Representative sequence traces of exon 6 and 7 frameshift or point mutations in the abl gene. The exon 7 deletion causes a frameshift and a premature termination codon in exon 8. The bases deleted are indicated with question marks. For exon 6 frameshift, a CAGG tetranucleotide insertion at the junction of exons 5 and 6 is indicated by a rectangular box, and a C→T silent mutation is also highlighted. A C→T mutation at nucleotide 997 in exon 6 also results in a termination codon (cag→tag). In exon 7, 2-nt deletion is marked by arrows. The sequences are compared to an Abl kinase domain reference sequence using sequencing analysis software, which aligns the sequences and highlights single or multiple mutations.