Recent advances in fluorescent dyes, methods, instruments and software for DNA melting analysis have created versatile new tools for variant scanning and genotyping. High resolution melting analysis (HRM or HRMA) is faster, simpler, and less expensive than alternative approaches requiring separations or labeled probes. With the addition of a saturating dye before PCR followed by rapid melting analysis of the PCR products, the sensitivity of heterozygote scanning approaches 100%. Specificity can be increased by identifying common polymorphisms with small amplicon melting, unlabeled probes or snapback primers to decrease the sequencing burden. However, some homozygotes require mixing for identification. Furthermore, different heterozygotes may produce melting curves so similar to each other that, although they clearly vary front homozygous variants, they are not differentiated from each other. Nevertheless, the experimental return for minimal effort is great. This focus issue of Human Mutation includes a concise, timely review on high resolution melting, a comparison to denaturing gradient gel electrophoresis, integration with qPCR for copy number assessment, combined amplicon scanning and unlabeled probe genotyping from a single melting curve, and applications to the mitochondrial genome and to BRCA1. Hum Mutat 30, 857-859, 2009. (C) 2009 Wiley-Liss, Inc.
