In situ hybridization (ISH) takes advantage of the ability of mRNA within a cell to hybridize with exogenously applied complementary RNA (riboprobes) or DNA molecules. This interaction is visualized by labeling the applied nucleic acid probe with a detectable molecule (radioactive, such as 35 S, or non-radioactive, such as digoxygenin [DIG]). The technique allows patterns of gene expression to be visualized in many tissues or cell types simultaneously.
