MPprimer: a program for reliable multiplex PCR primer design. MPprimer employs the widely used primer design program Primer3 [Rozen, et al. 2000] and the primer specificity evaluation program MFEprimer [Qu, et al. 2009] to design and evaluate the candidate primers based on genomic or transcript DNA database, followed by careful examination to avoid primer dimerization. The graph-expanding algorithm derived from the greedy algorithm was used to determine the optimal primer set combinations (PSCs) for multiplex PCR. In addition, MPprimer provides a virtual electrophotogram to help users choose the best PSC. In short, MPprimer is a valuable tool for designing specific, no dimer formation and amplicons size constrained PSCs to improve the multiplex PCR experiments.