The PCR-amplifiable markers in this database are classified by the type of tandem nucleotide repeat as di-, tri-, tetra-, mixed, or other. All of the di-, tri-, and tetra-nucleotide repeats contain one or more uninterrupted tandem repeats, in which each tandem repeat contains at least five di-, tri-, or tetra-nucleotide repeat units (e.g., [CA]5, [CAT]5, [CATA]5) within the amplified sequence. Markers listed as "mixed" contain two or more tandem repeat units of different types (e.g., di- and tri-; di- and tetra-; or tri- and tetra-). All markers not listed as di-, tri-, tetra-, or mixed are classified as "other". "Other" repeats include large repeats (6-20mers, e.g., [CATTTATGAT]5), broken or imperfect repeats, stretches of single nucleotides, or unspecified repeats. An explanation for each marker in the "other" category is given in the "notes" section of the "Information about the marker" page.