Short Tandem Repeats Str
Multiple copies of an identical (or similar) DNA sequence arranged in direct succession where the repeat sequence unit is 2 base pairs (bp) to 6 bp in length; because STRs generally occur in the DNA outside of the constraints (i.e., selective pressure) of genes, the number of repeat units can vary between individuals;2 variations in STRs may be used for distinguishing individuals, and in biological relationship and ancestry testing