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Encyclopedia > Alfred Sturtevant
Alfred Henry Sturtevant
Born November 21, 1891
Died April 5, 1970
Field Genetics
Notable prizes National Medal of Science

Alfred Henry Sturtevant (November 21, 1891April 5, 1970) was an American geneticist, Sturtevant constructed the first genetic map of a chromosome in 1913. Throughout his career he worked on the organism [[Drosophila melanogaster]] with Thomas Hunt Morgan. By watching the development of flies in which the earliest cell division produced two different genomes, he measured the embryonic distance between organs in a unit which is called the sturt in his honor. In 1967, Sturtevant received the National Medal of Science. November 21 is the 325th day of the year (326th in leap years) in the Gregorian calendar. ... Year 1891 (MDCCCXCI) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... April 5 is the 95th day of the year in the Gregorian calendar (96th in leap years). ... 1970 (MCMLXX) was a common year starting on Thursday. ... For a non-technical introduction to the topic, please see Introduction to genetics. ... National Medal of Science The National Medal of Science, also called the Presidential Medal of Science, is an honor given by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social... November 21 is the 325th day of the year (326th in leap years) in the Gregorian calendar. ... Year 1891 (MDCCCXCI) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... April 5 is the 95th day of the year in the Gregorian calendar (96th in leap years). ... 1970 (MCMLXX) was a common year starting on Thursday. ... Look up geneticist in Wiktionary, the free dictionary. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Year 1913 (MCMXIII) was a common year starting on Wednesday (link will display the full calendar). ... Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American geneticist and embryologist. ... 1967 (MCMLXVII) was a common year starting on Sunday of the Gregorian calendar (the link is to a full 1967 calendar). ... National Medal of Science The National Medal of Science, also called the Presidential Medal of Science, is an honor given by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social...

Contents

Biography

Alfred Henry Sturtevant was born in Jacksonville, Illinois on November 21, 1891, the youngest of Alfred Henry and Harriet Sturtevant’s six children. His grandfather Julian M. Sturtevant, a Yale graduate, founded Illinois College where his father taught mathematics. Illinois College is a private liberal arts college affiliated with the United Church of Christ and the Presbyterian Church (USA); it is located in Jacksonville, Illinois. ...


When Sturtevant was seven years old, his father quit his teaching job and moved the family to Alabama to pursue farming. Sturtevant attended a one room schoolhouse until entering high school in Mobile. In 1908, he enrolled at Columbia University. During this time, he lived with his older brother Edgar who taught nearby. Edgar taught Alfred about scholarship and research. Columbia University is a private research university in the United States. ...


As a child, Sturtevant had created pedigrees of his father’s horses. While in college, he read about Mendelism, which piqued Sturtevant’s interest because it could explain the traits expressed in the horse pedigrees. He further pursued his interest in genetics under Thomas Hunt Morgan, who encouraged him to publish a paper of his pedigrees shown through Mendelian genetics. In 1914, Sturtevent completed his doctoral work under Morgan as well. Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets that underlie much of genetics developed by Gregor Mendel in the latter part of the 19th century. ... Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American geneticist and embryologist. ... Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets that underlie much of genetics developed by Gregor Mendel in the latter part of the 19th century. ...


After earning his doctorate, Sturtevant stayed at Columbia as a research investigator for the Carnegie Institution of Washington. He joined Morgan’s research team in the “fly room,” in which huge advances were being made in the study of genetics through studies of the fruit fly Drosophila. In 1922, he married Phoebe Curtis Reed, and the couple subsequently had three children. Type Species Musca funebris Fabricius, 1787 Drosophila is a genus of small flies whose members are often called small fruit flies, or more appropriately vinegar flies, wine flies, pomace flies, grape flies, and picked fruit-flies. ...


In 1928, the Sturtevant moved to Pasadena to work at the California Institute of Technology, where he became a Professor of Genetics and remained for the rest of his career, except for one year when he was invited to teach in Europe. He taught an undergraduate course in genetics at Caltech and wrote a textbook with George Beadle. He became the leader of a new genetics research group at Caltech, whose members included George W. Beadle, Theodosius Dobzhansky, Sterling Emerson, and Jack Schultz. In 1967, he received the National Medal of Science for his longtime work on the genetics of Drosophila and other organisms. The California Institute of Technology (commonly referred to as Caltech)[1] is a private, coeducational university located in Pasadena, California, in the United States. ... Beadle won a Nobel Prize in 1958 George Wells Beadle (October 22, 1903 - June 9, 1989) was an American scientist in the field of genetics. ... National Medal of Science The National Medal of Science, also called the Presidential Medal of Science, is an honor given by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social...


