Applying highly polymorphic variable number of tandem repeats loci genetic markers to identity testing

The detection of alleles of variable number of tandem repeats (VNTR) loci by restriction fragment length polymorphism analysis has become an important aspect of genetic characterization for identity testing. Some VNTR loci are so polymorphic that the analysis of three to five genetic markers could potentially provide unique identity. However, the more informative a genetic marker is (i.e., high degree of polymorphisms), the better it is as an exculpatory tool. This approach currently provides the best avenue for excluding a falsely associated individual with a particular sample. When an analysis fails to exclude an individual as the source of the questioned material, a value (frequency of occurrence) should be placed on the VNTR profiles to assess weight to the inclusion in identity testing. Arbitrarily defined fixed bins were designed to accommodate quasi-continuous data and to provide a result that would not place an underestimation of the frequency of occurrence of a set of alleles attributed to an individual.