A DNA profile is a set of numbers that represent regions, or loci, of variable, repeated DNA sequences. Short sequences of DNA that repeat a number of times are known as short tandem repeats (STRs). The number of times a sequence repeats varies from person to person and, except in the case of identical twins, this variability can be used to tell people apart. STR analysis is a forensic technique that develops and distinguishes DNA profiles by evaluating these regions.