title: Marker discrimination in transformation and mutation of pneumococcus.
abstract: Earlier investigations of pneumococcal transformation revealed a function (hex(+)) responsible for severely reducing the transformation yield of certain markers. A mutational alteration (hex(-)) responsible for the loss of this function has been transferred into a hex(+) strain to permit a comparison of the hex(+) and hex(-) phenotypes in an isogenic background. The loss of the hex(+) function results both in a loss of the capacity to eliminate the low efficiency markers in transformation and a substantial increase in the spontaneous mutation rate. These properties of the hex(-) strain could result from the loss of a capacity to eliminate certain classes of mismatched base pairs that occur as intermediates in both transformation and mutagenesis.
mesh_terms: D001483:Base Sequence; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial; D005796:Genes; D005838:Genotype; D009154:Mutation / Q000528:radiation effects*; D010641:Phenotype; D011831:Radiation Genetics; D013296:Streptococcus pneumoniae; D014170:Transformation, Genetic; D014316:Tritium; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D014316:Tritium