where a gene can be found on chromosome

Genes are found on chromosomes, specifically on the arms of chromosomes which are divided into a short arm (p arm) and a long arm (q arm). These genes are located in the euchromatin region of the chromosome arms, which is the loosely packed area that allows access for transcription and protein formation. Genes are not located in the telomeres, centromeres, or heterochromatin regions, as those regions are either non-coding or too tightly packed for gene expression. The exact position of a gene on a chromosome is called its locus, which can be described with a code like "3p22.1" indicating chromosome number 3, short arm (p), region 2, band 2, and sub-band 1.