An idiogram (conceptual sign ) is the schematic graphic representation of the banding of the chromosomes of the haploid chromosome set or karyotype .
The term idiogram should not be confused with the term ideogram (a character that represents a specific object).
In idiograms, the dark areas always represent G-bands. The white areas represent the R-bands which do not accept the Giemsa dye . Areas made up of repetitive elements are sometimes shown hatched.
Idiograms are provided with standardized names for these chromosomal regions (banding). In humans, this designation is made up of the following elements: number or letter of the chromosome, p or q for the respective arm (p for petit), as well as numbers that count up from the centromere. For a finer distinction, the numbers can have several places. The figure shows the Y chromosome. The band Yp11.31 is therefore a sub-band of Yp11. The term “Yp” stands for the entire short arm of the Y chromosome. Centromere regions are also denoted by c (Yc). For the sake of simplicity, telomer areas are often referred to as tel (e.g. Yptel or Yqtel) and areas close to telomer as ter (Ypter).
- Karyogram (photographic representation)
- Nenno, M. (1998): Characterization of the polytene chromosomes from the embryosuspensor of Phaseolus coccineus L. Zugl. Diss. Univ. Kaiserslautern, URL: http://kluedo.ub.uni-kl.de/volltexte/2000/7/html/diss21c.htm (image below)
- UC Davis Veterinary Genetics Laboratory, URL: http://www.vgl.ucdavis.edu/services/idiogram.php