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Human Chromosome Preparatio (chromosome) (chromosomes)
Human Chromosome Preparation and Karyotyping

Every high school student can capture a "bit of immortality" through a laboratory experience normally reserved for higher level biology classes in college. During this chromosome lab, the students prepare, develop and stain their own chromosomes. The metaphase spread is photographed and the students then do the karyotyping of their own chromosomes (Coburn & Leygauf 1976). This lab is guarenteed to generate enthusiasm and interest. Students will get a feeling of accomplishment and excitement over the numerous, but simple steps that are required.

A note of caution: this lab requires the withdrawal of blood from the arm by a qualified individual. Each student must have a permission slip signed by a parent or guardian.

Students must return these signed slips before their blood can be withdrawn. Local hospitals are usually more than willing to supply the equipment and personnel for the blood withdrawal.

The overview of the lab procedure is rather straightforward. A blood sample is taken and white blood cells grown in a special medium for three days under the influence of the mitotic stimulant, phytohemaglutinin. After 72 hours, Colcemid®, a chemical that inhibits spindle formation, is added. The red blood cells are exploded with a hypotonic solution of potassium chloride. The remaining swollen white blood cells are fixed with alcohol and acetic acid. The resulting cells are dropped from a pasteur pipette onto a clean slide, causing the cells to splatter and separate. When the slide is stained with giemsa stain, the chromosomes of the individual white blood cells are visible (Macgregor & Narley 1983).

New page showing sister chromosome exchanges.


Ordered from GIBCO/BRL, per class: GIBCO phone number is 1-800-828-6686