STR stands for short tandem repeat, and the method relies on the variability in the STRs that are scattered along the human chromosomes to distinguish the DNAs of different individuals. The FBI uses a standard set of probes that bind to 13 specific STR regions to generate DNA profiles. The odds that any two humans (except identical twins) will have a match at all 13 loci is about one in a billion. See CODIS, DNA fingerprint technique, microsatellites, repetitious DNA.
Subjects: Genetics and Genomics.