IG1_21

CODIS (Combined DNA Index System) Microsatellite loci

The standard human DNA forensic testing set used by the FBI and RCMP comprises 13 microsatellite loci [dark grey boxes] located on separate chromosome. The observed range of variation at these loci is sufficient that the probability of any two individuals showing the same pattern at all 13 loci is <1 / 10¹⁵, more than five orders-of-magnitude less than current human population of 6 x 10⁹. The CODIS set does not include markers for the X- and Y-chromosomes, which are typed separately. The original CODIS set was developed as an autoradiogram test. An alternative Second Generation Multiplex (SGM) set was developed by Applied Biosystems (ABI) for use with its automated fluorescent DNA sequencers. The two sets are now used in tandem [blue boxes].