Abstract: Analysis for short tandem repeat (STR) loci is widely performed in forensic laboratories for human identification that utilizes commercially available kits that employ fluorescently labeled primers and capillary electrophoresis. With only a few exceptions, the sequences of the primers included in a kit are not disclosed by the kit manufacturers. Therefore, we developed a simple method to determine the 5? end of the binding site of the primers included in commercial kits. Our method requires only custom primers and human genome sequence data and routinely used equipment and consumables. One or two custom primers are added to the PCR reaction mixture containing kit primers and input human DNA prior to amplification, and PCR products are separated by capillary electrophoresis after amplification. With this method we can determine which primer of the pair is fluorescently labeled and the 5? end of the binding site of primers based on the changes in an electropherogram that are caused by the addition of the custom primer(s), and the human genome sequence data. This method also is useful for the determination of the shortest possible lengths of labeled kit primers.
The city of Melbourne welcomed the participants of the 25th international ISFG with crisp, sunny spring weather, friendly people and a spectacular meeting venue. The Melbourne Convention and Exhibition Centre was a very modern and generous space, which easily accommodated the large poster and vendor exhibition and provided many opportunities to meet and talk to colleagues.
Abstract: The previously published genetic identification of presumptive samples attributed to two French kings, Henri IV and Louis XVI, by Charlier et al., was recently refuted by a genetic genealogic approach. This (provisional) refutation illustrates the difficulties in confirming the identification of historical DNA samples using limited genetic data. Therefore, we want to stress the necessity of including the genetic genealogic approach – which relies on DNA typing of living relatives of the presumptive donor as a confirmed reference – to validate genetic results in historical cases. Moreover, the popularity and broad media coverage of such studies are useful in bringing awareness to the general public, non-DNA forensic experts and lawyers about the complexity of DNA typing in forensic cases.
Abstract: The standardization of methods for individualizing Cannabis sativa plants could offer new possibilities in the investigation of its illegal trade. Here we present the first nomenclature proposal for 15 cannabis STRs, which allows an initial standardization for performing comparisons between laboratories and generating genotype databases. Several alleles of the 15 STR loci have been sequenced. This has revealed that not all the STR loci are equally suitable for the individualization purposes. Moreover, several nucleotide variations have been detected both inside the repeat structure and/or in the flanking region. All the different SNPSTR haplotypes are presented and compared with the previous sequence raw data of the 15 STR loci. The SNPSTR data could considerably increase the informative value of the STRs, which could be very useful in complex cases.
New research from Queen Mary University of London shows released prisoners with schizophrenia are three times more likely to be violent than other prisoners, but only if they receive no treatment or follow-up support from mental health services.
The Associated Press reports the president needs breakthroughs on three fronts: the cancellations and technology messes and the crisis in confidence among his own supporters. Meanwhile, The Wall Street Journal reports the White House is probing how the rollout flopped despite what they had believed was sufficient planning.
Abstract: The Y haplotype population-genetic terrain is better explored from a fresh perspective rather than by analogy with the more familiar autosomal ideas. For haplotype matching probabilities, versus for autosomal matching probabilities, explicit attention to modeling – such as how evolution got us where we are – is much more important while consideration of population frequency is much less so. This paper explores, extends, and explains some of the concepts of “Fundamental problem of forensic mathematics – the evidential strength of a rare haplotype match” . That earlier paper presented and validated a “kappa method” formula for the evidential strength when a suspect matches a previously unseen haplotype (such as a Y-haplotype) at the crime scene. Mathematical implications of the kappa method are intuitive and reasonable. Suspicions to the contrary raised in rest on elementary errors.Critical to deriving the kappa method or any sensible evidential calculation is understanding that thinking about haplotype population frequency is a red herring; the pivotal question is one of matching probability. But confusion between the two is unfortunately institutionalized in much of the forensic world. Examples make clear why (matching) probability is not (population) frequency and why uncertainty intervals on matching probabilities are merely confused thinking. Forensic matching calculations should be based on a model, on stipulated premises. The model inevitably only approximates reality, and any error in the results comes only from error in the model, the inexactness of the approximation. Sampling variation does not measure that inexactness and hence is not helpful in explaining evidence and is in fact an impediment.Alternative haplotype matching probability approaches that various authors have considered are reviewed. Some are based on no model and cannot be taken seriously. For the others, some evaluation of the models is discussed. Recent evidence supports the adequacy of the simple exchangability model on which the kappa method rests. However, to make progress toward forensic calculation of Y haplotype mixture evidence a different tack is needed. The “Laplace distribution” model of Andersen et al which estimates haplotype frequencies by identifying haplotype clusters in population data looks useful.
In a letter published in this same issue, Liu et al. reply to a recently published article by us contesting the main conclusion of our original paper, namely, that gender is a factor that contributes to the explanation of the discrepancies in eye colour prediction based on the HERC2/OCA2 genotype and the IrisPlex model . Their main point of critique to our work seems to be the small sample size used in the study, arguing that our results were strongly influenced by sample size effects and by the low blue eye frequency naturally occurring in the Spanish and other Mediterranean populations.
Epidemiological methods used during the investigation of fatal injuries makes the results more accurate, and allows for greater legal certainty of conclusions. Michael Freeman will address this as he defends his thesis at Umeå University, Sweden, on November 6.
Several microsatellites PCR (polymerase chain reaction) multiplex systems (i.e. for simultaneous typing) have been reported for forensic analysis. These include autosomal STR multiplex kits widely used which are commercially available. These commercial kits are generally based on the Combined DNA Index System (CODIS) loci, and a huge volume of genetic population data for the CODIS loci from different ethnic groups has been reported . Nevertheless, there are hundreds of other highly polymorphic STR loci unlinked to the current CODIS loci (non-CODIS markers), which are also useful for forensic genetics . Analysis of further non-CODIS STR loci may complement information from CODIS loci, offering powerful tools for difficult kinship testing, such as sib-ship testing or testing for deficient paternity cases .