Ch. Rittner

Application of DNA techniques for identification using human dental pulp as a source of DNA

SummaryDental pulp tissue could be obtained in most cases from materials obtained under experimental conditions and from forensic casework (air accidents, burned and putrefied bodies). Teeth extracted during dental treatment (n = 30) were stored for 6 weeks and 4 years at room temperature. In addition teeth (n = 10) extracted from jaw fragments that had been stored for 15 years at room temperature, and teeth extracted post mortem from actual identification cases (n = 8) were investigated. Following extraction from dental pulp tissue the DNA concentration was measured by fluorometry. The amount of DNA obtained from the dental pulp tissue of a single tooth varied from 6 μg to 50 μg DNA. In most cases high molecular weight DNA was still present although the major portion consisted of degraded DNA. Genomic dot blot hybridization for sex determination using the biotinylated repetitive DNA probe pHY 2.1 was performed and sex was correctly classified in all cases using 50–100 ng target DNA. PCR typing of the HLA-DQα and ApoB 3′ VNTR systems from dental pulp tissue DNA was in agreement with the results obtained from blood, bloodstains, or lung tissue. In addition, Southern blot analysis of selected samples using the single locus VNTR probe pYNH24 was successfully performed. In all cases the DNA recovered from dental pulp was unsuitable for multilocus probe analysis.ZusammenfassungZur Untersuchung gelangten anläßlich einer Zahnbehandlung extrahierte Zähne nach einer Liegezeit bei Raumtemperatur von 6 Wochen (n = 20) bis zu 4 Jahren (n = 10) sowie postmortem extrahierte Zähne von aktuellen Identifikationsfällen (n = 8) und einem Flugzeugabsturz des Jahres 1976 (n = 10). Die Zahnpulpa wurde präpariert und eine DNA Extraktion vorgenommen. Die Ausbeute betrug 6 μg bis 50 μg DNA pro Zahn. In den meisten Fällen war neben degradierter DNA noch hochmolekulare DNA vorhanden. Die Geschlechtsbestimmung erfolgte durch Dot-Hybridisierung mit der biotinylierten repetitiven DNA-Sonde pHY 2.1. In allen Fällen konnte das Geschlecht mit 50–100 ng Ziel-DNA zutreffend bestimmt werden. An genetischen Markern nach DNA-Amplifikation durch PCR erfolgte eine Typisierung der HLA-DQα und ApoB 3′ VNTR Merkmale. Die Resultate zeigten Übereinstimmung mit den Genotypen, die an Blut, Blutspuren oder Lungengewebe ermittelt wurden. Southern Blot-Analysen mit Minisatelliten-DNA-Sonden ergaben auswertbare Resultate mit der Einzellocus-Sonde pYNH24, während eine Multilocus-Sonden-Hybridisierung der aus den Zahnpulpen isolierten DNA nicht gelang.

Use of the software 'Poser4' in reconstruction of accident and crime scenes

The reconstruction of accident and crime scenes demands the full attention of the forensic working physician. Description by words is often difficult and liable to be misunderstood. Reconstruction in the original places of events are expensive and in some cases impossible. Computer graphics and animations give the possibility to construct the original course of events. Poser4 is a software package to perform these reconstructions in an easy and vivid way. We investigated the possibilities of reconstructing an accident with this software.

Application of DNA Polymorphisms in Paternity Testing in Germany: Solution of an Incest Case Using Bacteriophage M13 Hybridization with Hypervariable Minisatellite DNA

More than 25 blood, serum, and enzyme polymorphisms have been introduced into paternity testing in Germany in recent years (Rittner, 1975). If a “no” decision is defined by exclusion, and a “yes” decision requires a probability of 99.73 % or more, more than 90 % of court cases can be solved in this respect. A few cases not being clarified by a standard expertise include: 1) Cases with more than one alleged man if the men and/or the mother and the men are related. 2) Some cases where the putative father is deceased, and neither the parents nor the legitimate offspring are available for the study. 3) Cases where possible exclusion in a given polymorphic system interferes with an overall evidence in favor of paternity of the alleged man. The “exclusion” could then be traced back to a mutation.

Sex Determination by Genomic Dot Blot Hybridization and HLA DQα Typing by PCR from Fixed Tissues

Recent advances in molecular biology methods have significantly increased the ability to detect genetic variation at the genomic level for forensic purposes. However, the quality requirements for blood, fresh or frozen tissue as a source of DNA are a practical limitation for typing the victim in order to conduct investigations on unsolved cases. Since paraffin embedded specimens are easily obtainable the ability to study this material would be of great value in current forensic practice.

Zur Röntgenidentifizierung unbekannter Leichen bei fortgeschrittenen postmortalen Veränderungen

SummaryThe postmortem changes in the bodies of two individuals were so advanced that the usual identification methods could not be applied; one had drowned and the other died by burning. Antemortem roentgenograms — up to 10 years old — and postmortem X-ray plates were compared and the bodies thus identified. This was possible because the skeleton shows individual, highly specific markers that do not change during life or after death.ZusammenfassungDie postmortalen Veränderungen an einer Wasserleiche und an einer Brandleiche waren so weit fortgeschritten, daß die üblichen Identifizierungsmethoden versagen mußten. Vergleichende röntgenologische Untersuchungen ermöglichten jedoch den sicheren Nachweis der Identität. Der Erfolg beruhte auf der individuellen Variabilität des Skelettsystems und seiner hohen Widerstandsfähigkeit gegenüber intravitalen und postmortalen Einflüssen. Neben der hohen Aussagekraft sind einfache, schnelle Handhabung sowie Dokumentation — ohne Beeinträchtigung der Obduktion — weitere Vorteile der Röntgenidentifizierung. Die vorgestellten Fälle zeigen zudem, daß auch zehn Jahre alte intravitale Vergleichsbilder zur Identifizierung beitragen können.The postmortem changes in the bodies of two individuals were so advanced that the usual identification methods could not be applied; one had drowned and the other died by burning. Antemortem roentgenograms--up to 10 years old--and postmortem X-ray plates were compared and the bodies thus identified. This was possible because the skeleton shows individual, highly specific markers that do not change during life or after death.

HLA DQα Typing of Human Fingernails

In contrast to the extensive knowledge about protein biochemistry of keratinization, little is known about the fate of nuleic acids during these processes (1). It has been suggested that both DNA and RNA completely degenerate in the initial phase of keratinization. However, from electron microscopical studies it is known that nuclear remnants are present (1,3). From these findings and own observations one might expect that nucleic acids should still be available.