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D J Werrett

Publications and source records attributed to D J Werrett.

27 records · Page 2Linked to original sources
PubMedDate not supplied

A comparison of the isoelectric focusing patterns of red cell phosphoglucomutase separated on an ampholine, ampholine/separator and immobilised pH gradient.

The isoelectric focusing patterns of red cell phosphoglucomutase (PGM1) separated on Ampholine, Ampholine/separator and rehydratable immobilised pH gradients have been compared. The sharpest and most intense zymograms have been observed on immobilised pH gradients provided that Ampholine was added during the rehydration of the gel. The addition of ampholine in the rehydration of Immobiline plates has been shown to improve the sharpness and intensity of the zymogram obtained and the potential of immobilised pH gradients for PGM typing has been demonstrated.

Ampholyte Mixtures↗
PubMedDate not supplied

Immunological detection of human phosphoglucomutase (PGM 1) subtypes.

Anti-phosphoglucomutase (PGM) antibodies have been produced by immunising a sheep with a purified preparation of rabbit skeletal muscle PGM and used to devise an immunological procedure for detecting PGM isozymes after isoelectric focusing. The anti-rabbit PGM antibodies cross react with human PGM and can be used to identify the PGM1 isozymes characteristic of this polymorphism. The patterns revealed by immunodetection are exactly comparable with those obtained by isozyme staining.

Animals↗
PubMedDate not supplied

Report of a European collaborative exercise comparing DNA typing results using a single locus VNTR probe.

A collaborative exercise was carried out in 1989 among 12 European forensic laboratories using the single locus VNTR probe pYNH24, the restriction enzyme HinfI, the same set of human genomic DNA samples, and a standardized DNA size marker. The objectives of the exercise were: (1) to study the degree of variation within and between laboratories, (2) to obtain information on requirements for technical standardization allowing the exchange of typing results and (3) to compare different approaches for the identification of allelic DNA fragments of unknown size. Each laboratory carried out up to 10 independent typing experiments using the same DNA samples. The results were analysed independently by two laboratories using three different methods. The results of the exercise demonstrate the correlation of typing that can be achieved within and between laboratories under conditions of minimal standardization.

Alleles↗
PubMedDate not supplied

The collaborative study on typing group-specific component by eight forensic science laboratories.

This report describes a collaborative study on typing group-specific component (GC), conducted between the Central Research and Support Establishment and the forensic science laboratories of England, Wales and Northern Ireland. A population study (n=114) was performed. Fifty blood donors were selected to provide a distribution, slightly biased from normal, in favour of the GC 1F-1F and GC 1F-1S phenotypes. A protocol was devised for preparing large bloodstains. The strongest GC bands were obtained from the edge of a stain after the blood had been treated with K+/EDTA. Each laboratory received a representative portion of the large bloodstains for GC typing. Five of the eight laboratories correctly grouped all the bloodstains. No errors directly attitributable to the system were recorded in over 800 tests, indicating that GC in bloodstains can be typed reliably using the combination of isoelectric focusing in ultrathin narrow pH interval gels followed by immunofixation and silver staining.

Blood Donors↗
PubMedDate not supplied

Paternity calculations from DNA multilocus profiles.

DNA profiles prepared using multilocus probes can provide valuable evidence in cases of disputed parentage. This paper describes a simple approach to the analysis of the profiles from a mother, child and putative father in a case of disputed paternity. Although the treatment has not yet been extended to deal with cases in which mutant bands may have appeared, it has already proved useful in casework. The analysis is illustrated by a numerical example calculated on a computer spreadsheet.

Bayes Theorem↗
PubMedDate not supplied

The collaborative study on typing group-specific component in casework bloodstains.

Casework bloodstains were typed for group-specific component (GC) at eight forensic laboratories. Approximately 600 bloodstains were examined of which a mean of 62.7% gave results. This is comparable to other blood grouping systems in current use. Stains that were over three-months old were successfully typed in six of the laboratories. A wide variety of substrates was examined; these included many items of clothing as well as metal blades, concrete, paint, cement, glass and grass. Of substrates that were examined several times, none consistently gave problems with GC typing. The GC system has been shown, therefore, to be an effective test in operational forensic science.

Blood Grouping and Crossmatching↗
PubMedDate not supplied

Evaluation and presentation of forensic DNA evidence in European laboratories.

The first part of this article describes Bayes' theorem and its practical application to scientific evidence. Secondly, statements proposed by European DNA laboratories are presented, analysed and commented upon. Finally, the authors reiterate their proposal of adopting a likelihood ratio framework justified by the usefulness of the approach in practical context of DNA cases. Note that this framework underlines the main questions the experts have to answer at trial: to what degree does the evidence support the prosecutor's hypothesis? and to what degree does the evidence support the defence's hypothesis?

Bayes Theorem↗
PubMedDate not supplied

Forensic application of DNA 'fingerprints'.

Many highly polymorphic minisatellite loci can be detected simultaneously in the human genome by hybridization to probes consisting of tandem repeats of the 'core' sequence. The resulting DNA fingerprints produced by Southern blot hybridization are comprised of multiple hypervariable DNA fragments, show somatic and germline stability and are completely specific to an individual. We now show that this technique can be used for forensic purposes; DNA of high relative molecular mass (Mr) can be isolated from 4-yr-old bloodstains and semen stains made on cotton cloth and digested to produce DNA fingerprints suitable for individual identification. Further, sperm nuclei can be separated from vaginal cellular debris, obtained from semen-contaminated vaginal swabs, enabling positive identification of the male donor/suspect. It is envisaged that DNA fingerprinting will revolutionize forensic biology particularly with regard to the identification of rape suspects.

Blood Proteins↗