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Comparisons of DNA profiles recovered from the crime-scene and a person through short tandem repeat (STR) analysis using capillary electrophoresis (CE) is the gold standard method of determining a match. A comparison of STR profiles generated using CE to massively parallel sequencing (MPS) methods was undertaken. The results showed CE methods recovered high percentages of autosomal or Y-STR markers individually, however, MPS produced more information at low inputs and a higher number of STR markers overall, showing the potential of MPS to provide additional data to assist in solving major crimes. [ABSTRACT FROM AUTHOR]

We report on a comparison of the performance of the Applied Biosystems® SeqStudioTM Genetic Analyzer with the 3500 Genetic Analyzer when analysing trace DNA samples. Totally, 162 profiles generated from 'trace DNA' were analysed on both instruments with comparable number of alleles detected, relative fluorescence units (RFU) and likelihood ratio (LR) values. The SeqStudioTM was found to be suitable for the analysis of trace DNA samples. [ABSTRACT FROM AUTHOR]

Generating degraded DNA samples can be useful for forensic DNA research as this can mimic the condition of crime scene samples and results from such samples. Methods which use quick and cost-effective ultraviolet light (UV) exposure can be utilized to degrade DNA but are not well documented. This study aimed to establish a procedure and define the parameters required to generate Short Tandem Repeat (STR) profiles at different degradation levels. UV exposure times between 0 and 60 s were tested using genomic and control DNA. Sample eluates were quantified with QuantifilerTM Trio pre- and post-UV exposure, and select samples were profiled using PowerPlex® 21. Quantification data and STR profiles were analysed to identify metrics which indicated degradation severity. Samples were observed to be degraded by UV exposure as evidenced by established DNA degradation markers. No specific metric was identified to reliably determine the severity of sample degradation, but it was noted that UV exposure between 5 and 10 s resulted in mild degradation, between 15 and 25 s generated moderate degradation, and between 45 and 60 s resulted in severe degradation in STR profiles. This study indicates that quantification before and after UV exposure may be useful to estimate the degree of degradation via one quantification target. [ABSTRACT FROM AUTHOR]

Previous studies examining whether splitting the DNA extract for replicate amplification versus maximizing the template available for a 'one-shot' amplification either examined the benefits of using replicates (without a comparison to a single amplification), or used semi-continuous probabilistic software that ignores peak height information. In this study, we use a fully continuous probabilistic genotyping software to compare the effectiveness of amplifying a single sample compared to splitting the sample and conducting a joint analysis of replicate amplifications. We show that the one-shot approach is marginally better than splitting the DNA extract across a range of contributor numbers and template amounts. Where there is unexpected peak height variability or drop-in within the profile not modelled during interpretation, a replicate approach may be better. [ABSTRACT FROM AUTHOR]

The present study was designed to explore the STR diversity and genomic history of the inhabitants of Nayagarh district of Odisha, India. We also tested the proficiency of the most recent, new generation PowerPlexR Y23 multiplex system for forensic characterisation and to decipher the phylogenetic affinities. The genetic diversity and polymorphism among 236 healthy unrelated male volunteers from Nayagarh district of Odisha, India was investigated. This investigation was carried out via 23 Y-chromosomal STRs using capillary electrophoresis. A total 223 unique haplotypes were reported. Discrimination capacity (DC), gene diversity (GD) and power of discrimination (PD) were observed as 0.945, 0.999999999998333, and 0.99999999999794, respectively. Polymorphic information content (PIC) and matching probability (PM) were reported as 0.999999999925535 and 2.06 × 10−12, respectively. Simultaneously, the haplogroup analysis characterised with C2, E1b1a, E1b1b, G2a, H1, I2a, J2a, J2b, L, O, O1, O2, Q, R1a, R2, and T haplogroups, disclosing the possible geographical relatedness of the studied population to different areas of the world. Phylogenetic analysis with previously reported Indian and Asian populations showed the genetic closeness of the studied population to different Indian populations and the Bangladeshi population of Dhaka, whereas the Bhotra population of Odisha and Han population of China showed much less genetic affinity. [ABSTRACT FROM AUTHOR]

Ramos and Gonzalez-Rodriguez introduce the concept of calibration in order to determine whether a system of evidence presentation is a reliable assessor of evidential weight. In this paper, we apply this calibration method to a dataset of mixed forensic DNA profiles generated using the QIAGEN Investigator® 24plex QS Kit and interpreted using the probabilistic genotyping software STRmix™.We describe the methodology for applying calibration to sets of forensic DNA profiles. We observe an approximate correspondence of the posterior probability, as assigned from the LR and the prior odds, with the observed rate of true donors for this dataset. [ABSTRACT FROM AUTHOR]

The advent of DNA profiling in the 1980s has revolutionised forensic science. Forensic DNA profiling is a powerful tool that is used to both exonerate and implicate persons of interest in criminal cases. The technologies used to recover and detect DNA from crime scene stains have evolved over time. Whereas 30 years ago most forensic profiles were generated from visible stains such as blood or semen, nowadays, DNA profiles are often generated from trace amounts of DNA including touched items. The DNA in these profiles is often compromised in quantity and quality, and frequently originates from more than one individual. This improved sensitivity has complicated the interpretation of forensic DNA profiles, and consequently improved methods of profile interpretation have had to be developed. The adoption of these methods has meant that forensic scientists can now interpret mixed DNA profiles previously thought to be too complicated. This article reviews the history of forensic DNA profiling globally, introduces the challenges of DNA profile interpretation, discusses why the community is adopting improved methods, and reflects on what new technology is on the horizon and the new challenges that may present. [ABSTRACT FROM AUTHOR]

