Hamilton O. Smith

Hamilton O. Smith was an American microbiologist who, with Kent Wilcox, identified the first type II restriction enzyme, later named HindII, in 1970, and went on to discover the DNA methylases that work alongside restriction enzymes as part of bacterial defense systems against foreign DNA. Type II restriction enzymes cut DNA at precise, predictable recognition sites, and Smith's discovery of them gave molecular biology one of its most widely used laboratory tools, work for which he shared the 1978 Nobel Prize in Physiology or Medicine with Werner Arber and Daniel Nathans. Smith later applied sequencing methods at a genomic scale, leading the team that in 1995 produced the first complete genome sequence of a free-living organism, the bacterium Haemophilus influenzae, and he subsequently contributed to mapping the human genome. He trained in mathematics at the University of California, Berkeley and earned his medical degree from Johns Hopkins School of Medicine in 1956, later working at the Institute for Genomic Research and Celera Genomics before serving as scientific director of Synthetic Genomics, where he worked on synthetic biology and biofuel research.