An identifiable segment of DNA (e.g., Single Nucleotide Polymorphism [SNP], Restriction Fragment Length Polymorphism [RFLP], Variable Number of Tandem Repeats [VNTR], microsatellite) with enough variation between individuals that its inheritance and co-inheritance with alleles of a given gene can be traced; used in linkage analysis. or A specific sequence of DNA at a known location on a chromosome. There are many genetic markers on each chromosome. Genetic markers and genes that are close to each other on a chromosome are usually inherited (passed from parent to child) together. This may help researchers find a gene near a marker that may cause a certain disease or trait within a family. Examples of genetic markers are single polymorphism nucleotides (SNPs) and microsatellites.