Charles Yanofsky

Charles Yanofsky was an American geneticist who provided some of the first direct experimental evidence for colinearity, the principle that the linear sequence of building blocks within a gene corresponds directly, in the same order, to the linear sequence of amino acids in the protein that gene produces. Working through the early 1960s with the tryptophan synthetase A enzyme in the bacterium Escherichia coli, Yanofsky and his collaborators mapped the precise locations of a series of mutations within the relevant gene and matched each one to the exact position of the corresponding altered amino acid within the resulting protein, confirming that genetic information is read in a straightforward linear fashion consistent with the emerging understanding of the genetic code. This finding gave strong experimental support to a central piece of what became known as the central dogma of molecular biology, the framework describing how genetic information flows from DNA to protein. Yanofsky, who spent most of his career at Stanford University, also carried out extensive later work on how bacteria regulate gene expression in response to the availability of particular amino acids, including describing the mechanism of attenuation, a form of gene regulation controlled by the process of translation itself rather than by a separate regulatory protein.