A carregar...
53 resultados
Resultados da pesquisa
A mostrar 1 - 10 de 53
- Imigração em Portugal: contributo dos polimorfismos genéticos para a investigação de parentesco entre supostos familiaresPublication . Carvalho, Mónica; Vieira Da Silva, Cláudia; Dourado, Catarina; Dario, Paulo; Reis, Fátima; Rodrigues, Diogo; Porto, Maria João; Ribeiro, TeresaA solicitação de investigações de parentesco inseridas em processos de imigração, nomeadamente os relacionados com indivíduos que pretendem obter títulos de residência em Portugal, têm vindo a aumentar nos últimos anos no Serviço de Genética e Biologia Forenses da Delegação do Sul (SGBF S) O problema levanta se quando existe um familiar que já reside em Portugal, o qual pretende que outros familiares venham a residir também em Portugal e são apresentados documentos cuja veracidade é posta em causa Neste trabalho, apresentamos um caso em que o Ministério Público pretende confirmar a relação de parentesco biológico existente entre um determinado indivíduo e os seus três filhos registrais do sexo masculino,sendo que apenas dois deles são filhos da mesma mulher
- South Portugal population genetic analysis with 17 loci STRsPublication . Vieira da Silva, Cláudia; Cruz, C.; Ribeiro, Teresa; Espinheira, R.STRs are the standard genetic markers mainly used in forensic cases. In routine casework it is important to establish a population genetic database for further reliable statistical analyses. AmpF1STRIdentifiler (Applied Biosystems) and Geneprint Powerplex 16 (Promega Corporation, Madison WI, USA) are multiplex kits wich co-amplifie 17 STR - loci including the segment of X-Y homologous gene Amelogenina routinely used in our laboratory. 13 core short tandem repeat loci standardized under the combined DNA Index System (Codis): CSF1PO, D3S1358, D5S818, D13S317, D16S539, D18S51, D21S11, vWA, FGA, TH01, TPOX, two additional tetranucleotide loci - D2S1338 and D19S433 – and two additional pentanucleotides – Penta E and Penta D. The purpose of this study is to determine the allele distribution data of the 17 STR loci in 2445 caucasian unrelated individuals from the south of Portugal, 176 unrelated individuals from Cabo Verde and 102 unrelated individuals from Angola and compare it with the values of the all the population resident in the same area. Allele frequencies for each locus observed heterozygosity, expected heterozygosity, power of exclusion, power of discrimination, and p values of chi-square test for departures from Hardy-Weinberg expectations were calculated.
- Insertion/Delection Polymorphism and forensic aplications: A preliminary studyPublication . Vieira Da Silva, Cláudia; Matos, Sara; Amorim, António; Afonso Costa, Heloísa; Morais, Paulo; Santos, Rodolfo; Espinheira, Rosa; Santos, J. CostaThe human genetic identification is usually based on the study of STR markers, robust and reliable for samples containing relatively small quantities of DNA. Recent advances in forensic genetics have focused on the development of genotyping assays using shorter amplicons, in order to improve the successful amplification of degraded samples. Single Nucleotide Polymorphisms (SNP) and Insertion/Deletion polymorphisms (INDEL), length polymorphisms created by insertions or deletions of one or more nucleotides in the genome, have considerable potential in this kind of forensic samples, usually present in identification casework, since they can combine desirable characteristics of both, STR and SNP. In this study, a set of 30 biallelic Deletion/Insertion polymorphisms (DIP or INDEL) distributed over 19 autosomes plus Amelogenin in a single multiplex PCR reaction was applied to 100 healthy and unrelated caucasian individuals. Statistical analysis revealed that the 30 biallelic markers can provide satisfactory levels of informativeness for forensic demands.
