Providing scientific guidance on DNA to the judiciary.

A series of short documents have been written in response to a request from the UK Judiciary for explanations of research that was commissioned in response to questions they had raised. These related principally to the potential impact of primer binding site mutation (PBSM) but it became clear at an early stage that it was necessary to explain related issues. The three scientific guidance papers (SGPs) that have been prepared thus far are presented in their entirety so that UK scientists may be aware of what has been presented to judges. Suggestions for further work, including possible communication to jurors are discussed.

Is it to the advantage of a defendant to infer a greater number of contributors to a questioned sample than is necessary to explain the observed DNA profile?

When a forensic scientist presents the results of a comparison between a DNA profile from a questioned sample with that of a defendant the interpretation will be based on the premise of a given number of contributors. It is quite common practice for defence counsel to ask how consideration of a greater number of putative contributors to the profile would affect the interpretation. This note discusses the response to such a request.

Considerations on the application of a mutation model for Y-STR interpretation.

If Y-STR profiling is to be more effective in criminal casework, the methods used to evaluate evidential weight require improvement. Many forensic scientists assign an evidential weight by estimating the number of times a Y-STR profile obtained from a questioned sample has been observed in YHRD datasets. More sophisticated models have been suggested but not yet implemented into routine casework, e.g. Andersen & Balding [1]. Mutation is inherent to STR meiosis (or inheritance) and is encountered in practice. We evaluated a mutation model that can be incorporated into a method for assigning evidential weight to Y-STR profiles, an essential part of bringing any method into practice. Since an important part of implementation to casework is communication, the article is written in an accessible format for practitioners as well as statisticians. The mutation component within the MUTEA model by Willems et al. [2] incorporates the potential for multistep mutations and a tendency for alleles to revert towards a central length, reflecting observed mutation data, e.g. [3]. We have estimated the parameters in this model and in a simplified symmetric version of this model, using sequence data from father/son pairs [4] and deep-rooted pedigrees [5]. Both datasets contain multistep mutations, which may have an effect on models based on simulations [1]. We introduce Beta-Binomial and Beta-Geometric conjugate analyses for estimating rate and step parameters for the mutation models presented here, which require only summations and multiplications. We proved mathematically that the parameters can be estimated independently. We show the importance of reporting the variability of the parameters and not only a point estimate. The parameters can be easily incorporated into statistical models, and updated sequentially as more data becomes available. We recommend fuller publication of data to enable the development and evaluation of a wider range of mutation models.

Consideration of the probative value of single donor 15-plex STR profiles in UK populations and its presentation in UK courts.

The adoption of new 15 locus STR multiplex systems into UK forensic science would be facilitated by agreed guidelines for reporting the strength of DNA evidence using likelihood ratios. To facilitate such an agreement, we present an analysis of previously published UK allele frequencies for white Caucasian, Afro-Caribbean and Indo-Pakistani populations and investigate their effect on likelihood ratios for single donor profiles. We consider the implication of the five additional loci and suggest a procedure for reporting likelihood ratios for 15-plex STR profiles.

Interpretation and reporting of mixed DNA profiles by seven forensic laboratories in the UK and Ireland.

In 2014, the UK Forensic Science Regulator (FSR) commissioned a collaborative trial to assess the methods used by forensic service providers (FSPs) in the UK and Ireland for analysis, interpretation and reporting of mixed DNA profiles. Five different mixed samples of varying complexity with supporting mock case circumstances were tested using SGMPlus™ and the newly introduced DNA-17(+) multiplexes and reported by participating laboratories. The results demonstrated a high degree of consistency in analytical methods and allele designations, but some variation in the statistical evaluation and reporting of results. Some of the differences noted were attributable to the major technology change to 17(+)-STR systems which had recently been implemented across the UK at that time. The FSR made recommendations based on the trial outcomes which were intended to produce a more consistent approach to mixtures analysis, interpretation and reporting. Four years later, the Association of Forensic Science Providers (AFSP) repeated the trial, with all major UK and Ireland FSPs (both public sector and private companies) again participating. This second trial used the same mixture set as the 2014 trial but was focussed on the methods for interpretation and evaluation. Since 2014, all UK and Ireland FSPs have implemented probabilistic statistical software using continuous models enabling statistical evaluation of more complex mixtures than was possible in 2014. The trial was therefore aimed at investigating the value of these improved capabilities and also to investigate if there appeared to be marked differences between the different software tools in use in the UK. The results demonstrate a high degree of concordance within and between FSPs and across different evaluation models, and will provide important support for the use of such models in evaluation of mixed DNA profiles.

