title: Evolutionary genetics. Directed mutations slip-sliding away?
abstract: Adaptive frameshift mutations in the lacZ gene of Escherichia coli are, unusually, nearly all short deletions, perhaps caused by slipped-strand mispairings in mononucleotide runs. But are they directed?
authors.affiliation: Center for Microbial Ecology, Michigan State University, East Lansing 48824-1325, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Lenski
authors.forename: P D
authors.initials: PD
authors.lastname: Sniegowski
mesh_terms: D000222:Adaptation, Physiological; D005075:Biological Evolution; D004926:Escherichia coli / Q000235:genetics; D009154:Mutation; D012641:Selection, Genetic; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D001616:beta-Galactosidase