Genetic markers are points of variation in DNA that scientists can use to decode and interpret information about the source of the DNA. These markers act as genetic “bookmarks,” allowing scientists to quickly determine genetic characteristics associated with the marker’s location (locus) on the DNA strand. There are 21 genetic markers GTL commonly uses in determining parentage, which include : amelogenin, CSF1PO, D13S317, D16S539, D18S51, D21S11, D3S1358, D5S818, D7S820, D8S1179, FGA, PENTA_D, PENTA_E, TH01, TPOX and VWA amongst others.