Browsing by Author "Espinheira, Rosa"
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- Analysis of NGM STR loci in South Portuguese PopulationPublication . Ribeiro, Teresa; Dario, Paulo; Vital, Nádia; Sanches, Susana; Espinheira, Rosa; Geada, Helena; Costa Santos, JorgeAllele frequencies and other relevant forensic parameters of 15 loci studied with Applied Biosystems AmpFlSTRs NGM Kit were calculated in a population of individuals residing in the South of Portugal. Blood stain samples were obtained from a total of 350 unrelated individuals involved in paternity testing casework. This new kit has five loci not present in any other kit used in our laboratory (Promega Powerplex 16 System and Applied Biosystems Identifiler Plus): D10S1248, D22S1045, D2S441, D1S1656 and D12S391. The NGM multiplex kit is used in our forensic casework as an auxiliary screening tool to solve deficient casework such as fatherless paternity testing, and to help in paternity investigations with one genetic incompatibility after the routine seventeen loci typing. Furthermore, this five loci included in the European Standard Set are also recommended by the European Network of Forensic Science Institutes (ENFSI) and the European DNA Profiling group (EDNAP). These studies are necessary to calculate statistical forensic parameters such as power of discrimination, power of exclusion or minimum allele frequencies. Statistical parameters such as heterozigoty, homozigoty or allele frequencies were determined with Arlequim V3.5 and results compared with the ones reported in previous similar studies. As final remark, is important to remember that this kind of study is highly important for the Forensic Laboratories accreditation achievement
- Biological Evidences and Sexual Assault in Forensic MedicinePublication . Vieira, Claudia; Lucas, Isabel; Ribeiro, Teresa; Costa Santos, J.; Espinheira, RosaIntroduction Sexual assault crimes are ubiquitous; usually unwitnessed, so victim’s statements may be the only direct evidence that it has occurred. Medical examination and biological samples collection are of inequivocal importance. Presence of spermatozoa in smears, elevated acid phosphatase and the presence of Y-STR profiler in the victim’s evidence’s, could be crucial to corroborate victim’s testimony. The Y chromosome is far the most important scientific evidence, not only due to it’s gender specificity and easy amplification in a male/female mixtures, but also because it can easily contribute for the number of unrelated male contributor’s estimation in an biological evidence. The aim of this study is to ascertain a few characteristics concerning sexual harassment and a Y-haplotype profile obtention, which may help to prove or disprove a link between individuals and objects or places. Methodology Biological samples from 782 sexual assault cases were studied. Glass slide vaginal and anal smears were stained with Papanicolau’s and Harris Hematoxilin Solution. For the phosphatase test, a commercially available test paper strip was used (Phosphatesmo KM). DNA was extracted by phenol chloroform method and PCR amplification was performed with Powerplex® Y (Promega) or AmpF1STR Y-Filer (Applied Biosystems). Fragment analysis was done by capillary electrophoresis in an ABI 3130xl. Laboratory results were compared with other data such as, victim age, alleged assailant number, time between the act and collection of biological samples. Significant variables were entered in a logistic regression model using SPSS 17.0 for data analysis. Results and conclusion Descriptive analysis reveals that victim’s age varies between 1 to 90 years old, but almost 20% were under 12 years old. Almost 87% of cases had one perpetrator. Only 10% of the victim’s declared that they had consent sexual intercourse, in the previous 48 hours and 32% take a bath before the exam. Another variable studied was the mean time of 15 hours between the act and biological sample collection. Logistic regression demonstrates that the last two variables are of considerable importance in Y-profile obtention. Concerning acid phosphatase results a male genetic identification was obtained in 12,5 % of the negative cases. In conclusion, Y-STRs study, due to their sensitivity and specificity, should be used in every sexual assault cases, contributing to the final identification of perpetrator’s, and corroborating the victim’s story.
- Diversidade Genética na População de Macau em 15 Loci STRsPublication . Cruz, Carla; Viriato, Luís; Vieira, Claudia; Ribeiro, Teresa; Espinheira, Rosa; Geada, HelenaDecorridos 450 anos de permanência de população portuguesa em território macaense, no dia 20 de Dezembro de 1999, teve lugar a transferência definitiva da soberania de Macau para a República Popular da China. Tendo como objectivo a caracterização genética de uma população originária e residente em Macau e posterior comparação com a população portuguesa, foi efectuado um estudo de um conjunto de 15 loci STRs, dos quais 13 constituem o sistema CODIS e 2 são pentanucleótidos (Penta E e Penta D)A população de Macau mostrou desvios do equilibrio de Hardy-Weinberg nos sistemas D3S1358, TH01, D8S1179, D16S539 e PENTA D, apresentando neste último o desvio mais significativo. Verifica-se que o locus PENTA E é o mais polimórfico e discriminante na população em estudo. A comparação da população macaense com a população portuguesa revelou alelos exclusivos da primeira nos sistemas D18S51 (alelo 24), PENTA E (alelo 24), D5S818 (alelo 7), D7S820 (alelo 9.1), CSF1PO (alelos 14 e 15), vWA (alelo13) e FGA (alelos 13, 16, 25.2 e 26.2). No sistema TPOX a distribuição das frequências alélicas é muito próxima da população portuguesa. Em relação a todos os outros loci, foram detectadas diferenças significativas das frequências dos alelos entre as duas populações. Comparando a população macaense com populações chinesas2,3, verifica-se que estas apresentam semelhanças quanto à distribuição dos alelos nos sistemas estudados, o que sugere proximidade entre as referidas populações.
- 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.
