Curt Stern

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Curt Stern (born August 30, 1902 in Hamburg , † October 23, 1981 in Sacramento , California ) was a German-American geneticist.

Life

Curt Stern was born in Hamburg into an upper-class German-Jewish family. His father Barned Stern ran a dental accessories company and his mother Anna was a teacher. As a child, Curt developed an interest in biology that was encouraged by his teachers and parents. In 1920 the family moved to Berlin, where Curt Stern began studying biology, which he completed with Max Hartmann in 1923 with a doctoral thesis on the cytology of protozoa of the order Heliozoa . Through the mediation of Richard Goldschmidt , the head of the animal genetics department at the Kaiser Wilhelm Institute for Biology in Berlin-Dahlem, he received a Rockefeller grant , which enabled him to spend two years researching with Thomas Hunt Morgan in Berkeley. In 1932 he returned to California for research purposes with a second Rockefeller Fellowship. In 1931 he married Evelyn Sommerfield, who was an American citizen. After the seizure of power of the Nazis in 1933 he decided with his wife not to go back to Germany and stayed in the United States, whose citizenship he accepted the 1939th He worked at the University of Rochester until 1947 . In the following years he moved to the University of California at Berkeley . As before, he worked there for Richard Goldschmidt and later became professor of zoology and genetics. In 1970 he was diagnosed with Parkinson's disease , from the sequelae of which he died in 1981.

Act

Stern made several important discoveries in genetics. He made some of his earliest discoveries in the field of Y chromosome research. He showed that there are several genes on the Y chromosome and described the mechanism of dose compensation . In 1931 he found the first evidence of crossing-over (intrachromosomal recombination) of chromosome pieces in cells, simultaneously with, but independently of, Harriet B. Creighton and Barbara McClintock .

During the Second World War he discovered that even the smallest amounts of radioactivity are enough to cause mutations in the DNA of Drosophila sperm . He concluded that there is no lower radiation dose threshold below which mutations do not occur - a fundamental finding that continues to influence the use of X-rays in medicine and political decisions in nuclear research to this day. In doing so, he supported the LNT model by Hermann Muller , who propagated the model in his 1946 Nobel Prize speech. The toxicologist Edward Calabrese later criticized the experimental starting point in Curt Stern's experiments, which served as a justification. After that, a first experiment by Stern with Warren Spencer in 1946 supported the hypothesis, but a follow-up experiment by Stern with Ernst Caspari in the same year did not. Muller, who found out about this before his Nobel speech, therefore suggested further experiments. Both studies were published in 1948 in the journal Genetics, edited by Stern, although Stern and Caspari downplayed their findings, which contradicted the other study. Stern undertook further studies with Delta Uphoff, an abridged version of which appeared in Science in 1949 and which ostensibly confirmed the LNT model with no threshold. However, they had to admit that in two of the three experiments presented there, the Drosophila strains of their control experiment without radiation had unusually low mutation rates. Complete data were never published.

In 1943, Stern pointed out that the fundamental law of population genetics - until then only ascribed to the British mathematician G. H. Hardy in the English-speaking world - was published simultaneously by Hardy and the German doctor Wilhelm Weinberg in 1908 . It is therefore called the Hardy-Weinberg Act today .

Another area of ​​Stern's work was gene regulation . His textbook “Fundamentals of Human Genetics” became very influential.

Curt Stern was an elected member of the following academic academies:

In 1950, Stern was President of the Genetics Society of America . The American Society of Human Genetics honored him with the William Allan Award in 1974 and has given the Curt Stern Award named after him since 2001 . In 1975 he received the Gregor Mendel Medal .

literature

  • Lothar Jaenicke : Curt Stern, pioneer of combination genetics in flies and humans . In: BIOspectrum . tape 12 , no. 4 , 2006, p. 452-455 ( PDF ).

Web links

swell

  1. ↑ More details in his letter to Hartmann of May 16, 1933, from Jaenicke, see Ref.
  2. ↑ Curt Stern, 1931. Recombination between genetically marked (B, car) and structurally different X chromosomes in Drosophila melanogaster (extended X = translocation of the short arm of the Y chromosome to the X and shortened X = translocation of part of the X to an fourth chromosome)
  3. ↑ C. Stern, 1936. Recombination between heterozygous X chromosomes marked with yellow (y) and singed (sn)
  4. ↑ Marcel Krok, Attack on radiation geneticists triggers furor , Science Magazine, October 18, 2011
  5. ^ Curt Stern: Wilhelm Weinberg, 1862-1937. In: Genetics . Vol. 47, No. 1, 1962, pp. 1-5.
  6. ↑ Member History: Curt Stern. American Philosophical Society, accessed December 4, 2018 .
personal data
SURNAME Stern, Curt
BRIEF DESCRIPTION German-American geneticist
DATE OF BIRTH August 30, 1902
PLACE OF BIRTH Hamburg
DATE OF DEATH October 23, 1981
Place of death Sacramento , California