Interpretation of DNA data within the context of UK forensic science - investigation.

This article is the second part of a review of the interpretation of DNA data in forensic science. The first part describes the evaluation of autosomal profile for criminal trials where an evidential weight is assigned to the profile of a person of interest (POI) and a crime-scene profile. This part describes the state of the art and future advances in the interpretation of forensic DNA data for providing intelligence information during an investigation. Forensic DNA is crucial in the investigative phase of an undetected crime where a POI needs to be identified. A sample taken from a crime scene is profiled using a range of forensic DNA tests. This review covers investigation using autosomal profiles including searching national and international crime and reference DNA databases. Other investigative methodologies described are kinship analysis; familial searching; Y chromosome (Y-STR) and mitochondrial (mtDNA) profiles; appearance prediction and geographic ancestry; forensic genetic genealogy; and body identification. For completeness, the evaluation of Y-STRs, mtDNA and kinship analysis are briefly described. Taken together, parts I and II, cover the range of interpretation of DNA data in a forensic context.

Interpretation of DNA data within the context of UK forensic science - evaluation.

Forensic DNA provides a striking contribution to the provision of justice worldwide. It has proven to be crucial in the investigative phase of an unsolved crime where a suspect needs to be identified, e.g. from a DNA database search both nationally and internationally. It is also a powerful tool in the assignment of evidential weight to the comparison of a profile of a person of interest and a crime scene profile. The focus of this document is the evaluation of autosomal profiles for criminal trials in the UK. A separate review covers investigation and evaluation of Y-STR profiles, investigation using autosomal profiles, kinship analysis, body identification and Forensic Genetic Genealogy investigations. In less than 40 years, forensic DNA profiling has developed from a specialist technique to everyday use. Borrowing on advances in genome typing technology, forensic DNA profiling has experienced a substantial increase in its sensitivity and informativeness. Alongside this development, novel interpretation methodologies have also been introduced. This document describes the state of the art and future advances in the interpretation of forensic DNA data.

A comment on the PCAST report: Skip the "match"/"non-match" stage.

This letter comments on the report "Forensic science in criminal courts: Ensuring scientific validity of feature-comparison methods" recently released by the President's Council of Advisors on Science and Technology (PCAST). The report advocates a procedure for evaluation of forensic evidence that is a two-stage procedure in which the first stage is "match"/"non-match" and the second stage is empirical assessment of sensitivity (correct acceptance) and false alarm (false acceptance) rates. Almost always, quantitative data from feature-comparison methods are continuously-valued and have within-source variability. We explain why a two-stage procedure is not appropriate for this type of data, and recommend use of statistical procedures which are appropriate.

Adventitious match probability for autosomal profiles when primer binding site mutation is possible.

This paper considers the situation where two DNA systems with differing primers have been used to produce DNA profiles for loading and searching of a DNA Database. With any profiling system there exists the possibility of a "primer binding site mutation" (PBSM). When such a mutation occurs at one of the loci in a profile, it has the effect that the associated allele is not visible in the profile. In the case where a person has two different alleles at a given locus (heterozygous) the effect of a PBSM would be that the profile would appear to be that of an individual with only one allele at that locus (homozygous). The paper investigates the potential for an adventitious match as a result of a PBSM when, for example, a crime profile and person profile that have originated from two different individuals are found to be the same as a result of a PBSM in one of the profiles. It is demonstrated, both by theory and using simulations, that the effect of PBSMs is to slightly decrease the adventitious match probability from what it would had the same DNA system been used.

A potential role for family members in mental health care delivery: the family community navigation specialist.