The ABO blood group is considered to be one of the most important markers in forensic testing. Additionally, autosomal short tandem repeat (STR) genotyping continues to be recognized as the dominant technique for determination of human identity, and Y chromosome STR (Y-STR) analysis is becoming increasingly important in solving criminal cases. In this paper, we describe an integrated amplification system of ABO, autosomal STR, and Y-STR genotyping in a single reaction. This system allows for the simultaneous detection of 18 autosomal STR loci (13 Combined DNA Index System [CODIS] loci, as well as D2S1338, D6S1043, D12S391, Penta D, and Penta E), the ABO blood group locus, the Y-STR locus DYS391, and the sex-determining amelogenin locus. Primers were designed and optimized for amplicon sizes from 80–420 bp using a five-dye fluorescent design with the fifth dye reserved for the internal size standard. Sensitivity assays resulted in successful amplification of genomic DNA in the range of 0.250–2.000 ng. A total of 90 individuals from the Chinese Han population were studied using the system and forensic genetic data are presented. We conclude that this integrated system could be an updated and improved solution for forensic DNA analysis. [ABSTRACT FROM AUTHOR]

Law enforcement is moving from targeted forensic DNA analysis to more extensive use of genomics in support of criminal investigations and for related purposes, such as the identification of human remains. The field of forensic genomics is data-driven and will continue to evolve as new capabilities are developed and new datasets are made accessible. Intelligence capabilities using forensic genomics include the prediction of externally visible characteristics and biogeographical ancestry, and the relatively new field of forensic genetic genealogy. This technique expands these capabilities by accessing public genetic datasets to identify potential relatives of the donor of DNA relating to an investigation. This exploitation of public datasets poses a range of ethical, legal and privacy challenges. The extended reach of these techniques expands these issues to entire families, across multiple jurisdictions. These legal challenges increase as attention turns to much larger, but less accessible, genetic data held by direct-to-consumer genetic genealogy providers. [ABSTRACT FROM AUTHOR]

Firearm-related exhibits are often found at crime scenes. These exhibits may include the firearm, cartridges, cartridges cases or bullets. As ammunition needs to be handled to load the weapon, regardless of the action or loading type, DNA may be deposited onto the ammunition via touch. As reproducible DNA profiles have been obtained from fired cartridge casings and Improvised Explosive Device (IED) fragments, it is possible that quantifiable amounts of DNA could be recovered from fired bullets. A series of 40 Winchester PowerPoint 22LR 42 grain HP Copper Plated bullets were loaded with serially diluted cell suspensions obtained from a female donor. These were shot into 500 sheet reams of A3 paper for capture and returned to a sterile DNA laboratory for removal, extraction and quantification of DNA. Repeatable partial profiles with five reportable loci pairs consistent with the cell donor were obtained in one replicate of the neat sample. Weak partial profiles were also present in 1:2, 1:5 and 1:10 dilutions. To our knowledge, this is the first reported evidence of DNA surviving the cycle of fire and being recovered from a fired bullet under controlled conditions. [ABSTRACT FROM AUTHOR]

Bloodstains are extremely important forensic evidence for DNA profiling. The current study has been planned to quantify DNA recovery from a list of fabrics tested after washing. On each fabric, spots of blood was dotted, and the dried-bloodstained fabrics were hand washed with tap water, soaked in tap water with detergent and then hand washed, for 5 and 10 min. DNA was extracted through Chelex100 from these fabrics and quantified through Real Time PCR using the Quantifiler Human DNA Quantification kit. Results showed that DNA can be recovered from fabrics after they have been washed. The amount of recovered DNA is comparable among these fabrics and did not show significant variations with washing methods. Blends of fabrics showed the highest recovery while non-absorbent fabrics showed least DNA recovery. Knowledge of the different DNA quantities recovered from washed fabrics will be useful in solving criminal cases. The ability to recover DNA from washed fabrics could prove important in forensic casework. [ABSTRACT FROM AUTHOR]

A new phenomenon was detected using the Applied Biosystems 3500xL Genetic Analyzer. This phenomenon is characterised by a strong sample in an injection imparting low-level peaks to negative control samples positioned anywhere within the same injection. The affected negative controls did not display these peaks when processed in the absence of the strong sample. This phenomenon, hereafter described as ‘signal interference’, has been demonstrated to be an extension of the widely accepted capillary electrophoresis anomaly known as ‘crosstalk’. Signal interference has been observed in casework profile analysis and the potential implications for casework are discussed. [ABSTRACT FROM PUBLISHER]

This paper describes the analysis of population data typed using the Promega PowerPlex 21 multiplex for the three major sub populations within Australia. Samples from 1427 declared Australian Aboriginal, 546 Pure Aboriginals from the Northern Territory, 990 Asian, and 1707 Caucasian individuals representing were analysed. Departures from Hardy–Weinberg equilibrium (HWE) and linkage equilibrium (LE) were assessed using exact tests. The Aboriginal populations were shown to display significant departures from equilibrium. All four subpopulation databases are of suitable size for the purpose of estimating allele frequencies. [ABSTRACT FROM PUBLISHER]

Selected profiles typed at the Promega PowerPlex 21 (PP21) loci were examined to determine if a linear or exponential model best described the relationship between peak height and molecular weight. There were fewer large departures from observed and expected peak heights using the exponential model. The larger differences that were observed were exclusively at the high molecular weight loci. We conclude that the data supports the use of an exponential curve to model peak heights versus molecular weight in PP21 profiles. We believe this observation will improve our ability to model expected peak heights for use in DNA interpretation software. [ABSTRACT FROM PUBLISHER]