A DNA marker is a variation in the DNA code, mapped to a specific location in the genome. DNA markers can be genotyped and may be associated with one or more physical characteristics.
Are all DNA markers alike?
Markers can differ in mode of inheritance, physical size (number of base pairs), functionality and how they are applied in genetic improvement. The prevailing type of marker now being used in DNA testing for traits is known as a single nucleotide polymorphism (SNP). SNP markers vary at a single base location in the genome, creating two different alleles (or forms) of the marker.