Resolving relationship tests that show ambiguous STR results using autosomal SNPs as supplementary markers

When using a standard battery of STRs for relationship testing a small proportion of analyses can give ambiguous results – where the claimed relationship cannot be confirmed by a high enough paternity index or excluded with fully incompatible genotypes. The majority of such cases arise from unknowingly testing a brother of the true father and observing only a small number of exclusions that can each be interpreted as one- or two-step mutations. Although adding extra STRs might resolve a proportion of cases, there are few properly validated extra STRs available, while the commonly added hypervariable SE33 locus is four times more mutable than average, increasing the risk of ambiguous results. We have found SNPs in large multiplexes are much more informative for both low initial probabilities or ambiguous exclusions and at the same time provide a more reliable genotyping approach for the highly degraded DNA encountered in many identification cases. Eight relationship cases are outlined where the addition of SNP data resolved analyses that had remained ambiguous even with extended STR typing. In addition we have made simulations to ascertain the frequency of failing to obtain exclusions or conclusive probabilities of paternity with different marker sets when a brother of the true father is tested. Results indicate that SNPs are statistically more efficient than STRs in resolving cases that distinguish first-degree relatives in deficient pedigrees.     

SNP分型方法及在法医学等领域的应用

随着单倍型图的产生,SNP越来越受到关注。不仅仅在Y染色体和线粒体,常染色体和X染色体上的SNPs的应用潜能也将被发现。SNPs具有比较低的突变率和适合于降解DNA分析的特点,在法医学领域也受到关注。本文综合介绍了SNPs和X-SNPs的一般特性、分型方法及其在法医学的应用。     

Development of Forensic Assay Signatures for Ebolaviruses

Ebolaviruses are a diverse group of RNA viruses comprising five different species, four of which cause fatal hemorrhagic fever in humans. Because of their high infectivity and lethality, ebolaviruses are considered major biothreat agents. Although detection assays exist, no forensic assays are currently available. Here, we report the development of forensic assays that differentiate ebolaviruses. We performed phylogenetic analyses and identified canonical SNPs for all species, major clades and isolates. TaqMan‐MGB allelic discrimination assays based on these SNPs were designed, screened against synthetic RNA templates, and validated against ebolavirus genomic RNAs. A total of 45 assays were validated to provide 100% coverage of the species and variants with additional resolution at the isolate level. These assays enabled accurate forensic analysis on 4 “unknown” ebolaviruses. Unknowns were correctly classified to species and variant. A goal of providing resolution below the isolate level was not successful. These high‐resolution forensic assays allow rapid and accurate genotyping of ebolaviruses for forensic investigations.     

A Dominant SNP in a Unionist Scotland? The 2019 UK General Election in Scotland

The UK general election in December 2019 produced a resounding victory for Boris Johnson’s Conservatives, returning a majority government and the mandate for Brexit that he had campaigned for. The picture was less rosy for the Conservatives in Scotland, where his party lost half its seats to the SNP. This article reviews the election outcome in Scotland, considering the fortunes of each of the main parties, and projects forward to the devolved election in 2021, when the parties will once again debate the key constitutional question in Scotland.     

Population data for 94 identity SNPs in four U.S. population groups

The U.S. National Institute of Standards and Technology (NIST) sequenced 1036 human DNA samples from four United States population groups (African American, Asian, Hispanic, and Caucasian) using the ForenSeq DNA Signature Prep Kit with Primer Mix B (DPMB) on a MiSeq FGx instrument. In addition to STR markers, DPMB includes amplification primers for single nucleotide polymorphisms (SNPs) used for individual identification (iiSNPs, n = 94), ancestry inference (aiSNPs, n = 56), and phenotype prediction (piSNPs, n = 22). Resulting sequencing coverage information was interpreted for the 94 iiSNP markers. Here we present performance characteristics of the ForenSeq DNA Signature Prep Kit in the population studied.     

Make it "SNPPY" - Updates to SRM 2391d: PCR-Based DNA Profiling Standard

Standard Reference Material (SRM) 2391d: PCR-Based DNA Profiling Standard was released to the forensic community in 2019. Next Generation Sequencing (NGS) was used as the primary method of certification, where certified values were assigned when a high coverage sequence string was available for a marker. Using NGS to assign values has allowed for additional marker sets beyond short tandem repeat (STR) loci, including single nucleotide polymorphisms (SNPs) and mitochondrial DNA (mtDNA) whole genome sequences, to be included in the Certificate of Analysis (COA). Since the 2019 release, several commercial NGS panels have become available including the Verogen ForenSeq mtDNA Control Region, mtDNA Whole Genome, MainstAY, and Kintelligence Kits. In addition, three community Ion AmpliSeq panels from Thermo Fisher (MH-74 Plex, VISAGE, and Y-SNP) are now available. While the mtDNA whole genome sequence for the components are already included and no new STR markers are introduced by MainstAY, the other recently released panels allow for the inclusion of > 11,000 additional SNPs (e.g., identity, ancestry, phenotype, kinship, and X- and Y-SNPs) and 74 microhaplotypes to the COA for SRM 2391d in an update completed by fall of 2022.     

Analysis of genetic polymorphisms associated with the presence of freckles for phenotypic prediction

The prediction of externally visible characteristics (EVCs) is a commonly used practice by the forensic sciences as an important resource in the investigation of criminal cases in which the identity of perpetrators or victims is unknown or even to recognize decomposed cadavers. With this purpose, genetic markers associated with pigmentation traits have been widely studied by forensic scientists and, nowadays, it is possible to predict phenotypic characteristics such as hair, eyes and skin colour, as well as the presence of skin freckles by analysing single nucleotide polymorphisms (SNPs). In this study, we analysed the association of six SNPs located in pigmentation genes to the presence of freckles in individuals from the Brazilian population for forensic DNA phenotyping. The study was based within the context of a larger project on a population sample of 534 adult Brazilians of both sexes and different skin colours. DNA was extracted from peripheral blood and genotyped using the TaqMan® OpenArray® Real-Time PCR System (ThermoFischer Scientific) technique. Statistical analyses were carried out with the R software (version 4.0.2). As for the results obtained, three SNPs were shown to be statistically associated to the freckling, rs12203592, rs1800404 and rs222847, with CT, AG and AA genotypes being the main contributors, respectively. Variables such as sex of the individuals and skin colour were found to also contribute to the manifestation of this pigmentation trait. Further statistical analyses will be carried out to evaluate the possibility of using the SNPs in this study for phenotyping prediction of the Brazilian population, improving existing DNA phenotyping models in forensic sciences.     

Westminster No More? Governance,Devolution and Delegation in Scotland

Abstract

Politicians have returned frequently to the need to reform schools to achieve wider objectives of social reform and economic prosperity. Within the UK education systems, however, there have been differing experiences and approaches at both national (Scottish, English, Welsh and Northern Irish) and local levels towards school governance reform. School governance in Scotland remains distinct compared to the rest of the UK, both in terms of the pace of reform and the content. The pace of reform in Scotland has been slower and the content has been shaped to a greater extent by political and professional modes of accountability. This article argues that a new phase in school governance reform is likely to follow the election of the Scottish National Party (SNP) majority government in May 2011. A number of factors both external (international comparison of the school performance; the post 2008 politics of austerity) and internal (changes led by the SNP government to the policy-making process, namely outcomes-based policy-making) have placed debates about school autonomy and school governance on the political agenda.