- Human identification with combined anthropologic and genetic tools: two case reports in forensic medicine practicePublication . Amorim, António; Afonso Costa, Heloísa; Espinheira, Rosa; Costa, Rosa; Cunha, Eugénia; Costa Santos, JorgeThe identification of skeletonized corpses or skeletal remains, in forensic medicine practice, as well as being an imperative to human rights respect, has particular relevance and significance in psycho-social terms. If, on one hand, the Universal Declaration of Human Rights advises identification before all body inhumations, on the other hand, returning the identity to an unidentified corpse and subsequent return of the corpse to his family is, itself, the instrument which will allow for the possibility of beginning the family grieving. Forensic anthropology is the first approach towards the identification of unknown skeletonized corpses, which may lead to positive identification of the body or, sometimes, cannot go further than establish some pointers that will lead to further attempt to genetic identification. Here we report two cases of two dead bodies, unidentified, that were presented to the National Institute of Legal Medicine (INML), with instructions, from the prosecutors, to be determined possible cause and circumstances of death and achieve to individual identification. Forensic anthropology, allowed, in both cases, some indications that pointed to alleged missing individuals. Genetic study of skeletonized bodies and family members of the alleged missing individuals has turned possible, in one case, the positive identification. For one of the corpses, most likely due to the weather conditions to which he was exposed for a very considerable period, it was not possible to achieve to positive identification. However, in the latter case, we believe that the use of mitochondrial DNA study may help to settle the case with positive identification of the corps.
- Identificação genética a partir de lâminasPublication . Ribeiro, Teresa; Vieira da Silva, Cláudia; Lucas, Isabel; Dario, Paulo; Geada, Helena; Espinheira, Rosa
- Identificação Genética de Amostras Utilizadas na Determinação da Taxa de AlcoolemiaPublication . Cruz, C.; Vieira da Silva, Cláudia; Ribeiro, Teresa; Lucas, Isabel; Espinheira, RosaA condução sob influência de álcool é responsável por grande parte da sinistralidade rodoviária e a sua fiscalização tem constituído uma das medidas de prevenção dessa sinistralidade. A determinação da Taxa de Alcoolémia no Sangue (TAS) é um dos meios utilizados na fiscalização. No Serviço de Genética e Biologia Forense da Delegação de Lisboa ocorreram solicitações de identificação genética de amostras previamente utilizadas na determinação de TAS.A identificação genética consiste no estudo do perfil de ADN obtido a partir das referidas amostras e na posterior comparação com o perfil de ADN obtido a partir de amostras biológicas de referência, colhidas ao indivíduo sujeito a pesquisa de álcool ou, no caso de falecimento deste, com o perfil genético de familiares directos. Este trabalho descreve os procedimentos realizados na identificação genética das referidas amostras. A comparação dos perfis genéticos obtidos permitiu detectar coincidência/não coincidência ou presença/ausência de uma relação de parentesco entre os referidos perfis e, consequentemente, determinar a identidade da amostra.Este tipo de estudo pode constituir um importante complemento às provas estabelecidas para a detecção do estado de influenciado pelo álcool ou por substâncias estupefacientes ou psicotrópicas.
- Identification by mtDNA of exchanged human body remainsPublication . Cruz, Carla; Ribeiro, Teresa; Vieira - Silva, Cláudia; Lucas, Isabel; Geada, Helena; Espinheira, RosaMtDNA offers some advantages over genomic DNA markers for the identification of human remains. Its sequence is completely determined and the high copy number increases the chance to obtain mtDNA in cases of limited quantity or degraded autosomal DNA. The maternal mode of inheritance without recombination during the meiosis process allows maternal lineage identification by a simple direct comparison of the mtDNA sequence of mother and child or between brothers and sisters. CASE HISTORY: Five Portuguese citizens were killed in African. Three of them were identified and removed to Portugal, where they were buried. Two children were reported as missing. One year later, two skeletons were found in a grave 500 metres from the crime scene. Genetic typing of DNA extracted from skeletal remains was performed in order to establish their identities. One of the mothers of the two missing minors was excluded from the maternity of the skeletal remains. The hypothesis was raised of an identity exchange of the three corpses previously removed to Portugal. These were then exhumed and subjected to genetic analysis to achieve biological identification. Although teeth and bones are reliable sources of DNA, it was difficult to obtain results namely from those retrieved in Africa. As we expected, these required more modifications to standard protocol. The state of the bones samples from this continent was poor, probably due to the humidity, temperature and other African environmental conditions and soil characteristics that accelerate the degradation process. Low amounts, high fragmentation, and contamination of the DNA are the main problems associated with this kind of sample. In some cases, increasing the amount of DNA helped to overcome the first problem, but in some others lead to negative results, which can be explained by an increase of Taq polymerase inhibitors in the mix reaction. Regarding the degraded DNA, the application of different primers to the HVI and HVII regions allowed the amplification of two shorter overlapping fragments for each region and the reconstruction of HVI and HVII sequences. Several dilutions of DNA extract were tested to decrease the hypothetical contaminants that would act as Taq polymerase inhibitors. The coincidence of each of the five body sequences with one of the alleged mothers suggests a maternal relationship. A fraternal relationship was detected between bodies 2 and 5. These share the same mtDNA sequence with mother 3. The results supported the hypothesis of exchanged human body remains. Autosomal STR loci analysis was performed and confirmed the identity of the human remains. MtDNA analysis was a useful tool to solve this case. Although it cannot be used to definitely identify the corpses, it provided evidence of a maternal relationship and, consequently, the exchange of human body remains.
- 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