Alfred Sturtevant
Encyclopedia
Alfred Henry Sturtevant (November 21, 1891 – April 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
.
, United States on November 21, 1891, the youngest of Alfred Henry and Harriet Sturtevant's six children. His grandfather Julian M. Sturtevant, a Yale University
graduate, founded Illinois College
where his father taught mathematics.
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
, a linguist, who taught nearby. Edgar taught Alfred about scholarship and research.
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, Sturtevant completed his doctoral work under Morgan as well.
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, the eldest of whom was William C. Sturtevant
.
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. He was elected a Fellow of the American Academy of Arts and Sciences
in 1949. Sturtevant was awarded the John J. Carty Award from the National Academy of Sciences
in 1965 . In 1967, he received the National Medal of Science
for his longtime work on the genetics of Drosophila and other organisms.
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. He died in Pasadena, California at the age of 78.
. 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 funding 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 time frame, 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.
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.
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 time frame, 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.
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.
In 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.
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 p. 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 George Beadle claimed that modern biochemical genetics stems directly from Sturtevant’s work. In a line of genetic and scientific research, Esther Lederberg
was an able student of Sturtevant and the continuing legacy of Beadle and others, such as Edward Lawrie Tatum
, Milislav Demerec
and Alexander Hollaender.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
geneticist
Geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...
. Sturtevant constructed the first genetic map of a chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
in 1913. Throughout his career he worked on the organism Drosophila melanogaster
Drosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...
with Thomas Hunt Morgan
Thomas Hunt Morgan
Thomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...
. 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
Sturt
Sturt is a surname, and may refer to:* Charles Sturt , an English explorer of Australia* George Sturt , an English writer on rural crafts and affairs who also wrote under the pseudonym George Bourne* Henry Sturt, 1st Baron Alington...
in his honor. In 1967, Sturtevant received the National Medal of Science
National Medal of Science
The National Medal of Science is an honor bestowed 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 sciences, biology, chemistry, engineering, mathematics and...
.
Biography
Alfred Henry Sturtevant was born in Jacksonville, IllinoisJacksonville, Illinois
Jacksonville is a city in Morgan County, Illinois, United States. The population was 18,940 at the 2000 census. It is the county seat of Morgan County....
, United States on November 21, 1891, the youngest of Alfred Henry and Harriet Sturtevant's six children. His grandfather Julian M. Sturtevant, a Yale University
Yale University
Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...
graduate, founded Illinois College
Illinois College
Illinois College is a private, liberal arts college, affiliated with the United Church of Christ and the Presbyterian Church , and located in Jacksonville, Illinois. It was the second college founded in Illinois, but the first to grant a degree . It was founded in 1829 by the Illinois Band,...
where his father taught mathematics.
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
Columbia University
Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...
. During this time, he lived with his older brother Edgar
Edgar H. Sturtevant
-Biography:Sturtevant was born in Jacksonville, Illinois, the older brother of Alfred Sturtevant. He studied at the University of Chicago receiving there in 1901 a Ph.D. with a dissertation on Latin case forms. He became an assistant professor of classical philology at Columbia University in New...
, a linguist, who taught nearby. Edgar taught Alfred about scholarship and research.
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
Thomas Hunt Morgan
Thomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...
, who encouraged him to publish a paper of his pedigrees shown through Mendelian genetics. In 1914, Sturtevant completed his doctoral work under Morgan as well.
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
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
. In 1922, he married Phoebe Curtis Reed, and the couple subsequently had three children, the eldest of whom was William C. Sturtevant
William C. Sturtevant
Dr. William C. Sturtevant was an anthropologist and ethnologist.He is best known as the general editor of the 20-volume Handbook of North American Indians....
.
