A molecular marker is a molecule contained within a sample taken from an organism or other matter. It can be used to reveal certain characteristics about the respective source. DNA, for example, is a molecular marker containing information about genetic disorders, genealogy and the evolutionary history of life. To develop genetic markers using DNA variants, DNA hybridization or PCR techniques are often used. In DNA hybridization, a short DNA fragment that is homologous to the target DNA is used as a probe. The probe is tagged with a radioisotope and hybridized with the DNA being analyzed.