title: Number of mutations required to evolve a new lactase function in Escherichia coli.
abstract: The frequency of mutation of the ebgAo allele to ebgA+ was compared with the frequency of mutation of strA+ to strA-. The observation that both spontaneous and ethyl methane sulfonate-induced mutations to ebgA+ occurred more frequently than mutations to strA- suggests that ebgA+ mutants arise as the result of single-point mutations.
mesh_terms: D000483:Alleles; D004926:Escherichia coli / Q000201:enzymology; D005696:Galactosidases / Q000096:biosynthesis*; D005796:Genes; D009154:Mutation
chemical_list: D005696:Galactosidases