- Necessidade de exumação em investigação de paternidadePublication . Ribeiro, Teresa; Eiras, Luisa; Dario, Paulo; Lucas, Isabel; Vieira Da Silva, Cláudia; Espinheira, Rosa
- Forensic genetic analysis of South Portuguese population with the six dye Powerplex® Fusion 6CPublication . Vieira Da Silva, Cláudia; Afonso Costa, Heloísa; Porto, Maria João; Cunha, E; Corte Real, F.; Amorim, AntónioAs an improvement in efficiency and in Human Discrimination Power, the new six dye multiplex kit PowerPlex® Fusion 6C System, by Promega, available for human identification can co-amplify 27 loci, in a single reaction, have been introduced in the last years with great success. This kit allows the amplification and detection of autosomal loci included in the expanded Combined DNA Index System CODIS, plus the loci Penta D, PENTA E and SE33 as well as Amelogenin for gender determination. Furthermore, this kit includes three Y –STRs (DYS391, DYS576 and DYS570), allowing allelic attribution in a total of 27 loci. This genetic markers extension satisfies not only CODIS but also European Standard Set recommendations. Thinking about continuous human migration movements, especially in a very cosmopolitan region like Lisbon and south of Portugal, and also, in keeping population studies and actualized STR databases we decided to update our previous studies. Our sample is composed of 600 unrelated individuals, from paternity testing with laboratory identity anonymised. DNA was extracted by Prep-n-go BufferTM(Thermo-Fisher Scientific). PCR amplification was performed with PowerPlex® Fusion 6C System, according to manufacturer’s guidelines. Fragment analysis was carried out in an Applied Biosystems® 3500 Genetic Analyser. Electrophoresis results were analysed with GeneMapper® ID-X v1.4. Allele frequencies and population statistics, including Hardy-Weinberg equilibrium p-values from exact test probabilities and forensic parameters were calculated with adequate software. In conclusion, our population information was updated in order to apply most recent data in our casework weight of evidence.
- Identificação genética a partir de lâminasPublication . Ribeiro, Teresa; Vieira da Silva, Cláudia; Lucas, Isabel; Dario, Paulo; Geada, Helena; Espinheira, Rosa
- Population Genetic Data for F13A01, FES/FPS, F13B and LPL in the South Portuguese PopulationPublication . Vieira da Silva, Cláudia; Amorim, António; Afonso Costa, Heloísa; Espinheira, Rosa; Costa Santos, JorgeDNA parentage testing is currently performed using several highly polymorphic short tandem repeats (STRs). In our routine casework, we apply two validated STRs kits, in order to have results in the 13 codis loci plus D2S1338, D19S433, PENTA E, PENTA D, and Amelogenin. In complex and deficient paternity cases it is often necessary to increment the number of studied STRs. For this reason, we introduced in our laboratory GenePrint® FFFL Multiplex kit, which can provide results in F13A1, FES/FPS, F13B, and LPL using the GenePrint® FFFL System (Promega, USA) kit. In this study, we analyzed 150 unrelated and healthy individuals from the south Portugal population. Allele frequencies and statistical parameters were estimated with Arlequin 3.5.1.2. Paternity Statistics were calculated using software package PowerStats v12. The forensic efficiency values suggested that loci F13A01, FES/FPS, F13B, and LPL are discriminative and very useful to solve complex forensic casework, and should be added to the set of STRs loci routinely used in Forensic laboratories. In conclusion, an additional 4 loci dataset was established for the south Portuguese population, which can be used for both forensic casework and complex kinship testing
- QUANTIFILER®TRIO DNA method performance in a collection of ancient samplesPublication . Vieira- Silva, C.; Lopes, J.; Afonso Costa, H.; Ribeiro, T.; Porto, M.J.; Dias, M; Cunha, E; Amorim, A,During the past few years significant progress has been made in solving technical challenges associated with STR profiling including the ability to analyze degraded DNA and low amounts of DNA. The result of these changes is that useful STR profiles can now be obtained from previously untypeable forensic DNA samples. Analysis of DNA from ancient material represents an important role in molecular anthropology, although there are many limitations concerning low DNA quantity and/or degraded DNA, and/or PCR inhibitors. These factors can make it difficult to decide whether to continue with STR analysis, which STR panel to use and how much DNA to add to PCR reaction. With all these constraints, DNA quantification represents an important tool to decide which