noun, plural: marker genes
(genetics) A gene with known physical location, easily detectable phenotype, and whose pattern of inheritance can be followed.
These markers are used to trace or identify specific region of a gene (especially one that is associated with an inherited disease) on a particular chromosome. These markers can be an enzymatic reporter gene, a selectable marker conferring antibiotic resistance or a cell membrane protein with a characteristic epitope.
Also called: genetic marker, DNA marker.
See also: genetic map.