What is in situ hybridization?

In situ hybridization (ISH) is a type of molecular biology technique used to detect the presence or absence of specific DNA or RNA sequences in cells or tissues. It involves using a labeled complementary DNA or RNA strand (a probe) to hybridize with the sequence of interest within the cell or tissue. The probe is labeled with a fluorescent dye or enzyme, allowing visualization of the location of the target sequence under a microscope. It is commonly used in research and diagnostics to study gene expression, identify infectious agents, and detect chromosomal abnormalities.