突变的两种方式 Original DNA sequence (a)Base substitution GGG AGT GTA GAT CGT GGG AGT GCA GAT CGT One codon changed A base substitution alters a single codon Three basic types of gene mutations are base substitutions. insertions. and deletions A Genetics Ch127Genetics Ch12.7 一、突变的两种方式 • Three basic types of gene mutations are base substitutions, insertions, and deletions