ALLELE FREQUENCIES OF 9 STR SYSTEMS IN THE FLEMISH POPULATION AND APPLICATION IN PARENTAGE TESTING

In order to apply a set of nine STR loci in parentage testing, we per formed a population genetic study on a sample of the Flemish populatio n. Genotypes for HUMHPRTB, HUMFABP, HUMCD4, HUMCSF1PO, HUMTH01, HUMPLA 2A, HUMPLA2A1, HUMF13A01, HUMCYAR04 and HUMLIPOL were determined using three tripler PCR reactions and silver staining. Allele frequencies s howed no deviation from Hardy-Weinberg equilibrium. The frequency dist ribution agreed well with other Caucasian populations but three interm ediate fragments, not previously found in Caucasians, were observed. W e then resolved a series of 151 parentage disputes of which 103 were e xclusions. In six cases, evidence for exclusion was obtained by only o ne informative STR locus out of eight for male children or out of nine for female children. These exclusions were confirmed with additional polymorphic markers. In one case of inclusion, a paternal allele expan ded with one repeat unit of HUMHPRTB. This observation illustrates tha t STRs do not differ from other genetic systems in the fact that more than one excluding locus is required before exclusion is demonstrated.