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The Spanish and Portuguese-Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) has organized a second collaborative exercise on a simulated case of Disaster Victim Identification (DVI), with the participation of eighteen laboratories. The exercise focused on the analysis of a simulated plane crash case of medium-size resulting in 66 victims with varying degrees of fragmentation of the bodies (with commingled remains). As an additional difficulty, this second exercise included 21 related victims belonging to 6 families among the 66 missings to be identified. A total number of 228 post-mortem samples were represented with aSTR and mtDNA profiles, with a proportion of partial aSTR profiles simulating charred remains. To perform the exercise, participants were provided with aSTR and mtDNA data of 51 reference pedigrees -some of which deficient-including 128 donors for identification purposes. The exercise consisted firstly in the comparison of the post-mortem genetic profiles in order to re-associate fragmented remains to the same individual and secondly in the identification of the re-associated remains by comparing aSTR and mtDNA profiles with reference pedigrees using pre-established thresholds to report a positive identification. Regarding the results of the post-mortem samples re-associations, only a small number of discrepancies among participants were detected, all of which were from just a few labs. However, in the identification process by kinship analysis with family references, there were more discrepancies in comparison to the correct results. The identification results of single victims yielded fewer problems than the identification of multiple related victims within the same family groups. Several reasons for the discrepant results were detected: a) the identity/non-identity hypotheses were sometimes wrongly expressed in the likelihood ratio calculations, b) some laboratories failed to use all family references to report the DNA match, c) In families with several related victims, some laboratories firstly identified some victims and then unnecessarily used their genetic information to identify the remaining victims within the family, d) some laboratories did not correctly use "prior odds" values for the Bayesian treatment of the episode for both post-mortem/post-mortem re-associations as well as the ante-mortem/post-mortem comparisons to evaluate the probability of identity. For some of the above reasons, certain laboratories failed to identify some victims. This simulated "DNA-led" identification exercise may help forensic genetic laboratories to gain experience and expertize for DVI or MPI in using genetic data and comparing their own results with the ones in this collaborative exercise., (Copyright © 2021 Elsevier B.V. All rights reserved.)

One of the main goals of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the field of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, six exercises have been organized. At the present edition (GHEP-MIX06), with 25 participant laboratories, the exercise main aim was to assess mixture profiles results by issuing a report, from the proposal of a complex mock case. One of the conclusions obtained from this exercise is the increasing tendency of participating laboratories to validate DNA mixture profiles analysis following international recommendations. However, the results have shown some differences among them regarding the edition and also the interpretation of mixture profiles. Besides, although the last revision of ISO/IEC 17025:2017 gives indications of how results should be reported, not all laboratories strictly follow their recommendations. Regarding the statistical aspect, all those laboratories that have performed statistical evaluation of the data have employed the likelihood ratio (LR) as a parameter to evaluate the statistical compatibility. However, LR values obtained show a wide range of variation. This fact could not be attributed to the software employed, since the vast majority of laboratories that performed LR calculation employed the same software (LRmixStudio). Thus, the final allelic composition of the edited mixture profile and the parameters employed in the software could explain this data dispersion. This highlights the need, for each laboratory, to define through internal validations its criteria for editing and interpreting mixtures, and to continuous train in software handling., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A collaborative effort was carried out by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) to promote knowledge exchange between associate laboratories interested in the implementation of indel-based methodologies and build allele frequency databases of 38 indels for forensic applications. These databases include populations from different countries that are relevant for identification and kinship investigations undertaken by the participating laboratories. Before compiling population data, participants were asked to type the 38 indels in blind samples from annual GHEP-ISFG proficiency tests, using an amplification protocol previously described. Only laboratories that reported correct results contributed with population data to this study. A total of 5839 samples were genotyped from 45 different populations from Africa, America, East Asia, Europe and Middle East. Population differentiation analysis showed significant differences between most populations studied from Africa and America, as well as between two Asian populations from China and East Timor. Low F ST values were detected among most European populations. Overall diversities and parameters of forensic efficiency were high in populations from all continents., (Copyright © 2017 Elsevier B.V. All rights reserved.)

