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Sewall Wright

Wright in 1954
Born December 21, 1889
Melrose, Massachusetts
Died March 3, 1988 (age 98)
Madison, Wisconsin
Nationality United States
Fields genetics
Known for population genetics

Sewall Green Wright (December 21, 1889 – March 3, 1988) was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. With R. A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. He is the discoverer of the inbreeding coefficient and of methods of computing it in pedigrees. He extended this work to populations, computing the amount of inbreeding of members of populations as a result of random genetic drift, and he and Fisher pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. The work of Fisher, Wright, and Haldane on theoretical population genetics was a major step in the development of the modern evolutionary synthesis of genetics with evolution. Wright also made major contributions to mammalian genetics and biochemical genetics.

Contents

Biography

Sewall Wright was born in Melrose, Massachusetts to Philip Green Wright and Elizabeth Quincy Sewall Wright. His parents were first cousins, an interesting fact in light of Wright's later research on inbreeding. The family moved three years later after Philip accepted a teaching job at Lombard College, a Universalist college in Galesburg, Illinois.

As a child, Wright helped his father and brother print and publish an early book of poems by his father's student Carl Sandburg.

He was the oldest of three gifted brothers—the others being the aeronautical engineer Theodore Paul Wright and the political scientist Quincy Wright. From an early age Wright had a love and talent for mathematics and biology. Wright attended Galesburg High School and graduated in 1906. He then enrolled in Lombard College where his father taught, to study mathematics. He was influenced greatly by Professor Wilhelmine Entemann Key, one of the first women to receive a Ph.D. in biology. Wright received his Ph.D. from Harvard University, where he worked at the Bussey Institute with the pioneering mammalian geneticist William Ernest Castle investigating the inheritance of coat colors in mammals. He worked for the U.S. Department of Agriculture until 1925, when he joined the Department of Zoology at the University of Chicago. He remained there until his retirement in 1955, when he moved to the University of Wisconsin–Madison. He received many honors in his long career, including the National Medal of Science, the Balzan Prize (1984), and the Darwin Medal of the Royal Society. He was a member of the National Academy of Science and a Foreign Member of the Royal Society.

Wright married Louise Lane Williams (1895–1975) in 1921. They had three children: Richard, Robert, and Elizabeth.

Scientific achievements and credits

His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or fitness landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.

Wright's explanation for stasis was that organisms come to occupy adaptive peaks. In order to evolve to another, higher peak, the species would first have to pass through a valley of maladaptive intermediate stages. This could happen by genetic drift if the population is small enough. If a species was divided into small populations, some could find higher peaks. If there was some gene flow between the populations, these adaptations could spread to the rest of the species. This was Wright's shifting balance theory of evolution. There has been much skepticism among evolutionary biologists as to whether these rather delicate conditions hold often in natural populations. Wright had a long standing and bitter debate about this with R. A. Fisher, who felt that most populations in nature were too large for these effects of genetic drift to be important.

Wright strongly influenced Jay Lush, who was the most influential figure in introducing quantitative genetics into animal and plant breeding. Wright's statistical method of path analysis, which he invented in 1921 and which was one of the first methods using a graphical model, is still widely used in social science. He was a hugely influential reviewer of manuscripts, as one of the most frequent reviewers for Genetics. Such was his reputation that he was often credited with reviews that he did not write.

From 1915 to 1925 Wright was employed by the Animal Husbandry Division of the U.S. Bureau of Animal Husbandry. His main project was to investigate the inbreeding that had occurred in the artificial selection that resulted in the leading breeds of livestock used in American beef production. He also performed experiments with 80,000 guinea pigs in the study of physiological genetics. Further more he analyzed characters of some 40,000 guinea pigs in 23 strains of brother-sister matings against a random-bred stock. (Wright 1922a-c). The concentrated study of these two groups of mammals eventually led to the Shifting Balance Theory and the concept of "surfaces of selective value" in 1932. (Wright 1988 Pg 122 American Naturalist)

He did major work on the genetics of guinea pigs, and many of his students became influential in the development of mammalian genetics. He appreciated as early as 1917 that genes acted by controlling enzymes.

An anecdote about Wright, disclaimed by Wright himself, describes a lecture during which Wright tucked an unruly guinea pig under his armpit, where he usually held a chalkboard eraser: according to the anecdote, at the conclusion of the lecture, Wright absent-mindedly began to erase the blackboard using the guinea pig.

Wright and philosophy

Wright was one of the few geneticists of his time to venture into philosophy. He found a union of concept in Charles Hartshorne, who became a lifelong friend and philosophical collaborator. Wright believed that the birth of the consciousness was not due to a mysterious property of increasing complexity, but rather an inherent property, therefore implying these properties were in the most elementary particles.

