DEOXYRIBONUCLEASE-I (DNASE-I) TYPING FROM SEMEN STAINS - LOW ENZYME-ACTIVITY IN VAGINAL FLUIDS DOES NOT INTERFERE WITH SEMINAL DNASE-I TYPING FROM MIXTURE STAINS
K. Sawazaki et al., DEOXYRIBONUCLEASE-I (DNASE-I) TYPING FROM SEMEN STAINS - LOW ENZYME-ACTIVITY IN VAGINAL FLUIDS DOES NOT INTERFERE WITH SEMINAL DNASE-I TYPING FROM MIXTURE STAINS, Journal of forensic sciences, 38(5), 1993, pp. 1051-1062
We describe the use of deoxyribonuclease I (DNase I) polymorphism for
individualization of semen in body fluid stain mixtures, as a means of
providing new and more useful information to practicing forensic biol
ogists as a genetic marker. We have already reported that human DNase
I isozyme patterns from different subjects are classifiable into ten g
roups. Isoelectric focusing of DNase I isozymes on polyacrylamide gel
(IEF-PAGE, pH 3.5 to 5) was accomplished using a 0.5 mm thick gel. Pre
treatment of semen samples with neuraminidase enhanced the isozyme ban
d resolution and sensitivity. Activity detection using the dried agaro
se film overlay (DAFO) procedure was reliable, sensitive and simple, w
ith high resolution, and the phenotypes of DNase I were determined in
semen stains of about 0.3 muL stored at room temperature for up to a y
ear in most of the samples tested. The Dnase I types in semen stains w
ere correlated with the types found in the corresponding blood and uri
ne samples, although most of the vaginal fluid samples had no typable
DNase I activity. This is considerably advantageous for seminal indivi
dualization from body fluid mixture stains in criminal cases. An evalu
ation of DNase I typing by IEF-PAGE and DAFO was also performed on cas
ework samples submitted to our laboratory, and the results showed that
DNase I was expected to be one of the most useful individualization m
arker of semen in practical application.