Electrophoresis artefacts — a previously unrecognized cause of error in microsatellite analysis

While microsatellite genotyping has found wide application in many fields, a number of causes that could lead to error in microsatellite genotyping have been previously reported. Here we report another cause of error that we term ‘Electrophoresis Artefacts’ (EA), which arise when high concentrations of polymerase chain reaction (PCR) products are electrophoresed in ABI 377 automated sequencers. We describe the phenomenon of EAs, characterize PCR and gel running conditions that cause them and suggest a simple method of overcoming this problem.