This script eliminates from consideration as putative source populations,
those populations for which the individual has too many private alleles. The
populations that remain are putative source populations, subject to further
consideration.
The algorithm identifies those target populations for which the individual
has no private alleles or for which the number of private alleles does not
exceed a user specified threshold.
An excessive count of private alleles is an indication that the unknown does
not belong to a target population (provided that the sample size is
adequate, say >=10).