born Dec. 4, 1908, Owosso, Mich., U.S.
died May 22, 1997, Syosset, N.Y.
U.S. biologist.
He worked principally at the Carnegie Institution in Washington, D.C. He and Salvador Luria independently demonstrated the occurrence of spontaneous mutation in both bacteriophages and hosts. Later, Hershey and Max Delbrück independently discovered the occurrence of genetic recombination in phages. Delbrück incorrectly interpreted his results, but Hershey proved that the results he had obtained were recombinations by showing that the genetic processes in question correspond with the crossing-over of parts of similar chromosomes observed in cells of higher organisms. He showed that phage DNA is the main component entering the host cell during infection and that DNA, rather than protein, is the phage's genetic material. In 1969 he shared a Nobel Prize with Luria and Delbrück.