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Encyclopedia > Sewall Wright

Sewall Green Wright ForMemRS (December 21, 1889March 3, 1988) was an American geneticist known for his influential work on evolutionary theory. Foreign Member of the Royal Society is an honourary postition within the Royal Society. ... December 21 is the 355th day of the year (356th in leap years) in the Gregorian calendar. ... 1889 (MDCCCLXXXIX) was a common year starting on Tuesday (see link for calendar). ... March 3 is the 62nd day of the year in the Gregorian Calendar (63rd in leap years). ... 1988 (MCMLXXXVIII) was a leap year starting on Friday of the Gregorian calendar. ... Look up geneticist in Wiktionary, the free dictionary. ... This article is about biological evolution. ...

Contents


Biography

Sewall Wright was born in Melrose, Massachusetts to Philip Green and Elizabeth Quincy Sewall Wright. He was the youngest of three gifted brothers, 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, where he graduated in 1906 to enroll in Lombard College, where his father taught a number of subjects, 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 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. Melrose Veterans Memorial Middle School prior to its demolition in 2005 Melrose is a city located in the Greater Boston metropolitan area and Middlesex County, Massachusetts, United States. ... Official language(s) English Capital Boston Largest city Boston Area  Ranked 44th  - Total 10,555 sq mi (27,360 km²)  - Width 183 miles (295 km)  - Length 113 miles (182 km)  - % water 13. ... Theodore Paul Wright (1895 – 1970) was a U.S. aeronautical engineer and educator. ... Quincy Wright (1890 - 1970) was a U.S. international jurist and political scientist. ... 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ... Lombard College was a college located in Galesburg, Illinois. ... Euclid, a famous Greek mathematician known as the father of geometry, is shown here in detail from The School of Athens by Raphael. ... A doctorate is an academic degree of the highest level. ... Biology is the branch of science dealing with the study of life. ... Harvard University campus (old map) Harvard University (incorporated as The President and Fellows of Harvard College) is a private university in Cambridge, Massachusetts. ... 1925 (MCMXXV) was a common year starting on Thursday (link will take you to calendar). ... The University of Chicago is a private university located principally in the Hyde Park neighborhood of Chicago, Illinois. ... The University of Wisconsin–Madison is a public university located in Madison, Wisconsin. ... President Harding and the National Academy of Sciences at the White House, Washington, DC, April 1921 The National Academy of Sciences (NAS) is a corporation in the United States whose members serve pro bono as advisers to the nation on science, engineering, and medicine. ... The premises of the Royal Society in London (first four properties only). ...


Wright married Louise Lane Williams (1895-1975) in 1921, with whom he had three children: Richard, Robert, and Elizabeth. 1895 (MDCCCXCV) was a common year starting on Tuesday (see link for calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day-slower Julian calendar). ... 1975 (MCMLXXV) was a common year starting on Wednesday. ...


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 of the inbreeding coefficient, a standard tool 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 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. This article or section may be confusing for some readers, and should be edited to be clearer or more simplified. ... In sociobiology and behavioural ecology, the term mating system is used to describe the ways in which animal societies are structured in relation to sexual behaviour. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ... 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. ... Sir Ronald Fisher Sir Ronald Aylmer Fisher, FRS (February 17, 1890 – July 29, 1962) was an evolutionary biologist, geneticist and statistician. ... J.B.S. Haldane with his second wife Helen Spurway John Burdon Sanderson Haldane (November 5, 1892 – December 1, 1964), who normally used J.B.S. as a first name, was a British geneticist and evolutionary biologist. ... The modern evolutionary synthesis (often referred to simply as the modern synthesis or the evolutionary synthesis), neo-Darwinian synthesis or neo-Darwinism, generally denotes the combination of Charles Darwins theory of the evolution of species by natural selection, Gregor Mendels theory of genetics as the basis for biological... The modern evolutionary synthesis (often referred to simply as the modern synthesis or the evolutionary synthesis), neo-Darwinian synthesis or neo-Darwinism, generally denotes the combination of Charles Darwins theory of the evolution of species by natural selection, Gregor Mendels theory of genetics as the basis for biological... 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. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ... Stochastic, from the Greek stochos or goal, means of, relating to, or characterized by conjecture; conjectural; random. ... For other uses, see Reproduction (disambiguation) Reproduction is the biological process by which new individual organisms are produced. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ... The genotype is the specific genetic makeup (the specific genome) of an individual, usually in the form of DNA. It codes for the phenotype of that individual. ... The phenotype of an individual organism is either its total physical appearance and constitution or a specific manifestation of a trait, such as size, eye color, or behavior that varies between individuals. ... Fitness (often denoted in population genetics models) is a central concept in evolutionary theory. ... In evolutionary biology, fitness landscapes or adaptive landscapes are used to visualize the relationship between genotypes (or phenotypes) and replicatory success. ... Allele frequency is a term of population genetics that is used in characterizing the genetic diversity of a species population, or equivalently the richness of its gene pool. ... The phenotype of an individual organism is either its total physical appearance and constitution, or a specific manifestation of a trait, such as size or eye color, that varies between individuals. ... Natural selection is the process by which individual organisms with favorable traits are more likely to survive and reproduce. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ...


