FISH (fluorescence in situ hybridization) also called whole chromosome painting is a new technology that allows chromosome abnormalities associated with many diseases to be detected more rapidly and accurately. One of the abnormalities the technology can detect is an exchange of material between chromosomes. A normal chromosome seven is shown with red stain (far right). To its left, chromosome seven has a green tip at the top indicating the presence of material from chromosome 12. Similarly, the lowest green-colored chromosome is a normal chromosome 12 while the top green-colored chromosome has a red piece of chromosome seven.