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- Got her mummy´s eyes: Eye color investigation using IrisPlex – preliminary studyPublication . Dario, Paulo; Rita Olivera, Ana; Ribeiro, Teresa; Lucas, Isabel; Marques, Manuela; Porto, Maria João; Costa Santos, Jorge; Corte Real, F.; Dias, DeodáliaSNP phenotypic markers are being studied by several groups worldwide. As a result, phenotypic loci such as the ones responsible for human eye, hair and skin color are starting to get known. These may provide information for identification of unknown sample donors in criminal casework when there are no suspects. This kind of information may be even more relevant when the sample donor possesses phenotypic characteristics which distinguish him from the population in which he is inserted. Nevertheless, this approach may be used in similar scientific areas. In this work, a DNA sample from a mummified corpse with historical and scientific interest was studied in order to discover more information about who this corps belonged to. One of the tools used in this investigation was IrisPlex, designed for eye color prediction. This study presents one example on how this methodologies may be useful, not only in forensic investigation but also in areas such as physical anthropology.
- O que dizem os teus olhos? Investigação de características fenotípicas em peça museológica e perspetiva de uso futuro em Genética ForensePublication . Dario, Paulo; Olivera, Ana Rita; Ribeiro, Teresa; Lucas, Isabel; Marques, Manuela; Porto, Maria João; Costa Santos, Jorge; Dias, Deodália; Corte Real, F.Os marcadores fenotípicos, do tipo SNP, têm vindo a ser estudados por vários grupos a nível mundial, pelo que começam a ser conhecidos marcadores para características fenotípicas não só para a cor dos olhos, mas também para a cor do cabelo e pele, os quais podem fornecer um conjunto valioso de informação para a identificação do dador da amostra em estudo. Este tipo de informação poderá ser tanto mais relevante se o dador da amostra possuir características fenotípicas que o distingam da população na qual se encontra inserido. Neste trabalho, foi estudada uma amostra de uma peça museológica com interesse histórico-científico que exemplifica como este tipo de novas metodologias poderá ter interesse em áreas como a investigação criminal ou como a antropologia física.
- Internal Validation of the Investigator 26Plex QS Amplification Kit: a high-throughput multiplex assay for reference and low copy number DNA samplesPublication . Cardoso, Paula; Serra, Armando; Bogas, Vanessa; Balsa, Filipa; Lopes, Virginia; Dario, Rita; Porto, Maria João; Amorim, António; Corte Real, F.; Brito, PedroThe Investigator® 26plex QS Amplification Kit, from QIAGEN, provides reliable and rapid DNA profiles while enabling the multiplex amplification of 24 STRs, 2 Quality Sensors and a gender-determining marker, Amelogenin. The Quality Sensors incorporated in this kit provide insight into the sample quality and the PCR's success while alerting to the presence of inhibitors. Through an extensive internal validation study, this research sought to implement the Investigator® 26plex QS in the laboratory routine of the Forensic Genetic and Biology Service, Central branch (SGBF-C) of the Portuguese National Institute of Legal Medicine and Forensic Sciences. Here we detail the procedures and parameters applied which followed the SWGDAM guidelines, as well as report the results obtained throughout. Firstly, it was crucial to establish unique analytical criteria that would be the baseline for the interpretation of the results obtained. To accomplish such, analytical, stochastic, heterozygous balance and stutter thresholds were defined. Thereupon, this study intended to gauge the kit’s performance, by evaluating its concordance with normalized methodologies while assessing its sensitivity, specificity, robustness, and precision, besides its efficiency in the presence of degraded and/or inhibited samples. Lastly, in favour of optimizing the laboratory workflow, an assay was carried out to test half volume reactions and direct amplification on reference samples. In this study a wide range of sample types were analysed, which made it possible to acquire robust data pertaining to the performance of the assay. The laboratory methodology applied comprehended: DNA extraction using Prep-n-Go™ Buffer and PrepFiler Express™ Forensic DNA Extraction Kit, quantification with the Quantifiler™ Trio Quantification Kit, followed by the amplification with the Investigator® 26plex QS. Capillary electrophoresis was performed in the Applied Biosystems™ 3500 Genetic Analyzer, and the electropherograms’ were analysed using the GeneMapper™ ID-X Software v1.6. Through this work, it was possible to characterize the main advantages of the Investigator® 26plex QS kit, as well as its limitations. The validation data demonstrated that this system produces reliable profiles in the presence of minute DNA quantities and identifies the minor contributor in a mixture up to a 1:50 ratio. The results inferred a high human specificity, robustness, and sensitivity, while producing concordant and reproducible results with optimized protocols for both reference and low copy number DNA samples. Through concordance studies it was further shown that there is a high consistency between this novel amplification kit and those currently implemented in the SGBF-C, thus proving its suitability for the analysis of forensic samples.