What are Molecular Markers?

A marker, in this context, is an identifier (sometimes called a “tag”) of a particular aspect of phenotype and/or genotype; its inheritance can easily be followed from generation to generation.

Markers can be:

Morphological: phenotypic variation which is scorable on the basis of a single plants (e.g. flowering time)

Biochemical: variants in the size or net charge of a protein (eg isozymes) or in the chemical composition of a metabolite (e.g. sugar)

Molecular: variants in the DNA sequence (eg microsatellites)