J. Heinrich Matthaei (born 1929, left) and Marshall Warren Nirenberg (1927-2010, right), German and US biochemists. Matthaei and Nirenberg worked together on the protein synthesis poly-U experiments that helped identify the genetic code. From 1962, Nirenberg was head of Biochemical Genetics at the US National Institutes of Health. Matthaei was his first postdoctoral researcher. Nirenberg shared the 1968 Nobel Prize in Physiology or Medicine for his work on genetics. Controversially, Matthaei was not included in the award. Photographed circa 1961.