Capillary and microelectrophoretic separations of ligase detection reaction products produced from low-abundant point mutations in genomic DNA

Capillary gel electrophoresis (CGE) and polymer‐based microelectrophoretic platforms were investigated to analyze low‐abundant point mutations in certain gene fragments with high diagnostic value for colorectal cancers. The electrophoretic separations were carried out on single‐stranded DNA (ssDNA) products generated from an allele‐specific ligation assay (ligase detection reaction, LDR), which was used to screen for a single base mutation at codon 12 in the K‐ras oncogene. The presence of the mutation generated a ssDNA fragment that was >40 base pairs (bp) in length, while the primers used for the ligation assay were