Chromosome regions

Several chromosome regions have been defined by convenience and convention in order to talk about gene loci.

Named regions include: During cell division, the molecules that compose chromosomes (DNA and proteins) undergo a condensation process (called the chromatin reticulum condensation) that forms a compact and small complex called a chromatid.

The complexes containing the duplicated DNA molecules, the sister chromatids,[2] are attached to each other by the centromere(where the Kinetochore assembles).

Whereas if the chromosome is isobrachial (centromere at centre and arms of equal length), the p and q system is meaningless.

The telomere has repetitive junk DNA and hence any enzymatic damage will not affect the coded regions.

Chromosome structure.
A typical chromosome with its structures. Often, the centromere has a three layered covering known as Kinetochore.
Diagram of a duplicated and condensed ( metaphase ) eukaryotic chromosome. (1) Chromatid – one of the two identical parts of the chromosome after S phase . (2) Centromere – the point where the two chromatids touch, and where the microtubules attach. (3) Short arm ( p ). (4) Long arm ( q ).
Regions of a chromosome