From Khalid Belkhir and Kevin J Dawson:
Partition is a model-based statistical software package for identifying population sub-division (barriers to gene flow) and assigning individuals to populations, on the basis of their genotypes at co-dominant marker loci. Suitable genetic markers include microsatellites and allozymes. Unlinked, or loosely linked, marker loci should be used, so that the assumption of linkage equilibrium is a reasonable one.
The underlying population genetic model is appropriate for out-crossing diploid organisms. It assumes that the individuals in the sample belong to a number of separate source populations. These source populations are assumed to be at Hardy-Weinberg and linkage equilibrium, but the allelic composition of these source populations, and even the number of source populations represented in the sample, are treated as parameters whose values are unknown.