Paul Brauner

The use of adhesive tape for recovery of DNA from crime scene items.

Abstract:  The selection of the appropriate method of collection of biological material from crime scene items can be crucial to obtaining a DNA profile. The three techniques commonly used for sampling items are: cutting, swabbing, and taping. The tape sampling technique offers an advantage, in that it enables the collection of a potentially highly informative source of DNA, shed epithelial cells, from selected areas on crime scene items (the inside fingers of a glove, for instance). Furthermore, surface collection of biological material by taping reduces co‐sampling of known PCR inhibitors such as clothing dyes. The correct choice of tape for crime scene item sampling is important. Not all tapes are suitable for biological trace evidence collection as well as DNA extraction. We report on one tape that met both these criteria. Three different cases are presented which demonstrate the usefulness of adhesive tape sampling of crime items. Finally, the advantages of the tape collection technique are discussed and guidelines for preferred areas of tape sampling on various casework items are presented.

Erroneous Gender Identification by the Amelogenin Sex Test

Human gender identification, based on the amelogenin gene, has important applications in forensic casework, prenatal diagnosis, DNA databasing, and blood sample storage. However, we report on the first known case, in the Israeli population, of an amelogenin sex test failure on a phenotypically normal male. He was typed as a female by both the AmpFlSTR SGM plus and GenePrint kits. Subsequent, karyotyping of the soldiers blood sample showed no abnormalities. These results suggest that the determination of sex, based on the amelogenin test, should be interpreted cautiously.

DNA Profiling of Trace Evidence—Mitigating Evidence in a Dog Biting Case

A young girl was the victim of a severe dog attack. An animal, suspected of having caused the attack, was later impounded for investigation. Microclots of blood, recovered from the dogs fur, were analyzed by STR DNA. Results showed that this blood was not related to the biting. Other forensic evidence--hairs, fibers, and odontology--failed to connect a particular animal to the attack. The implications of these findings for the dog and its owners are discussed as well as other forensic methods for resolving such cases.

A condom--the critical link in a rape

An intact condom, reputedly used during a rape, was submitted for forensic examination. Conventional biochemistry results indicated that blood found on one side of the condom may have originated from the victim. Semen from the other side of the condom was not characterizable by conventional biochemical methods. Pubic hairs recovered from the condom matched those of the victim and not those of the suspect. Testing the blood and semen from the condom by DNA analysis gave the profile of the victim from the blood and the profile of the suspect from the semen.

DNA TYPING AND BLOOD TRANSFUSION

As the result of a traffic accident, a man was seriously injured. Investigators found him outside the vehicle he had presumably driven. He was taken to the hospital in an unconscious state and there received a number of blood transfusions. Bloodstains found inside the car were collected and sent for comparison with a posttransfusion blood sample of the victim (suspect). As the car involved in the accident had been stolen, the police wished to ascertain whether there was a link between the suspect and the car. Furthermore, being unconscious, the suspect was unable to give a statement. The bloodstains from the car and the blood of the victim were tested by conventional blood group assays and DNA (RFLP and PCR). By conventional blood group assays, the effect of the blood transfusion were seen. On the other hand, the effect of the transfusion were not at all evident in the DNA assays. The implications of these results are discussed. Transfused blood, even in large quantities, did not alter the DNA profile of the recipient in this case.

Chorionic villus sampling prior to pregnancy termination, a tool for forensic paternity testing

Chorionic villus sampling (CVS), prior to pregnancy termination (pre-termination CVS), is suggested as a tool for forensic paternity testing. Unlike the abortion material, which consists of ruptured tissues of fetal and maternal origin, extra-embryonic membranes obtained through CVS can provide an uncontaminated source of fetal tissue for genotyping. We discuss the possibility of confined placental mosaicism (CPM) and its implications on the polymerase chain reaction (PCR) based analyses of short tandem repeats (STRs) and the D1S80 loci.

The use of acid phosphatase test papers for DNA profiling

The acid phosphatase (AP) test is a routine assay used to screen casework items for the possible presence of semen. This colour test is carried out on filter paper which is retained after testing. Two-year-old AP test papers were found to contain sufficient DNA for short tandem repeat (STR) profiling. Prior to polymerase chain reaction (PCR) amplification, the DNA was preferentially separated into sperm depleted and sperm enriched cell fractions. The implication of these findings for past and present cases is discussed.

STR typing of formalin-fixed paraffin embedded (FFPE) aborted foetal tissue in criminal paternity cases

Sexual assault or rape cases occasionally result in unwanted pregnancies. In almost all such cases the foetus is aborted. A forensic laboratory may receive the foetus, the placenta, or paraffin embedded abortion material for paternity testing. Obtaining a foetal profile DNA from a foetus or placenta may not be successful due to the age or condition of the tissue. Moreover, maternal contamination of placental material will invariably result in a mixed DNA profile. However, the use of properly screened abortion material from paraffin blocks will almost always result in obtaining a foetal DNA profile. Furthermore, foetal tissue fixed in paraffin blocks does not require special conditions for submission and storage as required to preserve fresh foetal or placental tissue. As hospitals routinely prepare foetal tissue in paraffin blocks, which should be readily obtainable by forensic laboratories, these samples would appear to be the preferred choice for paternity testing.

THE EFFECTS OF BLOOD TRANSFUSIONS ON PCR DNA TYPING AT THE CSF1P0, TP0X, TH01, D1S80, HLA-DQA1, LDLR, GYPA, HBGG, D7S8 AND GC LOCI

Pre-transfusion and post-transfusion blood samples from eight individuals were typed at 10 PCR amplified loci. In no case did the PCR DNA profile of the post-transfusion blood sample differ from that of the pre-transfusion profile.

Wall Hangings, Hairs and The Holocaust

Two wall hangings, from the time of the Second World War, were reportedly made from human hair. Laboratory examination of the hangings confirmed this fact. Fibers, holding the wall hangings together, and the weave of the hangings were also examined. Results and implications of the findings are discussed.