Before revision: Chromosome components :(1) Chromatid(2) Centromere(3) Short (p) arm(4) Long (q) arm A locus (plural loci) in genetics is a fixed position on a chromosome , like the position of a gene or a marker (genetic marker ) .
After revision: Parts of a typical chromosome :(1) Chromatid(2) Centromere(3) Short (p) arm(4) Long (q) arm In genetics, a locus (plural loci) is a specific, fixed position on a chromosome where a particular gene or genetic marker is located .