Cytogenetics is the field of study devoted to chromosomes, and involves the direct observation of a cell’s chromosomal number and structure, together known as its karyotype. Many chromosomal abnormalities are associated with disease. Each chromosome in a karyotype can be stained with a variety of dyes to give unique banding patterns. More recent techniques, including comparative genomic hybridization and fluorescence in situ hybridization (FISH), allow for detecting specific chromosomal features or abnormalities.

This video will begin by examining the principles of these classical and modern cytogenetics techniques. This is followed by an examination of a general protocol for performing FISH. Finally, several examples of how karyotyping can be applied to various medical applications are presented.