Browsing by Issue Date, starting with "2003-09"
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- A informação como recurso estratégico na sociedade do conhecimentoPublication . Mata, Carlos; Gonçalves, SidalinaA globalização e a crescente competitividade das organizações produziram profundas transformações na concepção dos sistemas de informação contabilísticos. Na procura de adaptação aos novos desafios da Sociedade do Conhecimento surge a necessidade de conhecer todos os factores para a tomada de decisão. Afigura-se uma nova classe de informação direccionada para a análise competitiva, avaliando a estratégia delineada pela organização e a sua cadeia de valor. A Contabilidade enquanto instrumento de gestão deve permitir o planeamento e controlo das actividades e dos recursos bem como a medição da performance face aos novos paradigmas organizacionais para vencer no mundo actual.
- 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.
- 16 Y-Specific STR Analysis in Human Remains IdentificationPublication . Vieira-Silva, Cláudia; Cruz, C.; Ribeiro, Teresa; Lucas, Isabel; Geada, H.; Espinheira, R.Forensic investigation often requires the use of degraded biological material, especially for determining the identity of human remains. Y-STRs, offer new perspectives for identification and kinship analysis especially on forensic deficiency cases 1 in complement of autosomal STRs. The non-recombining portion of the Y-chromosome is of value providing additional data in paternal lineage identification. The aim was the study of 16 Y-STR loci to perform human remains identification - the minimal Y-STR haplotype - DYS19, DYS390, DYS391, DYS392, DYS393, DYS19, DYS389I/II, DYS385 – and – GATA A .1(DYS460), GATA A 7.2 (DYS461), GATA C4, GATA H4, DYS437, DYS438, DYS439 loci, that are part of the Y-chromosome quality control Group of the Spanish and Portuguese Group (GEPY) of the ISFG. Y-STR typing in degraded biological material has major technical challenges since each sample has unique characteristics. The best results were obtained in autopsy bloodstains may be due to the fact that the autolysis mechanisms are still incipient. Otherwise blood kept at 4º C for more than a year didn’t provide the same good results. Liquid blood samples from deceased individuals may contain porfirinic compounds from hemoglobin, powerful PCR inhibitors difficult to eliminate9. In bone and teeth samples the source of inhibitors may be a high amount of DNA from other micro-organisms such as bacteria and fungi which invade bone9 and probably this kind of contaminants can explain some of the results obtained in bones and teeth samples submitted to prolonged humidity, temperature environmental conditions and also adverse soil characteristics. The problem with the studied samples seems not to be DNA quantity but the out-of-control presence of inhibitors that interfere not only with the extraction but also with the amplification process because most of the results were obtained with a dilution of DNA extraction and adding more Taq, sometimes 2 or 3 fold. With these samples, it seems that the success or failure depends on each sample itself and it should be treated individually. The number of distinct factors connected to each sample is difficult to calculate, so it is necessary to make a few attempts in order to have as many results as possible.
- vWA STR Locus - Structure and variabilityPublication . Cruz, Carla; Vieira da Silva, Cláudia; Lucas, Isabel; Ribeiro, Teresa; Espinheira, Rosa; Geada, HelenaThe biological individualization of samples is studied through DNA STR loci analysis and is the principal goal of Forensic Genetics. STR loci study was initiated in the 90s on the majority of Forensic Laboratories. vWA is one of the most studied STR loci all over the world. It is included in any STR set proposed by Forensic Groups as the 13 core loci of the CODIS System used in routine cases by most Forensic Genetic Laboratories. When performing paternity investigation and identification cases with STR loci, once in a while we came through rare or new alleles. Sequencing is essential to confirm the structure of these alleles. Also in mutation cases, especially in primer binding mutation cases, allele sequence should be performed. The high primer binding mutation observed in this locus and the interest in structure analysis of rare alleles observed in certain population groups were the main reasons for performing vWA sequence. More than one hundred vWA samples have been sequenced with DNA Sequencing Kit Big Dye Terminator Cycle Sequencing with forward and reverse primers (Kimpton et al, 1992 GenBank M25858). Sequencing was performed in an ABIPRISM 377 DNA Sequencer and analyzed by Sequencing Analysis. In this study we will present the structural analysis of vWA alleles from allele 11 to allele 22 studied in two main populations – a Portuguese population and an African population mainly from Cabo Verde Islands and Angola
- Portuguese Population Study with 16 Y-STR LociPublication . Geada, Helena; Baptista, Joana; Felgueiras, Miguel; Vieira Da Silva, Cláudia; Cruz, Carla; Lucas, Isabel; Ribeiro, Teresa; Espinheira, RosaAlthough autosomal STRs are commonly used for forensic investigations, Y-chromosome STRs provide very useful information in paternity investigation cases without alleged father and investigation cases where paternal lineage identification can be assessed. The aim of this study is to present an extended 16 Y-STR Portuguese Population Database of 214 Southern Portugal individual samples for forensic purpose, including the 8 Y-STR minimal haplotype – DYS19, DYS389 I/II, DYS390, DYS391, DYS392, DYS393, DYS385 (Gusmão et al, 2001, D Syndercomb-Court, personal communication) and Y-STR loci included in the Y-Chromosome GEP-ISFG collaborative exercise – DYS437, DYS438, DYS439, DYS460, DYS461, GATA A10, GATA C4, GATA H4.When performing a 16 Y-STR study the genetic diversity was successfully increased. With the 8 Y-STR minimal haplotype, haplotype clusters can be detected involving several non-related individuals, whereas, with a 16 Y-STR haplotype, haplotype clusters involve only 2 or 3 non-related individuals. The 16 Y-chromosome STR haplotype seem to be extremely important to solve complex forensic cases and in population, studies to obtain unique paternal profiles and to determine specific population characteristics