Nirenberg, Marshall Warren (1927– )

US biochemist who was awarded a Nobel Prize for Physiology or Medicine in 1968 for his work in the interpretation of genetic code and its function in protein synthesis.

Nirenberg was born in New York and studied at the universities of Florida and Michigan. From 1957 he was at the National Institute of Health, later moving to the Laboratory of Biochemical Genetics at the National Heart, Lung, and Blood Institute in Bethesda, Maryland.

Nirenberg was interested in the way in which the nitrogen bases – adenine (A), cytosine (C), guanine (G), and thymine (T) – specify a particular amino acid. To simplify the task of identifying the RNA triplet (codon) responsible for each amino acid, he used a simple synthetic RNA polymer. He found that certain amino acids could be specified by more than one codon, and that some triplets did not specify an amino acid at all. These ‘nonsense’ triplets signified the beginning or the end of a sequence. He then worked on finding the orders of the letters in the triplets, and obtained unambiguous results for 60 of the possible codons.