Interrogation of short tandem repeats using fluorescent probes and melting curve analysis: A step towards rapid DNA identity screening

Current forensic DNA profiling methods rely on the analysis of samples at specialised laboratories with an average turnaround time of several days. The ability to rapidly determine a partial profile of short tandem repeats at the point-of-arrest would be of great benefit to police forces around the world, for example enabling a suspect to be rapidly included or excluded from an investigation. We have developed a homogeneous PCR method for the interrogation of STR loci utilising fluorescent oligonucleotide probes and melting curve analysis. Alleles of the D18S51, TH01 and D8S1179 loci were differentiated and identified on the basis of target length and probe melting temperature. Assay performance was evaluated by comparing melting peak data with the AmpFlSTR^® SGM Plus^® system. The method is compatible with direct analysis of unpurified buccal swab samples, enabling a partial STR profile to be generated within 1 h.     

A comparison of insanity defense standards on juror decision making

Following the Hinckley acquittal, 17 states and the federal government made changes to the insanity defense, including revising the standard, reassigning the burden of proof, and altering the standard of proof. Two studies were conducted to determine whether the specific insanity standard (including the assignment of burden of proof and standard of proof) employed had a significant effect on mock jurors' verdicts. Participants' comprehension of insanity defense instructions was measured and the factors jurors used to decide whether to find the defendant not guilty by reason of insanity (NGRI) were also assessed. Participants' comprehension of insanity defense standards was very low. When asked to identify the factors they considered important in determining whether to find a defendant NGRI, only three elements of insanity defense standards were identified as significant. The results may have important implications for policy decisions regarding the insanity defense.     

The use of personal computers for the mathematical processing of the results of chemical-toxicological studies]

Three programs in BASIC and SUPER BASIC language for personal computer are suggested. The first program makes it possible to calculate the degree of substance extraction and factor of its distribution between two liquid immiscible phases. The second program is designed to make calculations on distribution of substance in the organs of experimental animals. The third program is designed to determine specific and molar factors of light absorption. Results of calculations are presented as tables. Programs can be also used in mathematical processing of results obtained in the course of scientific research.     

The analysis and comparison of blue wool fibre populations found at random on clothing.

Fifty-eight garments were taped and searched for mid to dark blue wool fibres. These were then removed from the tapings, mounted on slides and examined using a high-power microscope (400x). A total of 2,740 blue wool fibres were identified and visible range microspectrophotometry (MSP) was performed on them. Three hundred independent blue wool populations were identified on 56 of the 58 garments searched. The lack of control fibres meant the spectral range of each population was unknown. The number of populations may have been underestimated by grouping together the fibres that had broad single peaks and a lack of distinguishing features in the spectra. Although blue wool is considered to be a common fibre type, 300 unique spectral shapes were identified by the use of microspectrophotometry alone. This demonstrates that the dyes used in the dyeing of blue wool are variable. Showing that many different populations of blue wool occur on a range of garments should ensure that the forensic scientist does not underestimate or understate the strength of evidence in cases where blue wool is found. Hopefully this work will enlighten scientists and enable them to also assess the true value of their findings when other commonly occurring fibres are encountered.     

A simple logical approach to questioned envelopes examination.

This case report outlines research undertaken as the result of a document examination case in which two envelopes were involved. The combination of the circumstances of the case and the results of the examination allows a simple application of a logical approach to pre-assess the probability that an envelope (or a package) potentially recovered at a suspect's home comes from the same batch (same source) as questioned envelopes. This highlights that it is useful to examine envelopes.