DNA is a powerful tool available for forensic investigations requiring identification of species. However, it is necessary to develop and validate methods able to produce results in degraded and or low quality DNA samples with the high standards obligatory in forensic research. Here, we describe a voluntary collaborative exercise to test the recently developed Species Identification by Insertions/Deletions (SPInDel) method. The SPInDel kit allows the identification of species by the generation of numeric profiles combining the lengths of six mitochondrial ribosomal RNA (rRNA) gene regions amplified in a single reaction followed by capillary electrophoresis. The exercise was organized during 2014 by a Working Commission of the Spanish and Portuguese-Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG), created in 2013. The 24 participating laboratories from 10 countries were asked to identify the species in 11 DNA samples from previous GHEP-ISFG proficiency tests using a SPInDel primer mix and control samples of the 10 target species. A computer software was also provided to the participants to assist the analyses of the results. All samples were correctly identified by 22 of the 24 laboratories, including samples with low amounts of DNA (hair shafts) and mixtures of saliva and blood. Correct species identifications were obtained in 238 of the 241 (98.8%) reported SPInDel profiles. Two laboratories were responsible for the three cases of misclassifications. The SPInDel was efficient in the identification of species in mixtures considering that only a single laboratory failed to detect a mixture in one sample. This result suggests that SPInDel is a valid method for mixture analyses without the need for DNA sequencing, with the advantage of identifying more than one species in a single reaction. The low frequency of wrong (5.0%) and missing (2.1%) alleles did not interfere with the correct species identification, which demonstrated the advantage of using a method based on the analysis of multiple loci. Overall, the SPInDel method was easily implemented by laboratories using different genotyping platforms, the interpretation of results was straightforward and the SPInDel software was used without any problems. The results of this collaborative exercise indicate that the SPInDel method can be applied successfully in forensic casework investigations., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Communicating and interpreting genetic evidence in the administration of justice is currently a matter of great concern, due to the theoretical and technical complexity of the evaluative reporting and large difference in expertise between forensic experts and law professionals. A large number of initiatives have been taken trying to bridge this gap, contributing to the education of both parties. Results however have not been very encouraging, as most of these initiatives try to cope globally with the problem, addressing simultaneously theoretical and technical approaches which are in a quite heterogeneous state of development and validation. In consequence, the extension and complexity of the resulting documents disheartens their study by professionals (both jurists and geneticists) and makes a consensus very hard to reach even among the genetic experts' community. Here we propose a 'back-to-basics', example-driven approach, in which a model report for the two most common situations faced by forensic laboratories is presented. We do hope that this strategy will provide a solid basis for a stepwise generalisation., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

One of the main objectives of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the area of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, three exercises have been organized (GHEP-MIX01, GHEP-MIX02 and GHEP-MIX03), with 32, 24 and 17 participant laboratories respectively. The exercise aims to give a general vision by addressing, through the proposal of mock cases, aspects related to the edition of mixture profiles and the statistical treatment. The main conclusions obtained from these exercises may be summarized as follows. Firstly, the data show an increased tendency of the laboratories toward validation of DNA mixture profiles analysis following international recommendations (ISO/IEC 17025:2005). Secondly, the majority of discrepancies are mainly encountered in stutters positions (53.4%, 96.0% and 74.9%, respectively for the three editions). On the other hand, the results submitted reveal the importance of performing duplicate analysis by using different kits in order to reduce errors as much as possible. Regarding the statistical aspect (GHEP-MIX02 and 03), all participants employed the likelihood ratio (LR) parameter to evaluate the statistical compatibility and the formulas employed were quite similar. When the hypotheses to evaluate the LR value were locked by the coordinators (GHEP-MIX02) the results revealed a minor number of discrepancies that were mainly due to clerical reasons. However, the GHEP-MIX03 exercise allowed the participants to freely come up with their own hypotheses to calculate the LR value. In this situation the laboratories reported several options to explain the mock cases proposed and therefore significant differences between the final LR values were obtained. Complete information concerning the background of the criminal case is a critical aspect in order to select the adequate hypotheses to calculate the LR value. Although this should be a task for the judicial court to decide, it is important for the expert to account for the different possibilities and scenarios, and also offer this expertise to the judge. In addition, continuing education in the analysis and interpretation of mixture DNA profiles may also be a priority for the vast majority of forensic laboratories., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

There has been very little work published on the variation of reporting practices of mixtures between laboratories, but it has been previously demonstrated that there is little consistency. This is because there is no current uniformity of practice, so different laboratories will operate using different rules. The interpretation of mixtures is not solely a matter of using some software to provide 'an answer'. An assessment of a case will usually begin with a consideration of the circumstances of a crime. Assumptions made about the numbers of contributors follow from an examination of the electropherogram(s)--and these may differ between the prosecution and the defence hypotheses. There may be a necessity to evaluate several sets of hypotheses for any given case if the circumstances are uncertain. Once the hypotheses are formulated, the mathematical analysis is complex and can only be accomplished by the use of specialist software. In order to obtain meaningful results, it is essential that scientists are trained, not only in the use of the software, but also in the methodology to understand the likelihood ratio concept that is used. The Euroforgen-NoE initiative has developed a training course that utilizes the LRmix program to carry out the calculations. This software encompasses the recommendations of the ISFG DNA commissions on mixture interpretation and is able to interpret samples that may come from two or more contributors and may also be partial profiles. Recently, eighteen different laboratories were trained in the methodology. Afterwards they were asked to independently analyze two different cases with partial mixture DNA evidence and to write a statement court-report. We show that by introducing a structured training programme, it is possible to demonstrate, for the first time, that a high degree of standardization, leading to uniformity of results can be achieved by participating laboratories., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

The GHEP-ISFG Working Group performed a collaborative exercise to monitor the current practice of mitochondrial (mt)DNA reporting. The participating laboratories were invited to evaluate a hypothetical case example and assess the statistical significance of a match between the haplotypes of a case (hair) sample and a suspect. A total of 31 forensic laboratories participated of which all but one used the EMPOP database. Nevertheless, we observed a tenfold range of reported LR values (32-333.4), which was mainly due to the selection of different reference datasets in EMPOP but also due to different applied formulae. The results suggest the need for more standardization as well as additional research to harmonize the reporting of mtDNA evidence., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)