The word chromosome is derived from the Greek words chromos, meaning color, and soma, meaning body. In meiosis and mitosis our genetic material is condensed into chromosomes that are visible in the microscope after fixation and staining. The subfield of genetics that study the chromosomes and chromosomal aberrations are called cytogenetics.

Each chromosome has a unique banding pattern that is used for its identification and for the detection of potential structural abnormalities. The chromosome banding pattern is comprised of alternating light and dark bands, that appear along its length after being digested with an enzyme (trypsin) stained with a dye (Giemsa or Leishman).