Customizable BAC-based DNA markers for pulsed-field gel electrophoresis

DNA markers are used as a size reference and sample loading control during gel electrophoresis. Most markers are designed for conventional gel electrophoresis to separate DNA smaller than 20 kb. For larger molecules, pulsed-field gel electrophoresis (PFGE) marker is required. Limited PFGE markers are available because large DNA are prone to nicking and degradation, causing smeary bands. Here, we developed a robust marker based on bacterial artificial chromosomes (BACs) with bands up to 184 kb. This marker could consistently confer intense and distinct bands for accurate gel analysis in molecular biology studies, laboratory validations or clinical diagnosis.