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.     

A search for obligatory paternal alleles in a DNA database to find an alleged rapist in a fatherless paternity case

Abstract: A sexual assault case resulted in a pregnancy, which was subsequently aborted. The alleged father of the fetus was unknown. Maternal and fetal types were obtained using the 11‐locus AmpF?STR^® SGM Plus^® kit. The national DNA database was searched for the paternal obligatory alleles and detected two suspects who could not be excluded as father of the male fetus. Additional typing using the AmpF?STR^® Minifiler^? kit, containing three additional autosomal loci, was not sufficient to exclude either suspect. Subsequent typing using the PowerPlex^® 16, containing four additional loci, and Y‐Filer^? kits resulted in excluding one suspect. Searching a database for paternal obligatory alleles can be fruitful, but is fraught with possible false positive results so that finding a match must be taken as only preliminary evidence.     

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.     

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.     

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 dog's 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.