genetic marker
(jeh-NEH-tik MAR-ker)
A sequence of DNA with a known physical location on a chromosome. Genetic markers and genes that are close to each other on a chromosome tend to be inherited together. Genetic markers vary between individuals to the extent that they can be used to help find a nearby gene causing a certain disease or trait within a family. Examples of genetic markers are single polymorphism nucleotides (SNPs), restriction fragment length polymorphisms (RFLPs), variable number of tandem repeats (VNTRs), microsatellites, and copy number variants (CNVs). Genetic markers may or may not have a known function.