Sturtevant was interested in taxonomy as well as genetics. He loved solving all kinds of puzzles and saw genetics as a puzzle for him to decipher. He was widely read, interested in politics, newspapers, scientific journals across many subjects and crossword puzzles. He had an impressive memory and composed and edited papers in his head before writing them down from memory. He enjoyed a long and prosperous career in genetics until his death on April 5, 1970. Look up taxonomy in Wiktionary, the free dictionary. ... For a non-technical introduction to the topic, please see Introduction to genetics. ...


Historical Context

Sturtevant accomplished most of his work between 1910 and World War II. These years saw both World War I and the Great Depression. Prior to WWII, universities and research programs operated under private donations; the federal government was not very involved in the finding of scientific research. Much research prior to WWII concerned the chemical nature of heredity. WWII changed the course of science. Focus was shifted away from biology and genetics to nuclear chemistry and physics. During and after WWII, the government became the key financial backer of scientific research, in the hopes that funding basic research would lead to technological advances. In this same timeframe, Sturtevant was an outspoken opponent of eugenics and was interested in the effects of the atomic bomb on human populations, due to his previous research on lethal genes. He warned the public of possible harmful genetic effects of nuclear fallout despite supposedly low levels of ionizing radiation. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... This article is becoming very long. ... The Great Depression was a time of economic down turn, which started after the stock market crash on October 29, 1929, known as Black Tuesday. ... Eugenics is the self-direction of human evolution: Logo from the Second International Congress of Eugenics, 1921, depicting it as a tree which unites a variety of different fields. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ...


Former Paradigm (Genetic/Hereditary Research Prior to Sturtevant)

In 1865, Gregor Mendel published a paper entitled “Experiments in Plant Hybridization,” in which he proposed the principles of heredity. This paper introduced the concept of dominant and recessive genes to explain how a characteristic can be repressed in one generation but appear in the next generation. Mendel also assumed that all hereditary factors worked independently of one another, which he explained in his law of independent assortment. Mendel’s paper did not achieve much acclaim and was largely forgotten until 1900. Gregor Johann Mendel (July 20, 1822[1] – January 6, 1884) was a Moravian[2] Augustinian priest and scientist often called the father of modern genetics for his study of the inheritance of traits in pea plants. ...


1865 to 1900 saw a time of theory formulation in the field of heredity/genetics. In 1883, Wilhelm Roux argued that the linear structure of chromosomes has an impact of making sure daughter cells get equal amounts of chromosomal material. This was the beginning of the chromosome theory; Roux viewed his findings as argument that chromosomes contain units of heredity. During this timeframe, Hugo de Vries put forth a theory that persistent hereditary units are passed through generations and that each “unit” deals with a specific characteristic and the units can combine in different ways in the offspring. Wilhelm Roux (June 9, 1850–September 15, 1924) was a German zoologist and experimental embryologist. ... This article is about the biological chromosome. ... Hugo Marie de Vries (16th February 1848-21st May 1935), a Dutch biologist, was one of three men - see also Carl Correns and Erich von Tschermak - who in 1900 rediscovered Gregor Mendels work on genetics. ...


From 1900 – 1909, anomalous data began to accumulate. Gene linkage was first reported by Carl Correns in 1900, contradicting Mendel’s law of independent assortment. Thomas Hunt Morgan was the first to provide a working hypothesis for these exceptions. He postulated that genes that remained together while being passed from generation to generation must be located on the same chromosome. Carl Erich Correns (September 10, 1864, in Munich - February 14, 1933) was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendels earlier paper on that subject, which he achieved simultaneously but independent of...


Scientific revolution/new paradigm (Sturtevant’s Work and its Impact/Importance)

Sturtevant’s most notable discoveries include the principle of genetic mapping, the first reparable gene defect, the principle of underlying fate mapping, the phenomena of unequal crossing-over, and position effect. His main contributions to science include his analysis of genetic “linkage groups,” which became classical method of chromosome mapping that we still use today. In 1913, he determined that genes were arranged on chromosomes in a linear fashion, like beads on a necklace. He also showed that the gene for any specific trait was in a fixed location (locus). It has been suggested that this article or section be merged into genetic recombination. ...


His work between 1915 and 1928, Sturtevant determined that genes of Drosophila are arranged in linear order. In 1920, he published a set of three papers under the title “Genetic Studies on Drosophila simulans,” which “proved that two closely related species had newly recurring mutations that were allelic and thus probably identical” (Provine 2). His work also helped to determine genetic role in sexual selection and development and displayed the importance of chromosomal crossing-over in mutations. Illustration from The Descent of Man and Selection in Relation to Sex by Charles Darwin showing the Tufted Coquette Lophornis ornatus, female on left, ornamented male on right. ...


