Molecular Markers, also known as genetic markers, are pieces of DNA that can be associated with a certain location within a genome.1 Molecular markers are used to identify particular sequences of DNA that enable the identification of a certain species. In the context of invasive ecology. According to Bossdorf 2005, molecular markers can be used to quantify the amount of genetic variation that is being introduced and the pathway of natural selection an invasive species underwent.2
2Bossdorf, Oliver, Harald Auge, Lucile Lafuma, William E. Rogers, Evan Siemann, and Daniel Prati. "Phenotypic and Genetic Differentiation between Native and Introduced Plant Populations." Oecologia 144.1 (2005): 1-11. Web.