
CODIS (Combined DNA
Index System)
Microsatellite loci
The standard human DNA forensic testing set used
by the FBI and RCMP comprises 13
loci [boxes in grey and blue], all but two of
which are located on separate chromosomes. 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 microsatellite
loci on the X- and Y-chromosomes, which
are typed simply by X- and Y-specific
markers.