Marshall Warren Nirenberg
American biochemist and Nobel laureate who played a major role in deciphering
the genetic code. He demonstrated that, with the exception of "nonsense
codons," each possible triplet (called a codon) of four different
kinds of nitrogen-containing bases found in deoxyribonucleic acid (DNA)
and, in some viruses, in ribonucleic acid (RNA) ultimately causes the
incorporation of a specific amino acid into a cell protein.
Nirenberg received his Ph.D. from the University of Michigan in 1957,
and that year joined the staff of the National Institutes of Health
in Bethesda, Md. His research earned him the National Medal of Science
in 1965 and the Nobel Prize for Physiology or Medicine in 1968, which
he shared with Robert William Holley and Har Gobind Khorana, whose work,
like Nirenberg's, helped to show how genetic instructions in the cell
nucleus control the composition of proteins.