Molecular hybridisation

Molecular hybridisation is a technique used to identify a nucleic acid sequence such as locating a locus on a chromosome within a cell or tissue. It is based on the principle of complementarity between nucleic acid bases, particularly between DNA and the complementary RNA strand sequence.
The complementary strand sequence is also called the probe and is generally "labelled" to locate it. There are "radioactive" probes and "cold" probes.