An evaluation of DNA fingerprinting for forensic purposes

Abstract

Many highly polymorphic minisatellite loci can be detected simultaneously in the human genome by hybridisation to probes consisting of tandem repeats of the 'core' sequence. The resulting DNA fingerprints produced by Southern blot hybridisation are comprised of multiple hypervariable DNA fragments, show somatic and germline stability and are completely specific to an individual. DNA of high molecular weight can be isolated from blood and semen stains up to 4 years old. Sperm nuclei can be separated from vaginal debris and the sperm DNA examined in isolation, allowing the positive identification of rapists. Correspondingly, vaginal DNA can be isolated from extracts ofpenile swabs. DNA can also beisolatedfromextractsofbuccal swabs. A blind trial involving 4 3 blood samples, 11 bloodstains and 11 semen stains has been successfully carried out. It is envisaged that genetic fingerprinting will shortly form an important part of casework procedure in forensic science laboratories. Materials and methodsDNA fingerprints were produced as described by Jeffreys et al. [ I , 21. DNA was extracted from whole blood, semen, blood stains, semen stains, hair roots, buccal swabs, and semen-free vaginal swabs by overnight incubation in a sodium dodecyl sulphate (SDS) proteinase K/dithiothreitol (DTT) mixture. Approximately 10 pg of vaginal DNA can be obtained from semen-free vaginal swabs. This quantity of DNA will obscure the presence of sperm DNA from semen-contaminated vaginal swabs; hence it is essential to separate sperm from vaginal cells as previously described [31. Vaginal cells from semen-contaminated swabs were preferentially lysed bv a Dreliminarv incubation in the absence of DTT for 30 Abbreviations: SDS, sodium dodecyl sulphate; Dm, dithiothreitol; kb, kilobase min using the lysG misture. Sperm nuclei were pelleted by centrifugation, washed once with the same mixture, repelleted 0 VCH Verlagsgesellschaft mbH, D-

Hypervariable polymorphic VNTR loci for parentage testing and individual identification

“…From the three analyses, the probability that two randomly selected individuals will have the same genotypes was 2.16 x 10 -'5. On the other hand, the probability that randomly chosen two siblings will have the same genotypes was 4.38 x 10-L DISCUSSION DNA probes are now starting to be used widely due to its hypervariable polymorphisms, especially in forensic individualization (Gill et al, 1985(Gill et al, , 1987Jeffreys et al, 1985b), and in paternity suits Jeffreys et al, 1986). Almost all of them are multi-locus probes which recognize several VNTR loci under the conditions of reduced stringency.…”

A Study of Angiotensin Converting Enzyme (ACE) Gene Polymorphism in Essential Hypertension among a Business Community in Punjab

“…The specimens were transported from the place of collection to the laboratory on dry ice and were then stored at -20 0 C till further analysis. DNA was isolated from whole blood using standard protocol of Gill et al (1987). To determine the ACE genotype, genomic DNA samples were amplified by a polymerase chain reaction (PCR) using primer pair such as 5'-CTG GAG AGC CAC TCC CAT CCT TTC T-3' …”

Study of DYS 390 Polymorphism among Khatri Population of Punjab in Comparison to Other Indian and World Population

“…DNA was extracted from blood samples by organic method (Gill et al 1987) After PCR amplification, the samples were electrophoresed on non-denaturing 10% polyacrylamide gel (Maniatis et al 1989) for 18 hr at constant voltage of 100 V. The gels were then silver stained to visualize various alleles at this locus and photographed.…”