One of Sturtevant’s principle contributions was his introduction to the concept that the frequency of crossing-over between two genes could help determine their proximity on a linear genetic map. His experiments determined that the frequency of double crossing over can be used to deduce gene order. He demonstrated this concept by constructing crosses of three segregating genes, called “three-factor crosses.” He found that using three genes as opposed to two provided most accurate information about gene order on chromosome. With this system, Sturtevant discovered that double crossing-over occurs at frequency of equal to or less than product of two single crossing over frequencies. He also surmised that unequal crossing-over was possibly a main force of evolution. “Sturtevant…elaborated on these ideas by incorporating the conception of linear arrangement and by constructing the first chromosome map. Double crossing over and interference were deductions that arose from this result” (Sturtevant, An Introduction to Genetics 361)


Sturtevant’s work on the Drosophila genome enabled geneticists to further map chromosomes of higher organisms, including human beings. His former Caltech research partner G.W. Beadle claimed that modern biochemical genetics stems directly from Sturtevant’s work.


Other Noteworthy contributions of Sturtevant

• Did a cross of certain eye/wing characteristics produced only 6 phenotypes when it should have produced 8. This showed that 3 of the phenotypes (and hence genotypes) were linked – to interpret results, you must assume that the genes are arranged on the chromosome in a specific order. The cross test tells us the sequence of the genes.
• Theorized that consistency of crossover values and the constant order of genes on a chromosome means that a gene occupies a fixed position in a chromosome, and the allele has the corresponding position in the homologous chromosome. The intervals between adjacent loci are crossover regions and are numbered from left to right. A chromosome map, therefore, is a chart that illustrates the spacing of the genes on a chromosome. He defined a map unit as a distance that will give (on average at standard conditions) one crossover per 100 gametes
• Sturtevant was a supported of the chromosome theory of inheritance: “several explanations of linkage have been advanced in the past, but it is now quite clear that the correct interpretation is that genes are linked because they are carried on the same chromosome.” (Sturtevant, An Introduction to Genetics 66)
• Discovered that single chromatids don’t crossover
• Invented fate mapping, which reveals how certain cells develop and most importantly where they end up in the body
• “[Sturtevant] suddenly realized that the variations in strength of linkage, already attributed by Morgan to differences in the spatial separation of genes, offered the possibility of determining sequences in the linear dimension of a chromosome. I went home and spent most of the night (to the neglect of my undergraduate homework) in producing the first chromosome map, which included the sex linked genes y, w, v, m, and r, in the order and approximately the same relative spacing that they still appear on the standard maps” (Sturtevant, A History of Genetics 47)
• “By 1915 the work with Drosophila had progressed to the point where the group at Columbia was ready to try to interpret the whole field of Mendelism in terms of the chromosome theory. The resulting book, The Mechanism of Mendelian Heredity (Morgan, Sturtevant, Muller and Bridges, 1915), is a milestone in the history of the subject.” (Sturtevant, A History of Genetics 48-49)
• “There was still much exciting and fundamental work to be done with Drosophila…but it had become a question of how the chromosome mechanism worked, not of whether it could be demonstrated to be the true mechanism” (Sturtevant, A History of Genetics 49)
• He discovered unequal crossing over – one chromosome breaks so that it yields two crossovers
• Morgan proposed (in 1911, after Sturtevant’s work/invention) that linkage is due to genes being on same chromosome (alleles being on same pair of chromosomes) – closely linked genes closer on chromosome - “Here, then, in 1911, was the essence of the chromosome interpretation of the phenomena of inheritance” (Sturtevant, A History of Genetics 44)
• Sturtevant’s most famous and revolutionary discovery, chromosome mapping, has many important uses in modern biology:
• each chromosome has a banding pattern; numbered to help identify regions of a particular chromosome
• chromosome maps have allowed for the development of karyotypes/karyotyping
• chromosome maps allows us to know where the gene for a particular trait is (ex – glaucoma on 1st chromosome – knowing location of gene allows for development of genetic tests
• helpful in establishing genome testing
• chromosome mapping details the position and spacing of “biochemical landmarks” (ex- genes)
• modern geneticists still use Sturtevant’s technique of mapping & his same map unit: 1 map unit = 1% frequency of recombination
• Mapping genes and linkage maps have important applications for medical screening. For example the muscular dystrophy gene DS is linked by 10 map units to the S locus, coding for a specific antigen that can be detected immunologicaly. These genetic tools are also quite useful for indirect selection of desirable traits, for example disease resistance, on the basis or linked markers in practical breeding. Maps are also used for evolutionary inferences among related species and for other fundamental research programs. The new field of Genomics started with the gene mapping work of T. Morgan. (Quiros) “Using the molecular techniques developed by the children of Morgan, his scientific children, they identified an abnormal mutation in a gene encoding a protein that was quite well known called synuclein, and that has proved enormous[ly] helpful in out analysis of the mechanisms of Parkinson’s Disease” (Edelman 6).
• discovered chromosome inversion: a segment of a chromosome is turned upside down and reattached to the chromosome
• balanced inversion occurs if all of the genes normally present in the uninverted chromosome are still present in the inverted chromosome; if genes get lost or duplicated, inversion is unbalanced – this can cause birth defect
• Sturtevant’s discovery of inversion is important because it explains the why/how of certain genetic defects and discovery of inversion allows for its presence to be tested for
• Genetic tests exist today for some disorders caused by inversions