Legacy

Wright and Fisher, along with J.B.S. Haldane, were the key figures in the modern synthesis that brought genetics and evolution together. Their work was essential to the contributions of Dobzhansky, Mayr, Simpson, Julian Huxley, and Stebbins. The modern synthesis was the most important development in evolutionary biology after Darwin. Wright also had a major effect on the development of mammalian genetics and biochemical genetics.

References

Bibliography

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Books by Wright

  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 1 (Genetic & Biometric Foundations); New Edition. University of Chicago Press. ISBN 0-226-91038-5.  
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 2 (Theory of Gene Frequencies); New Edition. University of Chicago Press. ISBN 0-226-91039-3.  
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 3 (Experimental Results and Evolutionary Deductions); New Edition. University of Chicago Press. ISBN 0-226-91040-7.  
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 4 (Variability within and Among Natural Populations); New Edition. University of Chicago Press. ISBN 0-226-91041-5.  

External links


Genealogy

Up to date as of February 01, 2010
(Redirected to Sewall Green Wright (1889-1988) article)

From Familypedia

Sewall Green Wright 
Birth December 21, 1889
Death: March 3, 1988
Father: Philip Green Wright (1860-1934)
Mother: Elizabeth Quincy Sewall (1865-1952)
Wife: Louise Lane Williams (1895-1975)
Wedding: 1921
Sex:
Edit facts

Sewall Green Wright was born 21 December 1889 to Philip Green Wright (1860-1934) and Elizabeth Quincy Sewall (1865-1952) and died 3 March 1988 at the age of 98 years of complications from a fractured pelvis. Sewall married Louise Lane Williams 1921 .

Biography

Template:Infobox ScientistSewall Green Wright (December 21, 1889 - March 3, 1988) was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. With R. A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. He is the discoverer of the inbreeding coefficient and of methods of computing it in pedigrees. He extended this work to populations, computing the amount of inbreeding of members of populations as a result of random genetic drift, and he and Fisher pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. The work of Fisher, Wright, and Haldane on theoretical population genetics was a major step in the development of the modern evolutionary synthesis of genetics with evolution. Wright also made major contributions to mammalian genetics and biochemical genetics.

Biography

Sewall Wright was born in Melrose, Massachusetts to Philip Green Wright and Elizabeth Quincy Sewall Wright. His parents were first cousins, an interesting fact in light of Wright's later research on inbreeding. The family moved three years later after Philip accepted a teaching job at Lombard College, a Universalist college in Galesburg, Illinois.

As a child, Wright helped his father and brother print and publish an early book of poems by his father's student Carl Sandburg.

He was the oldest of three gifted brothers – the others being the aeronautical engineer Theodore Paul Wright and the political scientist Quincy Wright. From an early age Wright had a love and talent for mathematics and biology. Wright attended Galesburg High School and graduated in 1906. He then enrolled in Lombard College where his father taught, to study mathematics. He was influenced greatly by Professor Wilhelmine Entemann Key, one of the first women to receive a Ph.D. in biology. Wright received his Ph.D. from Harvard University, where he worked at the Bussey Institute with the pioneering mammalian geneticist William Ernest Castle investigating the inheritance of coat colors in mammals. He worked for the U.S. Department of Agriculture until 1925, when he joined the Department of Zoology at the University of Chicago. He remained there until his retirement in 1955, when he moved to the University of Wisconsin-Madison. He received many honors in his long career, including the National Medal of Science, the Balzan Prize, and the Darwin Medal of the Royal Society. He was a member of the National Academy of Science and a Foreign Member of the Royal Society.

Wright married Louise Lane Williams (1895-1975) in 1921. They had three children: Richard, Robert, and Elizabeth.

Scientific achievements and credits

His papers on inbreeding, mating systems, and genetic drift make him a principal founder of theoretical population genetics, along with R. A. Fisher and J. B. S. Haldane. Their theoretical work is the origin of the modern evolutionary synthesis or neodarwinian synthesis. Wright was the inventor/discoverer of the inbreeding coefficient and F-statistics, standard tools in population genetics. He was the chief developer of the mathematical theory of genetic drift, which is sometimes known as the Sewall Wright effect, cumulative stochastic changes in gene frequencies that arise from random births, deaths, and Mendelian segregations in reproduction. Wright was convinced that the interaction of genetic drift and the other evolutionary forces was important in the process of adaptation. He described the relationship between genotype or phenotype and fitness as fitness surfaces or fitness landscapes. On these landscapes mean population fitness was the height, plotted against horizontal axes representing the allele frequencies or the average phenotypes of the population. Natural selection would lead to a population climbing the nearest peak, while genetic drift would cause random wandering.

