ABSTRACT
To introduce a duplex PCR system consisting of the STR loci D21S11 and HUMFIBRA in forensic identity testing we analysed a Dutch Caucasian database of 205 individuals. The combined power of discrimination of the two loci is 0.9978 and there was no evidence for linkage equilibrium between the two loci (p = 0.91). However, we noticed departure from Hardy-Weinberg equilibrium for the D21S11-locus in our database (p = 0.03), but the differences between observed and expected D21S11 allele pair frequencies were of negligible practical significance in forensic calculations.
Subject(s)
Ethnicity/genetics , Genetic Markers/genetics , Polymerase Chain Reaction/methods , Repetitive Sequences, Nucleic Acid/genetics , Alleles , Chromosome Mapping , Gene Frequency/genetics , Genetics, Population , Genotype , Humans , Linkage Disequilibrium , NetherlandsABSTRACT
A series of experiments has been performed to evaluate amplification and typing of the D1S80 VNTR locus. The validation study that has been carried out showed that correct D1S80 typing results can be obtained when a defined amplification protocol and a high-resolution polyacrylamide gel electrophoresis method are used. The use of the Chelex extraction protocol has substantially reduced the processing time. DNA-extraction, amplification and subsequent typing can be performed in one day. The discrimination power of this locus is 0.94 in a Dutch Caucasian population sample. The system is extremely sensitive: 0.1 ng of genomic DNA gave a correct typing result. The test could also detect the correct genotypes in mixed samples containing DNA from different individuals. Even if the major type was in a 20-fold excess, the minority type could still be amplified and typed correctly. We have found no deviation from Hardy-Weinberg equilibrium in a Dutch Caucasian population sample. Evidence for the somatic stability of this locus was obtained from a set of experiments where we compared DNA-profiles from corresponding blood, semen and saliva samples. The results of this study suggest that in the near future analysis of the D1S80 locus by DNA-amplification can be applied in actual forensic case work.
