8.1 Mutation and recombination Mutation is an inherited change in the base sequence of the nucleic acid comprising the genome of an organism.Mutation usually brings about only a very small amount of genetic change in a cell. Mutant an organism whose genome carries a mutation.Depending on the mutation,a mutant may or may not show an altered phenotype from its parent
8.1 Mutation and recombination Mutation is an inherited change in the base sequence of the nucleic acid comprising the genome of an organism. Mutation usually brings about only a very small amount of genetic change in a cell. Mutant an organism whose genome carries a mutation. Depending on the mutation, a mutant may or may not show an altered phenotype from its parent
Different kinds of point mutation G.5 Normal oplicatio 8 TAC ATG Transcription UAG UAU codon Translation Faulty Nonsense Wild type mutation insenion mutation Alered reading frame Normal DNA Normal readng trame Deletion mutation TA CGG C A AT A C T
Different kinds of point mutation
Mutation *Selectable *Nonselectable Spontaneous *Induced
Mutation ❖ Selectable ❖ Nonselectable ❖ Spontaneous ❖ Induced
Nutritional mutants replica plating method The photograph on the left shows the master plate The colonies not appearing on the replica plate are marked with an X The replica plate lacked one nutrient (leucine) present in the master plate Therefore,the colonies marked with an X are leucine auxotrophs
Nutritional mutants replica plating method • The photograph on the left shows the master plate • The colonies not appearing on the replica plate are marked with an X • The replica plate lacked one nutrient (leucine) present in the master plate • Therefore, the colonies marked with an X are leucine auxotrophs
Replica plating method for detection of nutritional mutants Velveteen: sterilized Press plate Plastic hoop Velveteen onto velveteen with imprint of all Wooden block colonies Master plate;growth on complete medium Transfer imprint of colonies to frest media 个 Mutants do not grow Incubate Minimal medium All colonies grow Complete medium
Replica plating method for detection of nutritional mutants