Definition of Chromosome banding

Chromosome banding: The treatment of chromosomes to reveal characteristic patterns of horizontal bands like bar codes.

The banding patterns lend each chromosome a distinctive appearance so the 22 pairs of human nonsex chromosomes and the X and Y chromosomes can be identified and distinguished without ambiguity. Banding also permits the recognition of chromosome deletions (lost segments), chromosome duplications (surplus segments) and other types of structural rearrangements of chromosomes.