The Karyotype reference article from the English Wikipedia on 24-Jul-2004
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Karyotype

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Karyogram of human femaleEnlarge

Karyogram of human female

A karyotype is the complete set of all chromosomes of a cell. The chromosomes are arranged and displayed (often on a photo) in a standard format: in pairs, ordered by size. Karyotypes are examined in searches for chromosomal aberrations, and may be used to determine other macroscopically visible aspects of an individual's genotype, such as sex (XX vs. XY pair).

Classic karyotype

In the "classic" (depicted) karyotype, a dye, often Giemsa, is used to make bands on the chromosomes visible. This is also referred to as G-banding.

Spectral karyotype

In this newer technique, several different probes, carrying different amounts of a fluorescent dye, give each chromosome pair unique spectral characteristics, which can be automatically identified through an interferometer and a computer.