High-Resolution FISH Analysis Using DNA Fibers Generated by Molecular Combing

Molecular combing is a technique used to stretch hundreds of consistent DNA molecules in parallel on a glass surface, with a resolution of two kilo-basepairs per micrometer. The combination of this approach with fluorescent in situ hybridization (FISH) has enabled the direct visualization of DNA structure and variations at an unprecedent high resolution. This technique has been successfully used in various studies such as the identification of copy number and genomic structural variations and the precise measurements of overlap and gap sizing between contigs in genome assemblies. Here, we describe the procedure for the preparation of DNA fibers by molecular combing and its applications in multicolor fiber-FISH.