In 1928, the Sturtevant moved to Pasadena to work at the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
, 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. He was elected a Fellow of the American Academy of Arts and Sciences
American Academy of Arts and Sciences
The American Academy of Arts and Sciences is an independent policy research center that conducts multidisciplinary studies of complex and emerging problems. The Academy’s elected members are leaders in the academic disciplines, the arts, business, and public affairs.James Bowdoin, John Adams, and...
in 1949. Sturtevant was awarded the John J. Carty Award from the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
in 1965 . In 1967, he received the National Medal of Science
National Medal of Science
The National Medal of Science is an honor bestowed 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 sciences, biology, chemistry, engineering, mathematics and...
for his longtime work on the genetics of Drosophila and other organisms.
Sturtevant was interested in taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
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. He died in Pasadena, California at the age of 78.
Historical context
Sturtevant accomplished most of his work between 1910 and World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. These years saw both World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
and the Great Depression
Great Depression
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s...
. Prior to WWII, universities and research programs operated under private donations; the federal government was not very involved in the funding of scientific research. Much research prior to WWII concerned the chemical nature of heredity
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
. 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 time frame, Sturtevant was an outspoken opponent of eugenics
Eugenics
Eugenics is the "applied science or the bio-social movement which advocates the use of practices aimed at improving the genetic composition of a population", usually referring to human populations. The origins of the concept of eugenics began with certain interpretations of Mendelian inheritance,...
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.
Genetic research prior to Sturtevant
In 1865, Gregor MendelGregor Mendel
Gregor Johann Mendel was an Austrian scientist and Augustinian friar who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance...
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.
1865 to 1900 saw a time of theory formulation in the field of heredity/genetics. In 1883, Wilhelm Roux
Wilhelm Roux
Wilhelm Roux was a German zoologist and pioneer of experimental embryology.Roux was born and educated in Jena, Germany where he attended university and studied under Ernst Haeckel. He also attended university in Berlin and Strasbourg and studied under Gustav Schwalbe, Friedrich Daniel von...
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 time frame, Hugo de Vries
Hugo de Vries
Hugo Marie de Vries ForMemRS was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation...
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.
From 1900 – 1909, anomalous data began to accumulate. Gene linkage was first reported by Carl Correns
Carl Correns
Carl Erich Correns 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 Mendel's earlier paper on that subject, which he achieved simultaneously but independently of the botanists Erich...
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.
Sturtevant's work and its 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).In 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
Sexual selection
Sexual selection, a concept introduced by Charles Darwin in his 1859 book On the Origin of Species, is a significant element of his theory of natural selection...
and development and displayed the importance of chromosomal crossing-over in mutations.
One of Sturtevant’s principle contributions was his introduction to the concept that the frequency of crossing-over
Chromosomal crossover
Chromosomal crossover is an exchange of genetic material between homologous chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis in a process called synapsis. Synapsis begins before the synaptonemal complex develops, and is not completed...
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 p. 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 George Beadle claimed that modern biochemical genetics stems directly from Sturtevant’s work. In a line of genetic and scientific research, Esther Lederberg
Esther Lederberg
Esther Miriam Zimmer Lederberg was an American microbiologist and immunologist and pioneer of bacterial genetics...
was an able student of Sturtevant and the continuing legacy of Beadle and others, such as Edward Lawrie Tatum
Edward Lawrie Tatum
Edward Lawrie Tatum was an American geneticist. He shared half of the Nobel Prize in Physiology or Medicine in 1958 with George Wells Beadle for showing that genes control individual steps in metabolism...
, Milislav Demerec
Milislav Demerec
Milislav Demerec was a Croatian-American geneticist, and the director of the Department of Genetics, Carnegie Institution of Washington [CIW], now Cold Spring Harbor Laboratory from 1941 to 1960, recruiting Barbara McClintock and Alfred Hershey.Demerec was born and raised in Kostajnica...
and Alexander Hollaender.
Key publications
- http://www.esp.org/foundations/genetics/classical/holdings/s/ahs-13.pdf 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
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 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.
- Edelman, Isidore S. and Gerald D. Fischbach. Genes and Genomes: Impact on Medicine and Society. Genes, Genomes, and Evolution Symposium. Columbia 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.
- 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/readbook.html>
- Sturtevant, A.H., and G.W. Beadle. An Introduction to Genetics. Philadelphia, PA: W.B. Saunders Company, 1940.