Description of the Chromosome

When we want to describe the location of some structural abnormality or the location os some specific region (e.g. gene locus) we use special marks. We have to count the regions always from the centromere – for both arms.

Example: 1q13



 * the first number is the number of chromosome – chromosome 1;
 * (p) and (q) are used for the marking of arm – (p) for small arm and (q) for long arm – the long arm;
 * the third number is for the region of chromosome – region 1;
 * last number is for the band – band 3.

So the change is located on the long arm of chromosome 1 (see Fig. Chromosomal marking).

Related articles

 * Chromosome Abnormalities
 * Eukaryotic Chromosomes