Wright's explanation for stasis was that organisms come to occupy adaptive peaks. In order to evolve to an other, 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 the 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. The term stasis has several meanings: A state of stabilty, in which all forces are equal and opposing, therefore they cancel out each other. ... local optimum is a term in Applied mathematics and Computer Science. ... Sir Ronald Fisher Sir Ronald Aylmer Fisher, FRS (February 17, 1890 – July 29, 1962) was an evolutionary biologist, geneticist and statistician. ... Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. ...


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. Jay Lawrence Lush (January 3, 1896 - 1982) was a pioneering animal genetist who made important contributions to livestock breeding. ... Quantitative genetics is the study of continuous traits (such as height or weight) and its underlying mechanisms. ... In project management, path analysis (also known as critical path analysis) is a technique to analyse events. ... In probability theory and statistics, a graphical model (GM) represents dependencies among random variables by a graph in which each random variable is a node. ... The social sciences are groups of academic disciplines that study the human aspects of the world. ...


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. Species Cavia porcellus Cavia aperea Cavia tschudii Cavia guianae Cavia anolaimae Cavia nana Cavia fulgida Cavia magna Guinea pigs (also called cavies) are rodents belonging to the family Caviidae and the genus Cavia. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ...


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. Philosopher in Meditation (detail), by Rembrandt. ... Charles Hartshorne (June 5, 1897 – October 9, 2000) was a prominent philosopher who concentrated primarily on the philosophy of religion and metaphysics. ...


Legacy

Wright and Fisher were the key figures in the neodarwinian synthesis that brought genetics and evolution together. Their work was essential to the contributions of Dobzhansky, Mayr, Simpson, Julian Huxley, and Stebbins. The neodarwinian 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. The modern evolutionary synthesis (often referred to simply as the modern synthesis or the evolutionary synthesis), neo-Darwinian synthesis or neo-Darwinism, generally denotes the combination of Charles Darwins theory of the evolution of species by natural selection, Gregor Mendels theory of genetics as the basis for biological... Theodosius Grigorevich Dobzhansky (Russian — Феодосий Григорьевич Добржанский; sometimes anglicized to Theodore Dobzhansky; January 25, 1900 - December 18, 1975) was a noted geneticist and evolutionary biologist. ... This article has been identified as possibly containing errors. ... George Gaylord Simpson (June 16, 1902 - October 6, 1984) was an American paleontologist. ... Sir Julian Sorell Huxley, FRS (June 22, 1887 – February 14, 1975) was a British biologist, author, Humanist and internationalist, known for his popularisations of science in books and lectures. ... G. Ledyard Stebbins George Ledyard Stebbins, Jr. ... The name Darwin may refer to various places, things, and people, including: Charles Darwin (1809–1882), renowned naturalist and thinker associated with the theory of Natural Selection Darwin, Northern Territory, Australian city and the capital of the Northern Territory Darwin (operating system), a computer operating system used in Apples...


References

  • Crow, J. F. (1988) "Sewall Wright (1889-1988)" Genetics 119 (1): 1-4.
  • Crow, J. F. and W. F. Dove. (1987) "Sewall Wright and physiological genetics" Genetics 115 (1): 1-2.
  • Ghiselin, M. T. (1997) Metaphysics and the Origin of Species. NY: SUNY Press.
  • Hill W. G. (1996) "Sewall Wright's 'Systems of Mating'" Genetics 143 (4): 1499-506.
  • Provine, W. (1986) Sewall Wright and Evolutionary Biology. Chicago, IL: University of Chicago Press.
  • Wright, S. (1932) "The roles of mutation, inbreeding, crossbreeding and selection in evolution" Proc. 6th Int. Cong. Genet. 1: 356–366.

External links

  • Sewall Wright: Darwin's Successor—Evolutionary Theorist by Edric Lescouflair and James F. Crow

Articles:

  • M. A. M. de Aguiar, H. Sayama, E. Rauch, Y. Bar-Yam, and M. Baranger: Stability and instability of polymorphic populations and the role of breeding seasons in phase III of Wright's shifting balance theory, Phys. Rev. E 65, 031909, 2002.
edit
Topics in population genetics
Key concepts: Hardy-Weinberg law | linkage disequilibrium | Fisher's fundamental theorem | neutral theory
Selection: natural | sexual | artificial | ecological
Genetic drift: small population size | population bottleneck | founder effect | coalescence
Founders: R.A. Fisher | J.B.S. Haldane | Sewall Wright
Related topics: evolution | microevolution | evolutionary game theory | fitness landscape | genetic genealogy
List of evolutionary biology topics

  Results from FactBites:
 
Sewall Wright - Wikipedia, the free encyclopedia (701 words)
Sewall Wright was born to Philip Green and Elizabeth Quincy Sewall Wright in 1889.
Wright also gave a way to visualise the relationship between genotype or phenotype and success in replication called fitness landscapes.He proposed an explanation for stasis whereby he suggested organisms come to occupy adaptive peaks.
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.
Sewall Wright - definition of Sewall Wright in Encyclopedia (216 words)
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 and many of its applications.
Wright was the developer of adaptive surfaces (fitness landscapes), and he emphasized the importance of the interaction of genetic drift and natural selection in determining the outcome of evolution.
  More results at FactBites »

 
 

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