Nucleic acid hybridization is a method where single-stranded nucleic acids, such as DNA or RNA, interact to form complexes known as hybrids. These hybrids are created from molecules with similar and complementary sequences. This process helps determine the degree of sequence similarity between nucleic acids and can be used to identify specific sequences within them. Hybridization can occur in a solution or when one component is immobilized on a gel, or more commonly, on nitrocellulose paper.There are several ways to detect hybrids, such as visualizing them with an electron microscope, using radioactively labeled components and removing non-complexed DNA, or employing enzyme digestion that targets single-stranded nucleic acids, followed by measuring the bound radioactivity. Hybridizations can be performed in various combinations: DNA-DNA (with DNA made single-stranded through heat denaturation), DNA-RNA, or RNA-RNA.In situ hybridization involves using a labeled nucleic acid, often tagged with a fluorescent dye, to target appropriately prepared cells or tissue sections. This technique is particularly useful for detecting specific sequences or locating genes on particular chromosomes through fluorescent in situ hybridization (FISH) analysis.
