5·TAc… Molecular ATG…5 MUTATION Normal ba f asis o Mutation A c T A C T G A T A T G · Point mutation ↓↓↓↓ Transcription Missense mutation A C U A G U AU U A C Nonsense mutation Asparagine 天so op Tyrosine Tyrosine codon 冬酰胺 codon 酪氨酸 Silent mutation Translation Faulty Incomplete Normal Normal Protein Protein Protein Protein Missense Nonsense Silent Wild type mutation mutation FIGURE 7.3 Possible effects of base pair substitution in a gene cod ing for a protein: three different protein products from changes in the DNA for a single codonMolecular basis of Mutation • Point Mutation – Missense mutation – Nonsense mutation – Silent mutation 天冬酰胺 酪氨酸