method will follow in order to improve workflow and have good results in less time-consuming. The Quantifiler® Trio DNA method provides a quality index (QI) to detect the presence of degraded DNA along with PCR inhibitors.This guide allows the selection of the optimal short tandem repeat (STR) analysis chemistry (autosomal, or miniSTR) and streamlines the workflow while increasing downstream analysis success rates. In order to compare DNA quality from different extraction methods, samples from 46 exhumed Middle Ages individuals were extracted with modified phenol-chloroform method and also PrepFiler Express BTA™ method. DNA was quantified with Quantifiler® Trio DNA Quantification in an Applied Biosystems® 7500 Real-Time PCR System. Results were analyzed and allow us to point Quantifiler® Trio method as an important tool in pre-STR typing methods in ancient samples
- Forensic Genetics as a Tool for Peace and Justice: An Overview on DNA QuantificationPublication . Vieira Da Silva, Cláudia; Afonso Costa, Heloísa; Costa Santos, J.; Espinheira, RosaIn Forensic Genetics, DNA analysis is performed to obtain a Short Tandem Repeat (STR) profile from an evidence sample, which is then compared with the victim and suspect(s) reference sample STR profile, to determine their contribution to that evidence sample. However, forensic biological samples can be present in low quantities and be exposed to different environmental insults leading to DNA degradation and contamination by inhibitor compounds. Thus, it is desirable for a forensic scientist to have useful information about the forensic sample quantity and quality prior to STR amplification. New methods in Forensic DNA analysis for detecting, preserving, and quantifying DNA, as well as its recovery from different biological materials are continually being developed. Real-Time PCR (RT-PCR) assays for DNA quantification, like the recent Quantifiler® Duo DNA quantification kit (Applied Biosystems) proved to be very useful in forensic samples. Since many samples, mainly those resulting from sexual assault cases are often composed by unbalanced male/female DNA mixtures, the knew RT-PCR quantification assay, developed to quantify relative male/ female DNA ratio contributes not only to total DNA determination but also to ascertain the presence and quantity of enough male DNA in the sample. These results are important to guide the optimal STR analysis selection, such as autosomal STR, Y-STR, or mini-STR, increasing downstream analysis success rates. In this work we present real forensic casework where the DNA amount and quality were important to guide the selection of the appropriate STR amplification kit in order to increase the success of profiling in the first attempt, reducing the number of samples that need to be reprocessed and thereby decreasing the turn around time in a forensic laboratory.
- Y-Filer Plus® genetic characterization of caucasian individuals from South PortugalPublication . Vieira da Silva, Cláudia; Afonso Costa, Heloísa; Proença, Marta; Ribeiro, Teresa; Porto, Maria João; Amorim, AntónioDue to their paternal inheritance, Y-STRs offers particular perspectives for identification and kinship analysis and are also a precious tool in sexual assault cases with relatively high amount of female DNA and also in mixtures from multiple male donors. Nonetheless their value, there are some limitations to their use in forensic investigations since their ability to discriminate between individuals is considerably lower than that of the autosomal STRs set, mainly in cases with close or distant patrilineal relatives.One of the most recently developed Y-STR kit, Y-Filer Plus® (Life Technologies, Foster city, USA), allows forensic geneticists to study 27 Y-chromosomal loci. All the 16 markers included in the Y-Filer® kit (Life Technologies, Foster city, USA), plus 9 additional markers: DYS576, DYS627, DYS460, DYS518, DYS570, DYS449, DYS481, DYF387S1 and DYS533, six of which (DYS576, DYS627, DYS518, DYS570, DYS449 and DYF387S1) are characterized as “rapidly mutating”, and can differentiate between unrelated individuals and possibly between male relatives.Allelic frequencies were estimated with Arlequin v. 3.5. Gene and Haplotype diversities were estimated according to Nei formula. The discrimination capacity was also calculated by dividing the number of different haplotypes by the total number of individuals in the sample. The fraction of unique haplotypes was determined as the percent proportion of unique haplotypes. In conclusion, the recently introduced Y-Filer Plus® system provides innovative discriminatory power for forensic application