New unified nomenclature for the flagellar genes of Escherichia coli and Salmonella typhimurium

E. coli and S. typhimurium are very similar in most regards. This is true of their flagellar apparatus and its underlying genetics, which is complex, involving close to 40 genes. In both species, the basic symbol is fla, but for historical reasons the extensions differ widely, bear little relationship to genome order or anything else, and include a number of examples in violation of the well-established convention of Demerec et al. We have developed a new unified nomenclature for the flagellar genes of the two species. The basic symbol fla is abandoned and is replaced by flg for those genes in flagellar region I, flh for those in region II, fli for those in region III, and flj for those in the phase 2 flagellin region of S. typhimurium. Extensions (flgA, flgB, etc.) are given in genome order. The new nomenclature has been incorporated into edition VII of the linkage map of S. typhimurium and will be incorporated into edition VII of the linkage map of E. coli to be published shortly.