A genetic marker is the gene or DNA sequence with a known location on the chromosome that can be used to identify individuals or species. It can be described as a variation which may occur due to mutation or alteration in the genomic loci that can be observed. A genetic marker may be a short DNA sequence, such(a) as a sequence surrounding a single base-pair change single nucleotide polymorphism, SNP, or a long one, like minisatellites.
For numerous years, gene mapping was limited to identifying organisms by traditional phenotypes markers. This sent genes that encoded easily observable characteristics such(a) as blood rank or seed shapes. The insufficient number of these race of characteristics in several organisms limited the mapping efforts that could be done. This prompted the development of gene markers which could identify genetic characteristics that are non readily observable in organisms such(a) as protein variation.