Mutation Base substitution .Change in one base (point mutation) 。Missense mutation .Result in change in amino acid DNA(coding strand) OACOOCA WNCC AUU DNA(coding strand) OACOUCAAAUC AUD Transcription A.N.acoNdec mRNA oAA8oo的eoAA mRNA Amino acid sequence Me Phe Stop Translation (b)Missense mutation Amino acid sequence Met Lys Phe Gly Stop (a)Normal DNA molecule Figure 8.17a,b • Base substitution (point mutation) • Missense mutation Mutation Figure 8.17a, b •Change in one base •Result in change in amino acid