Familiarity with mouse chromosomes is warranted because of the pivotal role of the mouse as an experimental organism and its importance in comparative karyotyping which serves to assist in the identification and mapping of human genes.
Kit 5, Mouse Chromosome Studies, is designed to introduce students to the basic principles entailed in the manipulation of mammalian cells so that chromosomes may be readily visualized, identified and studied. As mouse cells are cultured, their karyotype becomes varied due to an accumulation of translocations and other structural aberrations. Hence the cells in this kit provide a unique opportunity for the students to identify different structural aberrations and try to explain their origins.
Fixed swollen cells arrested in metaphase are provided for student use. The student will affix the cells to microscope slides and stain. These slides are scanned for good chromosome spreads which are observed at high magnification. Students search for normal and aberrant chromosomes, identifying the position of the centromere and relative sizes of chromosome arms.
The manual provided will describe how the cells were prepared for karyotyping, and subsequent steps exercised by the students. It also describes chromosome structure and structural aberrations.

• Enough materials for 30 students working individually.
• 15 tubes each containing metaphase-blocked mouse cell suspension, fixed in acetic acid-methanol fixative.
• Stain #1 and Stain #2; Permount (mounting medium).
• Printed background and procedural information as well as a Glossary of Terms, References, & Further Reading.

Teacher's Preparation

1. Binocular or monocular microscopes - magnification of 400X to 1000X (oil immersion) will enable the students to identify and count chromosomes ans see sister chromatids.
2. Pipettes, microscope slides, coverslips.
3. Staining jars or beakers ( = 250ml) containing room temperature water.

Time Requirements
40-60 minutes.