Theophilus Shickel Painter (August 22, 1889 – October 5, 1969) was an American
zoologist
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and d ...
best known for his work on the structure and function of chromosomes, especially the
sex-determination genes X and Y in humans. He was the first to discover that human sex was determined by an X/Y heteromorphic chromosomal pair mechanism.
[Rudle, Frank H. (2004)]
Theophilus Painter: First Steps Toward an Understanding of the Human Genome
, ''J. Experimental Zoology, 301A'', 375–377. Retrieved 24 Jan. 2022.
He also carried out work in identifying
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
s in fruit flies (''
Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many speci ...
''). His work exploited the giant
polytene chromosomes in the salivary glands of ''Drosophila'' and other
Diptera
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
n
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
e.
Academic administration
Painter joined the faculty at the
University of Texas
The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...
in 1916 and, except for military duty during World War I, stayed there his whole career. He was, in succession, associate professor, professor and distinguished professor of zoology. He served as acting president (1944–1946) and president (1946–1952) of the University of Texas and retired from active teaching in 1966.
Racial segregation
Painter was president of the University of Texas when Texas resident
Heman Marion Sweatt
Heman Marion Sweatt (December 11, 1912 – October 3, 1982) was an African-American civil rights activist who confronted Jim Crow laws. He is best known for the '' Sweatt v. Painter'' lawsuit, which challenged the "separate but equal" doctrine and ...
applied for and was denied admission due to his race. Subsequently, Painter was the named defendant in the civil rights case ''
Sweatt v. Painter'', 339 U.S.629 (1950), which proved an integral stepping stone in the landmark case ''
Brown v. Board of Education of Topeka, Kansas
''Brown v. Board of Education of Topeka'', 347 U.S. 483 (1954), was a landmark decision by the U.S. Supreme Court, which ruled that U.S. state laws establishing racial segregation in public schools are unconstitutional, even if the segregat ...
'' that held that "separate is inherently unequal" and led to the integration of America's public schools.
Gender research
Painter is also known for his early study of
human chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
s. In 1921 he first gave the number 24 for the count of human
meiotic
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately res ...
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s. He had tried to count the tangled mass of chromosomes he could see under a microscope in
spermatocytes in slices of
testicle
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...
and arrived at the figure of 24.
Others later repeated his experiment in other ways and agreed upon the number of 24. Popular thinking held that if there were 24 chromosomes in spermatocytes, there must be an equal number contributed by the female and the human chromosome number must be 48, which was undisputed for more than 30 years.
Then in 1955,
Joe Hin Tjio
Joe Hin Tjio (2 November 1919 – 27 November 2001), was an Indonesian-born American cytogeneticist. He was renowned as the first person to recognize the normal number of human chromosomes on December 22, 1955 at the Institute of Genetics of the ...
, using more advanced techniques, looked at the chromosomes in human
somatic cells and found 46 chromosomes. Together with
Albert Levan
Albert Levan (8 March 1905 – 28 March 1998) was a Swedish botanist and geneticist.
Albert Levan is best known today for co-authoring the report in 1956 that humans had forty-six chromosomes (instead of forty-eight, as previously believed). Th ...
, Tjio published his finding in early 1956, and the human chromosome number was finally revised.
In 1934 Painter was awarded the
Daniel Giraud Elliot Medal
The Daniel Giraud Elliot Medal is awarded by the U.S. National Academy of Sciences "for meritorious work in zoology or paleontology study published in a three- to five-year period." Named after Daniel Giraud Elliot, it was first awarded in 1917.
L ...
from the
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nat ...
.
See also
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References
External links
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{{DEFAULTSORT:Painter, Theophilius
Painter, Theophilus Shickel
Members of the United States National Academy of Sciences
Painter, Theophilus Shickel
Painter, Theophilus Shickel
Painter, Theophilus Shickel
Painter, Theophilus Shickel
Science teachers
20th-century American academics