and Ken-Ichi Kojima were the first population geneticists to give the equations for change of haplotype frequencies with interacting natural selection at two loci. This set off a wave of theoretical work on two-locus selection in the 1960s and 1970s. 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. (An achievement that he would be less happy to claim is that he introduced the name "linkage disequilibrium" itself, one about which many population geneticists have been unenthusiastic).
In 1966, he and Jack Hubby published a paper that revolutionized population genetics. They used protein gel electrophoresis to survey dozens of loci in 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. Although they did not commit themselves to advocating neutrality, this was the first clear statement of the neutral theory for levels of variability within species. Lewontin and Hubby's paper had great impact -- the discovery of high levels of molecular variability gave population geneticists ample material to work on, and gave them access to variation at single loci. The possible theoretical explanations of this rampant polymorphism became the focus of most population genetics work thereafter. 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, Richard Lewontin identified that most of the variation (80-85%) within human populations is found within local geographic groups and differences attributable to traditional "race" groups are a minor part of human genetic variability (1-15%). Subsequent work by other researchers using more modern techniques have supported these results.
Critique of orthodox evolutionary biology
Lewontin and his late Harvard colleague Stephen Jay Gould introduced the evolutionary term spandrel, inspired by the architectural term "spandrel" and transferred the word to an evolutionary context, in an influential 1979 paper "The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme", using it for a feature of an organism that exists as a necessary consequence of other features and is not selected for directly. The relative frequency of spandrels, so defined, versus adaptive features in nature, remains a controversial topic 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, and Elliot Sober. Lewontin briefly argued for the historical nature of biological causality in "Is Nature Probable or Capricious?"
In "Organism and Environment" in 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 passive recipient of environmental influences, a correct understanding should emphasize the organism as an active constructer of its own environment. 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, K.N. Laland, and F.J. Odling-Smee among others have developed Lewontin's conception in more detailed models.
Lewontin has long been a critic of traditional neo-Darwinian approaches to adaptation. In his article "Adaptation" in the Italian Encyclopedia Einaudi, and in a toned-down version in Scientific American, he emphasized the need to give an engineering characterization of adaptation separate from measurement of number of offspring, rather than simply assuming organs or organisms are at adaptive optima. Lewontin has claimed that his more general, technical criticism of adaptationism grew out of his recognition that the fallacies of sociobiology reflect fundamentally flawed assumptions of adaptiveness of all traits in much of the modern evolutionary synthesis.
Sociobiology and evolutionary psychology
Along with others, such as Gould, Lewontin has been a persistent critic of some themes in neo-Darwinism; specifically, he has criticised sociobiologists and evolutionary psychologists such as Edward O. Wilson and Richard Dawkins, who attempt to explain animal behaviour and social structures in terms of evolutionary advantage or strategy—this has been controversial when applied to humans, because some see it as genetic determinism. Lewontin, in his writing, calls for what he considers a more nuanced view of evolution, which he claims requires a more careful understanding of the context of the whole organism as well as the environment.
Such concerns about what he views as the oversimplification of genetics led Lewontin to be a frequent commentator in debates, and he has lectured widely to promote his views on evolutionary biology and science. In books such as Not in Our Genes (co-authored with Steven Rose and Leon J. Kamin) and numerous articles, Lewontin has questioned much of the claimed heritability of human behavioral traits such as intelligence as measured by IQ tests, promoted by books such as The Bell Curve.
Lewontin has been criticized by some academics for a rejection of sociobiology for non-scientific reasons. Some credit this rejection to political beliefs (Wilson 1995). Lewontin has at times identified himself as Marxist or at least left-leaning (Levins and Lewontin 1985). Others (Kitcher 1985) have countered that Lewontin's criticisms of sociobiology are genuine scientific concerns about the discipline and claim that attacking Lewontin's motives amount to an ad hominem argument. Researchers such as Steven Pinker (2002) address Lewontin's concerns in a scientific context, but nevertheless believe that Lewontin is attacking a straw man version of sociobiology (or its more modern incarnation as evolutionary psychology) and therefore claim that his arguments miss the target.
Lewontin's Fallacy is a 2003 paper by A.W.F. Edwards that criticizes Richard Lewontin's 1972 conclusion that because the probability of racial misclassification of an individual based on variation in a single genetic locus is approximately 30%, race is an invalid taxonomic construct. A caricature of Edwards' argument is that because we can measure enough loci (the entire DNA sequence) to make us all have our own individual "cluster", we must all be of different races (barring identical twins).
Lewontin has also written on the economics of agribusiness. He has contended that hybrid corn was developed and propagated not because of its superior quality, but because it allowed agribusiness corporations to force farmers to buy new seed each year rather than plant seed produced by their previous crop of corn. Lewontin testified in an unsuccessful suit in California challenging the state's financing of research to develop automatic tomato pickers, favoring the profits of agribusiness over the employment of farm workers.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Richard_Lewontin". A list of authors is available in Wikipedia.|