Talking Glossary of Genetic Terms
In Situ Hybridization
In situ hybridization is a laboratory technique in which a single-stranded DNA or RNA sequence called a probe is allowed to form complementary base pairs with DNA or RNA present in a tissue or chromosome sample. The probe has a chemical or radioactive label attached to it so that its binding can be observed.
In situ hybridization. "In situ" is a Latin term for "in place", and then it's used in this context for detecting either RNA or DNA in the situation of the actual animal or the cells. It's a laboratory technique where it uses a probe, and this probe is usually made with DNA or RNA. It's single-stranded and it has some sort of moiety that you can detect either chemically or radioactively, and then that single-stranded is hybridized, and that's where the hybridization part comes in. You mix this probe in with your tissue sample, and you look for the single-stranded to bind in situ to the expressed mRNA or the DNA that you're looking for. You wash away the unbound probe, and then you look for where that gene is being expressed or where that piece of DNA is in the cell. This is a way of detecting things in sort of three-dimensional space, which is often very important for scientists to know where things are expressed both in terms of time and space.
Name: Shawn Burgess, Ph.D.
Occupation: Senior Investigator, Genome Technology Branch; Head, Developmental Genomics Section
Biography: Dr. Burgess's laboratory studies developmental processes and their relation to human genetic disease. His group employs a variety of modern molecular biology methods to identify and functionally characterize novel developmental genes involved in organogenesis of the ear and maintenance of stem cell populations. Before coming to the National Human Genome Research Institute (NHGRI), Dr. Burgess was part of a group at the Massachusetts Institute of Technology that pioneered the use of pseudotyped retroviruses for mutagenesis in zebrafish. This technology represented a major breakthrough in the ability to quickly identify genes important in the early development of vertebrates.