Wright's explanation for stasis was that organisms come to occupy adaptive peaks. In order to evolve to another, higher peak, the species would first have to pass through a valley of maladaptive intermediate stages. This could happen by genetic drift if the population is small enough. If a species was divided into small populations, some could find higher peaks. If there was some gene flow between the populations, these adaptations could spread to the rest of the species. This was Wright's shifting balance theory of evolution. There has been much skepticism among evolutionary biologists as to whether these rather delicate conditions hold often in natural populations. Wright had a long standing and bitter debate about this with R. A. Fisher, who felt that most populations in nature were too large for these effects of genetic drift to be important.

An anecdote about Wright, disclaimed by Wright himself, describes a lecture during which Wright tucked an unruly guinea pig under his armpit, where he usually held a chalkboard eraser: according to the anecdote, at the conclusion of the lecture, Wright absent-mindedly began to erase the blackboard using the guinea pig.

Wright and philosophy

Wright was one of the few geneticists of his time to venture into philosophy. He found a union of concept in Charles Hartshorne, who became a lifelong friend and philosophical collaborator. Wright believed that the birth of the consciousness was not due to a mysterious property of increasing complexity, but rather an inherent property, therefore implying these properties were in the most elementary particles.

Legacy

Wright and Fisher, along with J.B.S. Haldane, were the key figures in the modern synthesis that brought genetics and evolution together. Their work was essential to the contributions of Dobzhansky, Mayr, Simpson, Julian Huxley, and Stebbins. The modern synthesis was the most important development in evolutionary biology after Darwin. Wright also had a major effect on the development of mammalian genetics and biochemical genetics.

References

Bibliography

Books by Wright

  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 1 (Genetic & Biometric Foundations); New Edition. University of Chicago Press. ISBN 0-226-91038-5. 
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 2 (Theory of Gene Frequencies); New Edition. University of Chicago Press. ISBN 0-226-91039-3. 
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 3 (Experimental Results and Evolutionary Deductions); New Edition. University of Chicago Press. ISBN 0-226-91040-7. 
  • Wright, Sewall (1984). Evolution and the Genetics of Populations: Genetics and Biometric Foundations v. 4 (Variability within and Among Natural Populations); New Edition. University of Chicago Press. ISBN 0-226-91041-5. 

External links

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Citations and remarks

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This article uses material from the "Sewall Green Wright (1889-1988)" article on the Genealogy wiki at Wikia and is licensed under the Creative Commons Attribution-Share Alike License.

Simple English

Sewall Green Wright (21 December 1889 – 3 March 1988) was an American geneticist. He was a founder of population genetics, and contributed to evolutionary theory. His work on path analysis was also notable.

With R.A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. He is the discoverer of the inbreeding coefficient and of methods of computing it in pedigrees. He extended this work to populations, calculating the degree of inbreeding of members of populations as a result of random genetic drift. Together with Fisher, he pioneered methods for calculating the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. The work of Fisher, Wright, and Haldane on theoretical population genetics was a major step in the development of the modern evolutionary synthesis of genetics with evolution. Wright also made contributions to mammalian genetics and biochemical genetics.[1]

Genetic drift

Wright's explanation for stasis[2] was that organisms come to occupy adaptive peaks. In order to evolve to another, higher peak, the species would first have to pass through a valley of maladaptive intermediate stages. This could happen by genetic drift if the population is small enough. If a species was divided into small populations, some could find higher peaks. If there was some gene flow between the populations, these adaptations could spread to the rest of the species. This was Wright's shifting balance theory of evolution. There has been much skepticism among evolutionary biologists as to whether these rather delicate conditions hold often in natural populations. Wright had a long standing and sometimes bitter debate about this with R.A. Fisher, who felt that most populations in nature were too large for the effects of genetic drift to be important. Research by Dobzhansky and E.B. Ford showed that natural selection in the field was a much stronger force that Wright had expected. Wright's own biographer now doubts the validity of Wright's idea.[3]

Anecdote

An anecdote about Wright, disclaimed by Wright himself, describes a lecture during which Wright tucked an unruly guinea pig under his armpit, where he usually held a chalkboard eraser: at the end of the lecture, Wright absent-mindedly erased the blackboard with the guinea pig.

References

  1. Provine, William B. 1986. Sewall Wright and evolutionary biology. Chicago.
  2. lack of evolutionary change
  3. Provine, William B. 2001. The origins of theoretical population genetics, with a new Afterword. Chicago. p201
  • Wright, Sewall. 1984. Evolution and the genetics of populations: genetics and biometric foundations, 4 volumes. Chicago.

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