Genetic markers are segments of DNA that serve to identify a certain species or individual. They are specifically a short, easily recognizable portion that is on a known location of a chromosome (Genetic Marker n.d.). When following a specific species or individual, the genetic marker may stay the same or change indicating mutation. Previously, genes that coded for obvious phenotype characteristics were used for this same purpose, but by using pieces of actual DNA, one isn't restricted by the number of easily identifiable characteristics (NFGEL 2006).
To obtain a genetic marker, one extracts DNA or chemicals from an organism and creates a data representation of the indicator (Genetic Marker n.d.). Molecular markers can be either biochemical or molecular. Biochemical markers show the expression of a gene in proteins or amino acid structures. Molecular markers show the variation, or presence of nucleotide sequences (NFGEL 2006).
National Forests Genetic Library (NFGEL). 2006. What is a Genetic Marker? United States Department of Agriculture.
Genetic Marker. In Wikipedia. n.d. Accessed on March 16th, 2015 at http://en.wikipedia.org/wiki/Genetic_marker