US molecular biologist. In 1972, using gene-splicing techniques developed by others, Berg spliced and combined into a single hybrid the DNA from an animal tumour virus (SV40) and the DNA from a bacterial virus. For his work on recombinant DNA, he shared the 1980 Nobel Prize for Chemistry.
Berg was born in New York and educated at Pennsylvania State University and Case Western Reserve University. Between 1955 and 1974 he held several positions at Washington University.
In 1956 Berg identified an RNA molecule (later known as a transfer RNA) that is specific to the amino acid methionine. He then perfected a method for making bacteria accept genes from other bacteria. This genetic engineering can be extremely useful for creating strains of bacteria to manufacture specific substances, such as interferon. But there are also dangers: a new, highly virulent pathogenic microorganism might accidentally be created, for example. Berg has therefore advocated restrictions on genetic engineering research.