title: Beta-galactosidase and selective neutrality.
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000235:genetics*; D005696:Galactosidases / Q000235:genetics*; D011336:Probability; D012641:Selection, Genetic; D001616:beta-Galactosidase / Q000235:genetics*
chemical_list: D005696:Galactosidases; D001616:beta-Galactosidase