DYS389 is a special marker that has two different values at the same location.

The two values are designated "DYS389I" and "DYS389B". Typical values would be "DYS389I=13" and "DYS389B=16".

However, DYS389 is different from other markers in that the sum of the values for DYS389I and DYS389B is also designated "DYS389II"

For Example, if DYS389I=13 and DYS389B=16, then DYS389II=29.

SMGF maintains that using DYS389I and DYS389B will give more accurate matches and TMRCA calculations. Consequently, if you choose SMGF (or Genographic) as the Search page lab standard, you may enter values for these markers directly.