Curt Stern

Curt Stern (August 30, 1902 – October 23, 1981) was a German-born American geneticist.

Curt Jacob Stern was born in Hamburg, Germany. He studied zoology at the University of Berlin and received his PhD in 1923 at the age of 21. He was awarded a post-graduate fellowship at Columbia University, then the site of Thomas Hunt Morgan's famous Fly Room (so-named for the fruit fly Drosophila, the subject of genetic research for Morgan).

Although Stern accepted an appointment at the University of Berlin after his fellowship ended, he returned to the United States in 1932 and became an American citizen in 1939. From 1933 to 1947, he taught at the University of Rochester. From 1947 until his retirement in 1970, he was a professor at the University of California at Berkeley, where he had numerous doctoral students.

In 1931, Stern was the first to demonstrate crossover of homologous chromosomes in Drosophila melanogaster, only weeks after Barbara McClintock and Harriet Creighton had done so in maize (corn). In 1936, he demonstrated that recombination can also take place in mitosis resulting in somatic mosaics, organisms that contain two or more genetically distinct types of tissues. He later demonstrated that there were multiple genes on the Drosophila Y chromosome, and described the mechanism of dosage compensation.

During World War II, he led research for the American government on low-dose radiation safety. His laboratory group concluded that there is no "safe" threshold below which radiation is not harmful.