OBJECTIVE: Opening Doors to Recovery (ODR) in southeast Georgia included a family community navigation specialist (F-CNS) in addition to a peer specialist and a mental health professional. This qualitative study assessed the usefulness of the F-CNS role. METHODS: Semistructured interviews were conducted with 30 respondents (ten ODR participants with serious mental illnesses; ten family members; and ten ODR leaders and team members, including two F-CNSs). Interviews were recorded and transcribed for qualitative analysis. RESULTS: Many respondents found the F-CNS to be helpful, providing psychosocial support, serving as a communication liaison, and being a team member dedicated to the family. Aspects that might require improvement include insufficient description of the F-CNS role to participants and the limited experience and training of the F-CNSs. CONCLUSIONS: The F-CNS represents an unexplored role for family members of persons with serious mental illnesses that may complement the roles of other service providers and strengthen recovery-oriented teams.

General nurses' perceptions of palliative care.

Although considerable progress has been made in treating cancer, it is suggested that, even at diagnosis, attempts at cure may sometimes be unrealistic. As a result, many patients may require palliative care on general hospital wards, and how general nurses understand or interpret the goals of palliative care may determine, at least in part, the care they provide. This qualitative, exploratory study attempted to develop an understanding of the perceptions of general nurses towards palliative care. Findings indicate that this sample of nurses focused primarily on the disease and that which the patient had 'lost', regarding him/her not as a living person but as a dying patient. The nurses' role is seen to be that of 'taking over' all activities for the patient, so as to reduce suffering. The importance of maintaining quality of life and the need to respect patients' wishes are recognised, although it appears that nurses often assume that they 'know' what is best. Although the nurses exhibited considerable commitment to providing the best possible care, their predominant perception of the patient as dying determined the interventions selected. This preoccupation with dying may prevent them from helping the patient to live a full life until the time of death.

Evaluation of mental health first aid training in a diverse community setting.

Mental health first aid (MHFA) training has been disseminated in the community and has yielded positive outcomes in terms of increasing help-seeking behaviour and mental health literacy. However, there has been limited research investigating the effectiveness of this programme in multicultural communities. Given the increasing levels of multiculturalism in many countries, as well as the large number of barriers presented to these groups when trying to seek help for mental illnesses, the present study aimed to investigate the effectiveness of MHFA in these settings. A total of 458 participants, who were recruited from multicultural organizations, participated in a series of MHFA training courses. Participants completed questionnaires pre and post the training course, and 6-month follow-up interviews were conducted with a subsample of participants. Findings suggested that MHFA training increased participant recognition of mental illnesses, concordance with primary care physicians about treatments, confidence in providing first aid, actual help provided to others, and a reduction in stigmatizing attitudes. A 6-month follow up also yielded positive long-term effects of MHFA. The results have implications for further dissemination and the use of MHFA in diverse communities. In addition, the results highlight the need for mental health training in health-care service providers.

Evaluating forensic DNA profiles using peak heights, allowing for multiple donors, allelic dropout and stutters.

Increases in the sensitivity of DNA profiling technology now allow profiles to be obtained from smaller and more degraded DNA samples than was previously possible. The resulting profiles can be highly informative, but the subjective elements in the interpretation make it problematic to achieve the valid and efficient evaluation of evidential strength required in criminal cases. The problems arise from stochastic phenomena such as "dropout" (absence of an allele in the profile that is present in the underlying DNA) and experimental artefacts such as "stutter" that can generate peaks of ambiguous allelic status. Currently in the UK, evidential strength evaluation uses an approach in which the complex signals in the DNA profiles are interpreted in a semi-manual fashion by trained experts aided by a set of guidelines, but also relying substantially on professional judgment. We introduce a statistical model to calculate likelihood ratios for evaluating DNA evidence arising from multiple known and unknown contributors that allows for such stochastic phenomena by incorporating peak heights. Efficient use of peak heights allows for more crime scene profiles to be reported to courts than is currently possible. The model parameters are estimated from experimental data incorporating multiple sources of variability in the profiling system. We report and analyse experimental results from the SGMPlus system, run at 28 amplification cycles with no enhancements, currently used in the UK. Our methods are readily adapted to other DNA profiling systems provided that the experimental data for the parameter estimation is available.