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Prieto L.,University Institute of Research in Forensic science | Alves C.,University of Porto | Zimmermann B.,Innsbruck Medical University | Tagliabracci A.,Marche Polytechnic University | And 29 more authors.
Forensic Science International: Genetics | Year: 2013

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. © 2012 Elsevier Ireland Ltd. Source


Montesino M.,University Institute of Research in Forensic science | Tagliabracci A.,Marche Polytechnic University | Zimmermann B.,Innsbruck Medical University | Gusmao L.,University of Porto | And 29 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2011

In this GHEP-ISFG exercise, participating labs were invited to evaluate a forensic case in which the mtDNA haplotype from a hair shaft in the victim's hand matched the suspect's haplotype. 31 forensic labs participated in the exercise. Although all except one used the EMPOP database to estimate the haplotype frequencies different final likelihood ratios (LRs) were reported. The main factors affecting these differences were: the origin of the reference population, the approaches to correct sampling errors, the LR formula, the source of EMPOP data (forensic/literature), the type of search (pattern or literal and "disregard Indels" option) and the selected edition range to perform the queries. This demonstrates that further efforts are needed in order to standardize the statistical evaluation of the mtDNA evidence. © 2011 Elsevier Ireland Ltd. Source


Prieto L.,University Institute of Research in Forensic science | Zimmermann B.,Innsbruck Medical University | Goios A.,University of Porto | Rodriguez-Monge A.,University Institute of Research in Forensic science | And 17 more authors.
Forensic Science International: Genetics | Year: 2011

Mitochondrial DNA (mtDNA) population data for forensic purposes are still scarce for some populations, which may limit the evaluation of forensic evidence especially when the rarity of a haplotype needs to be determined in a database search. In order to improve the collection of mtDNA lineages from the Iberian and South American subcontinents, we here report the results of a collaborative study involving nine laboratories from the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) and EMPOP. The individual laboratories contributed population data that were generated throughout the past 10 years, but in the majority of cases have not been made available to the scientific community. A total of 1019 haplotypes from Iberia (Basque Country, 2 general Spanish populations, 2 North and 1 Central Portugal populations), and Latin America (3 populations from São Paulo) were collected, reviewed and harmonized according to defined EMPOP criteria. The majority of data ambiguities that were found during the reviewing process (41 in total) were transcription errors confirming that the documentation process is still the most error-prone stage in reporting mtDNA population data, especially when performed manually. This GHEP-EMPOP collaboration has significantly improved the quality of the individual mtDNA datasets and adds mtDNA population data as valuable resource to the EMPOP database (www.empop.org). © 2010 Elsevier Ireland Ltd. Source


Martinez P.,National Institute of Toxicology and Forensic Science INTCF | Santiago B.,National Institute of Toxicology and Forensic Science INTCF | Alcala B.,National Institute of Toxicology and Forensic Science INTCF | Atienza I.,National Institute of Toxicology and Forensic Science INTCF
Science and Justice | Year: 2015

Sexual assault cases have varying factors that may mask semen findings when analysing evidence at the forensic laboratory. Semenogelin (Sg) is a potential marker for the identification of semen even at azoospermy or when few sperm cells are found. The current study examined Sg in normospermic and azoospermic donors as an internal evaluation of sensitivity, specificity and interference. The impact of a historical review of 53 judicial sexual assault cases over a five-year period was also analysed. The use of varying tests was of importance to prioritize certain samples within cases. Semen findings by Sg were then compared to prostate-specific antigen (PSA), phosphatase enzyme (AP) and Y-chromosome presence, the latter being used in an attempt to link semen fluid identification with obtaining a male DNA profile. Test findings were the highest ever registered for Sg (1:400,000), PSA (1:800,000), AP (1:25,000) and sperm cytology (SC) (1:50,000). Our results demonstrated the usefulness of using the Sg marker to avoid a false semen-negative result (6% cases), particularly in cases where sperm was absent or scarce (11% spermatozoa positive cases). Results were expressed in categories according to the set: Sg-PSA-AP. Thus, categories I (full positive, 46%), VI (full negative, 27%) and III (Sg/PSA positive; 11%) were the most frequent and Y-chromosome was obtained in 59%, 12% and 12% ratios, respectively. In conclusion, Sg was recommended for the workflow procedure of semen investigation when sperm absence is expected either from azoospermic/oligospermic or normospermic semen, especially before/after ejaculation. © 2015 Forensic Science Society. Source


Fernandez K.,National Institute of Toxicology and Forensic Science INTCF | Gomez J.,National Institute of Toxicology and Forensic Science INTCF | Garcia-Hirschfeld J.,National Institute of Toxicology and Forensic Science INTCF | Cubillo E.,National Institute of Toxicology and Forensic Science INTCF | And 2 more authors.
Forensic Science International: Genetics Supplement Series | Year: 2015

Since 1992, it has been organized annually in Spain, a Forensic Intercomparison Exercise coordinated by the Madrid Department of the National Institute of Toxicology and Forensic Sciences (INTCFM) and organized by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG). The need to improve and assure the quality of our services as well as to demonstrate our competence, led us to accredit this Exercise under ISO/IEC 17043. This International Standard ensures quality of proficiency testing providers regarding technical and management requirements. In this work, we present the step-wise process we began in 2011 focused on upgrading the Basic level of the Intercomparison Exercise towards its accreditation, which was successfully achieved in December 2014. All adjustments made are described. From the early structural changes, since the Exercise had to be divided in two levels, passing through the definition of the scope, to the technical improvements made and management policy implementation. © 2015 Elsevier Ireland Ltd. Source

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