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Chromosome Classification via Karyotyping
Molecular Biology 5
(v1 as of 1/8/06)
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Magnified in the light microscope, the rod-like chromosomes within one cell vary considerably in size as shown in the metaphase spread photographed via light microscopy after staining with Giemsa stain to show characteristic banding patterns. A karyotype shows each homologous pair for each chromosome number (i.e., the chromosome from the mother, and the chromosome from the father). 

Remember that by the time these chromosomes were photographed, the DNA had duplicated. The sister chromatids are present but are closely attached so that a chromatid pair shows as only one strand.
Metaphase chromosome spread... can you match the homologous pairs?
(see below for the answer)


 
Figure 1
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Metaphase chromosomes after karyotyping. 
(ref: Murdoch)

Figure 2.

The chromosomes from the first photograph were organized by finding the homologous pair and then placed in an order in terms of size with chromosome 1 being the largest and 22 the smallest, excluding X and Y.

As you can see above (Figure 2), this is a karyotype from a human male.  A karyotype for a female would have two X chromosomes and no Y chromosome.  The "shadow" around some of the chromosomes reflects the fact that the original photograph above was cut up with scissors and rearranged manually.  The "shadow" is simply the cut edge of the piece cut from the large photo. (Figure 1) This manual work can now be done via computer.

For a real shot at karyotyping or to see more karyotypes, visit the following University of Washington websites: 
The Cytogenetics Gallery (very good)
Karyotyping Activity
 
References: 
Images: Metaphase spread photo and karyotype source: http://murdoch.rch.unimelb.edu.au/cyto.htm
Suggested readings, viewings 
or experieinces:
The Cytogenetics Gallery (very good)
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