Key publications

  • [1] The linear arrangement of six sex-linked factors in Drosophila, as shown by their mode of association. Journal of Experimental Zoology, 14: 43-59, 1913
  • The North American Species of Drosophila. Carnegie Institute of Washington, 1921.
  • A History of Genetics. Cold Spring Harbor Laboratory Press. Online Electronic Edition

Former Graduate Students

Edward B. Lewis Edward B. Lewis (May 20, 1918 – July 21, 2004) was an American geneticist, the winner of the 1995 Nobel Prize in Medicine. ...


References

  • Lewis, E.B. Alfred Henry Sturtevant, National Academy of Sciences Biographical Memoirs

Sources


Allan, Garland E. Isis, Vol. 66, No. 3. (Sep., 1975),pp. 332-333.


Biography.com. Sturtevant, Alfred Henry. A&E Television Networks, 2007.


Chromosome Map. NCBI. April 11, 2007 < http://www.ncbi.nlm.nih.gov/books/bv.fc gi?rid=gnd.chapter.272>


Definition of Chromosome Inversion. April 11, 2007. http://www.medterms.com/script/main/art.asp?articlekey=8183


Dorak MD, PhD, M. Tevfik. Landmarks in the History of Genetics. November 28, 2005. Accessed April 8, 2007. <http://www.dorak.info/genetics/notes01.html>


Edelman, Isidore S. and Gerald D. Fischbach. Genes and Genomes: Impact on Medicine and Society. Genes, Genomes, and Evolution Symposium. Colombia University, 16 October 2003.


Lassman, Thomas C. Government science in postwar America: Henry A. Wallace, Edward U. Condon, and the transformation of the National Bureau of Standards, 1945-1951. Isis 96.1 (March 2005): p25.


Lattas, Chelsea K. Chromosome Inversions. Michigan State University. April 11, 2007 < http://www.msu.edu/~lattasch/inversion.html>


Lewis, Edward B. Alfred Henry Sturtevant: November 21, 1891- April 5, 1970. Dictionary of Scientific Biography, vol. 13, pp.133-38. New York: Chas. Scribner’s Sons, 1976.


Lewis, E.B., ed. Genetics and Evolution: Selected Papers of A.H. Sturtevant. San Francisco: W.H. Freeman and Company, 1961.


Lorentz, Cindy Pham et al. History of Genetics and Sequencing of the Human Genome. Primer on Medical Genomics. Mayo Clinic Proceedings, August 2002, Vol 77. pp. 773-782.


Provine, William B. Alfred Henry Sturtevant and Crosses Between Drosphila melanogaster and Drosphila simulans. Genetics 129:1-5 (September 1991)



Quiros, Carlos F. Lecture 3 - Cell Division, Chromosome theory of Inheritance, Sex Linkage. November 15, 2005. University of California at Davis. April 8, 2007. <http://www.plantsciences.ucdavis.edu/bis101/lectures/lec03.html >


Steen, Francis F. Landmarks in the History of Genetics. 1998. University of California at Los Angeles. April 8, 2007. < http://cogweb.ucla.edu/ep/DNA_history.html>


Sturtevant, A.H. A History of Genetics. 2001. The Electronic Scholarly Publishing Project. April 8, 2007. < http://www.esp.org/books/sturt/history/readb ook.html>


Sturtevant, A.H., and G.W. Beadle. An Introduction to Genetics. Philadelphia, PA: W.B. Saunders Company, 1940.


  Results from FactBites:
 
Genes get shuffled when chromosomes exchange pieces. (1764 words)
Alfred Sturtevant at his desk in Caltech, 1949.
Alfred Sturtevant and Calvin Bridges were both students of Thomas Hunt Morgan.
Alfred Henry Sturtevant was born in Jacksonville, Illinois.
Genetic linkage - Wikipedia, the free encyclopedia (937 words)
The observations by Thomas Hunt Morgan that the amount of crossing over between linked genes differs led to the idea that crossover frequency might indicate the distance separating genes on the chromosome.
Morgan's student Alfred Sturtevant developed the first genetic map, also called a linkage map.
Sturtevant proposed that the greater the distance between linked genes, the greater the chance that non-sister chromatids would cross over in the region between the genes.
  More results at FactBites »

 
 

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