Spectral Karyotyping. SKY is a technique that allows for the visualization of all of an organism's chromosomes together, each labeled with a different color. This is achieved by using chromosome-specific, single-stranded DNA probes (each labeled with a different fluorophore) to hybridize or bind to the chromosomes of a cell; resulting in each chromosome being painted a different color. This technique is useful for identifying chromosome abnormalities because it is easy to spot instances where a chromosome painted in one color has a small piece of another chromosome, painted in a different color, attached to it. (Also see FISH, CGH.)