Figure 2.

Representative autoradiograph of the K-ras codon 12 point mutation analysis. Four nylon membranes, each hybridised with a different radioactively labelled oligonucleotide specific for the sequence of the wild-type codon 12 (left) and the six possible mutations (three of them depicted). On each membrane, the non-enriched PCR products are shown in the left hand lane and the mutant enriched PCR products are shown in the right hand lane. co, hybridisation controls; on each membrane cloned DNA fragments with a known codon 12 sequence complementary to the labelled oligonucleotides are used for the hybridisation of that membrane. H₂O, negative water control. pla, placenta DNA. 1 to 5, DNA isolated from postgastrectomy pancreatic cancers with mutations resulting in an amino acid change; sample 2, glycine to valine; samples 1, 3, and 4, glycine to aspartic acid; sample 5, wild-type K-ras codon 12 sequence.