Abstract
DNA was isolated from casework urine samples previously submitted for toxicological analysis. The quality and quantity of DNA isolated was determined by spectrofluorometry and agarose yield gel electrophoresis. Hae III restricted samples were then resolved by analytical agarose gel electrophoresis, transferred to a membrane by Southern blotting and hybridized with a chemiluminescently-labelled (D2S44) probe. The DNA fragment banding patterns were indistinguishable from the DNA banding patterns of blood specimens collected from the same donor. Only 5 of 20 samples yielded banding patterns and the banding intensity relative to background was low. Genomic DNA was also obtained from casework samples by Chelex extraction, amplified by polymerase chain reaction (PCR) and then genotyped for human leucocyte antigen (HLA) DQα. Of 20 specimens, 13 (65%) were typed correctly producing identical results for urine and blood specimens obtained from the same donor. Aging studies of casework samples and normal samples (from a non-drug using population) were also conducted with PCR-HLA DQα analysis. Results of these studies indicate that amplification by PCR was more likely to produce positive results. Based on these findings, we conclude that PCR-initiated analysis is more suitable than RFLP analysis for individualization of urine samples.
