ISSN: 0022-1198
CODEN: JFSCA
Page Count: 12

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
Nadano, D
Forensic biologists, Fukui Medical School,

Takeshita, H
Forensic biologists, Fukui Medical School,

Kishi, K
Forensic biologists, Fukui Medical School,

Sawazaki, K
Section head of forensic serology, Scientific Investigation Laboratory, Fukui Prefectural Police Headquarters,

Uchide, K
Lecturer, School of Medicine, Kanazawa University,

Iida, R
Forensic biologists, Fukui Medical School,

Yasuda, T
Forensic biologists, Fukui Medical School,

(Received 26 October 1992; accepted 22 January 1993)

Abstract

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 biologists as a genetic marker. We have already reported that human DNase I isozyme patterns from different subjects are classificable into ten groups. 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. Pretreatment of semen samples with neuraminidase enhanced the isozyme band resolution and sensitivity. Activity detection using the dried agarose film overlay (DAFO) procedure was reliable, sensitive and simple, with high resolution, and the phenotypes of DNase I were determined in semen stains of about 0.3 µL stored at room temperature for up to a year in most of the samples tested. The DNase I types in semen stains were correlated with the types found in the corresponding blood and urine samples, although most of the vaginal fluid samples had no typable DNase I activity. This is considerably advantageous for seminal individualization from body fluid mixture stains in criminal cases. An evaluation of DNase I typing by IEF-PAGE and DAFO was also performed on casework samples submitted to our laboratory, and the results showed that DNase I was expected to be one of the most useful individualization marker of semen in practical application.

Keywords:
criminalistics, deoxyribonuclease I (DNase I), dried agarose film overlay (DAFO) method, isoelectric focusing, semen identification, single radial enzyme diffusion (SRED) method, vaginal fluid

Paper ID: JFS13507J
DOI: 10.1520/JFS13507J
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