Generation of Inexpensive, Highly Labeled Probes for Fluorescence In Situ Hybridization (FISH)

DNA-FISH remains the method of choice to visualize genomic regions in situ ranging from a single locus to entire chromosomes. Current methods to generate probes rely on expensive kits that vary in labeling efficiency and are limited by the size and/or amount of starting material and by the choice of fluorophores. Here we describe a protocol to prepare inexpensive ($20) DNA-FISH probes using an isothermal polymerase, incorporating labeled nucleotides while amplifying minute amounts of any template (PCR fragments/BAC/YAC/fosmids). For complete details on the use and execution of this protocol, please refer to Grosmaire et al. (2019) and Sharma et al. (2014).