FISH - Fluorescence in SITU Hybridization
FISH is a technique used to visualize genes on various targets using fluorescence microscope. Such targets include metaphase chromosomes (the classical chromosomes), stretched chromosomes, interphase nuclei or DNA fibers. In short FISH is a technique to show where a gene is located.
FISH is a Technique to Map Genes
FISH provides the most direct technique to demonstrate the location of a gene of interest. Using metaphase chromosomes, one can determine the chromosomal localization of a gene. This tells in which chromosome and which specific region of a chromosome the gene is located, providing the basic information which serves as a stepping stone for more precise localization needs.
For more precise mapping, chromosomes can be stretched, using centrifugation techniques, for example. This provides a 10 to 15 fold increase in resolution. This means that two genes that are more than 200,000 base pairs apart can be visualized as distinct signals.
The highest resolution is achieved using DNA fibers, prepared by spreading DNA on a microscope slide much in the same way as blood smears are prepared in the clinical laboratory. Using modern signal enhancement techniques, probes of only a few hundred base pairs in size cab be visualized and localized with high accuracy.
What can FISH be used for?
FISH is a well-established technique to detect Chromosomal Abnormalities such as in cancer cells, as well as in some genetic disorders like Down Syndrome. The precision and exact nature of the technique makes FISH an important research tool. A typical example of FISH application is a demonstration of loss or gain of genetic material in cancer cells (amplification of oncogenes, deletions of chromosomal regions).
The laboratory is equipped with a Leica DM Fluorescence Microscope, a CCD Camera Connected to a PC Computer. The equipment is operated using VYSIS Software. The new equipment and the new crew in the core provide a unique setting for high-resolution mapping of disease genes.
The FISH Core will be used by researchers who need to localize gene sequences in genomes of human or model organisms. Thus, the unit will serve not only the Department of Human Genetics in the Gonda Building but also other research groups of the UCLA Campus.
For more information, contact:
York Marahrens Office: 4557A Gonda Phone: 310-794-5948 Fax: 310-794-5446