Chromosome regions

The Chromosome region p is a virtual region that exists in all chromosomes.

During the phenomenon of cell division, the molecules that compose chromosomes (DNA and proteins) suffer a condensation process (called the chromatin condensation), and forms a compact and small complex. In diploid organisms, homologous chromosomes get attached to each other by the centromere. The centromere divides each chromosome into two regions: the smaller one, which is the p region, and the bigger one, the q region.

Usually, as a convention, the p region is represented in the upper part of an image while the q region is in the bottom part.