Hydrolyzing the phosphodiester bond of a single strand of the double helix is known as nicking. Creating nicks in DNA is required for nick translation, a technique used to tag a strand of DNA. In nick translation, labeled deoxynucleotide triphosphates (dNTPs) are incorporated into a single strand of DNA by DNA Polymerase I. These labeled dNTPs are then ligated with the existing strand. These labeled fragments can then be used as probes in fluorescent in situ hybridization.