define genetic markers
Chicks atop a picture of a genetic map of a chicken. A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. It can be described as a variation (which may arise due to mutation or alteration in the genomic loci) that can be observed.
CHEMICAL AND MOLECULAR MARKERS. A genetic marker is any visible character or otherwise assayable phenotype, for which. alleles at individual loci segregate in a Mendelian manner. Genetic markers can be used to. study the genetics of organisms, including trees, at the level of single genes. The develop-. ment of the discipline of genetics would not have been possible without genetic markers. such as the visible characters in peas and Drosophila.