Pittard, James (School of Microbiology, University of Melbourne, Victoria, Australia), and B. J. Wallace. Distribution and function of genes concerned with aromatic biosynthesis in Escherichia coli. J. Bacteriol. 91:1494-1508. 1966.-A number of mutant strains of Escherichia coli K-12, which are blocked in the biosynthesis of the aromatic amino acids, were examined biochemically to determine their particular enzymatic deficiencies. The mutations carried by these strains were mapped by use of the methods of conjugation and transduction. Structural genes for five of the enzymes of the common pathway leading to chorismate and for the two enzymes converting chorismate to phenylpyruvate and p-hydroxyphenylpyruvate, respectively, were identified. Unlike the genes of the tryptophan operon most of these genes are distributed over widely separated regions of the chromosome.