Cytogenetic Techniques for Myeloid Disorders

Chromosomes are prepared from dividing cells (mitoses), as at metaphase, just before division, they shorten and become recognizable, discrete units. The cells are arrested and accumulated in metaphase or prometaphase by destroying (e.g., with colcemid) the mitotic spindle which would separate the chromatids. The cells are treated with a hypotonic solution to encourage spreading of the chromosomes. They are then fixed, after which they can be stored indefinitely. Fixed cells are spread on slides and air-dried. They can be stained immediately, but are usually first treated to induce banding patterns on the chromosomes to assist in their identification.