Jorge Costa Santos

Analysis of 17 STR data on 5362 southern Portuguese individuals—an update on reference database

The main objective of this work consisted of the updating of allele frequencies and other relevant forensic parameters for the 17 autosomal STR loci provided by the combination of the two types of kits used routinely in our laboratory casework: AmpF/STR Identifiler(®) and the Powerplex(®) 16 Systems. This aim was of significant importance, given that the last study on these kits within the southern Portuguese population dates back to 2006, and, as a consequence, it was necessary to correct the deviation caused by population evolution over the last ten years so that they might be better applied to our forensic casework. For this reason genetic data from 5362 unrelated Caucasian Portuguese individuals from the south of Portugal who were involved in paternity testing casework from 2005 to 2014 was used. Of all the markers, TPOX proved to be the least polymorphic, and Penta E the most. Secondly, this up-to-date southern Portuguese population was compared not only with the northern and central Portuguese populations, but also with that of southern Portugal in 2006, along with populations from Spain, Italy, Greece, Romania, Morocco, Angola and Korea in order to infer information about the relatedness of these respective populations, and the variation of the southern Portuguese population over time.

Genetic portrait of south Portugal population with InDel markers

In human genetic identification the selection of highly polymorphic markers it is very important in order to obtain a high discrimination power even when the number of loci is limited. STR typing continues to be the most robust and reliable method for samples with small amounts of purified and non-degraded DNA. Nonetheless, STR typing has some limitations, such as large amplicon sizes between 150 and 450 base pairs, which can contribute for poor results in challenging forensic samples [1], and also some technical issues like the presence of artefacts, like stutter

Enterococci from artisanal dairy products show high levels of adaptability

Enterococci are ubiquitous organisms able to promote both health (fermented food/probiotics) and illness (human/animal infections). Disturbingly, several enterococcal species commonly found in artisanal cheeses, such as Enterococcus faecalis and E. faecium, are being increasingly established as causes of infection, posing a problem for food safety. In this study enterococci from ewes milk and cheese were compared to clinical and reference strains by growth in media simulating environmental colonization and infection sites: 2YT, BHI, skim milk, urine and rabbit serum at different pHs, NaCl concentrations and temperatures. Growth curves were obtained with Microbiology Workstation Bioscreen C and used to calculate relative indexes--RIs--(based on absorbance, lag phase and specific growth rate) for each strain and environmental condition. Similar or higher RIs were obtained for food strains growing in infection-related environments when compared to clinical ones, revealing their ability to adapt and grow in these conditions. A dendrogram built using Pearsons correlation coefficient and a PCA analysis clustered the strains regardless of their origin or species allocation, suggesting a strain-specific mode of growth and a high environmental adaptability of enterococcal strains. These evidences turn essential the evaluation of strains to be used as starters or probiotics.

How to do identify single cases according to the quality assurance from IOFOS. The positive identification of an unidentified body by dental parameters: A case of homicide

UNLABELLED The positive identification of skeletal by individual dental parameters is one of the objectives of the criminal investigation. The intervention of Forensic Dentistry in some circumstances may represent the only way to obtaining a positive identification of an unidentified bodies. The teeth constitute a scientific method in forensic identification, principally due to the great resistance to the agents who provoke the destruction of the soft tissues in the corpses (putrefaction, traumatic, physical and chemical agents) and to the high morphological variability of the human teeth. The human identification in Forensic Dentistry is made by two ways: comparative and reconstructive. The identification allows to determine several parameters of forensic interest: specimen, population affinity, sex, age, stature and individualizations factors. The Forensic Dentistry is one of the most important fields in individual identification, because teeth have less variability in the chronology of events in terms of the reconstructive way. On the other side, in terms of the comparative way, this area is also important, because of the individualizations factors: positive identification in individual cases and in mass disasters. In this forensic case report, a homicide case, the objective of the medico-legal investigation was a positive identification of the unidentified corpse found one year after the crime, July 2010. The Portuguese Criminal Police of Lisbon, Homicide Group, requested to South Branch of the Portuguese National Institute of Forensic Medicine, a forensic examination by a Forensic Odontologist for dental positive identification. The objectives were: 1) post mortem reconstruction of the dental status of the victim; 2) obtain the ante mortem information of the presumable victims; 3) comparison of the post mortem information with the ante mortem information, for a positive identification of the presumable homicide victim. MATERIALS AND METHODS in this field of dental investigation, the guidelines of the International Organization of Forensic Odontology were used for reconstruction of the post mortem dental profile, to register ante mortem information of the presumable victims and to compared for individualized dental factors, by using Interpol DVI Forms for Individual Case, post mortem and ante mortem forms F1 and F2. RESULTS the unidentified victim of homicide was positive identified where it was established the identity by more than 12 individual dental characteristics. CONCLUSION the Forensic Dentistry is a very important and simple field for individual identification of unidentified corpses for application of the criminal law.

Population data of the GlobalFiler® Express loci in South Portuguese population

Allele frequencies and other relevant forensic parameters for 21 loci studied with GlobalFiler(®) Express amplification kit (Life Technologies) were calculated in a population of individuals residing in the south of Portugal. Blood stain samples were obtained from a total of 502 unrelated individuals involved in paternity testing casework and directly PCR amplified with GlobalFiler(®) Express following manufacturers instructions. This kit comprises all the loci included in the extended European Standard Set (ESS) and in the Combined DNA Index System (CODIS), besides the very polymorphic D2S441, D19S433, and SE33. In our laboratory this is used as a screening tool to solve complex cases, as fatherless paternity tests or to help in paternity investigations where there is the need to study additional genetic markers. These studies are necessary to calculate statistical forensic parameters, such as power of discrimination or as power of exclusion. Statistical parameters including heterozigosity, homozigosity and combined power of exclusion were estimated.

Genetic portrait of Lisboa immigrant population from Angola with mitochondrial DNA

Portugal has been considered a country of emigrants, nevertheless in the past decades the number of immigrants has grown throughout all the country. This migratory flux has contributed to a raise of heterogeneity at multiple levels. According to statistical data, at the end of 2012 the total number of Angolan immigrants in Portugal equalled about 20,000 individuals. A territorial predominance has been found for the metropolitan region of Lisboa. Angola is a country located in the Atlantic coast of Africa. The presence of Bantu people and the colonisation by Portuguese people on Angolan territory are considered to be the major modulators of the genetic patterns in Angola. Mitochondrial DNA is known for its features that enable an approach to the study of human origin and evolution, as well to the different migration pathways of populations. This genetic marker can also contribute to ascertaining the identity of individuals in forensic cases. The main aim of this study was to determine the genetic structure of the Angolan immigrant population living in Lisboa. Therefore, a total of 173 individuals, inhabitants in Lisboa, nonrelated and with Angolan ancestry were studied. Total control region of mitochondrial DNA was amplified from position 16,024 to position 576 using two pairs of primers - L15997/H016 and L16555/H639. The majority of the identified haplotypes belong to mtDNA lineages known to be specific of the sub-Saharan region. Our results show that this immigrant population inhabitant in Lisboa presents a genetic profile that is characteristic of African populations. This study also demonstrates the genetic diversity that this immigrant population introduces in Lisboa. This does not contradict the historical data concerning colonization of Angola, since this was made mainly by male European individuals, who did not contribute with their maternal information of mtDNA. Lisboa immigrant population from Angola can be accessed via EMPOP dataset with accession number EMPOP662.

Genetic portrait of Lisboa immigrant population from Cabo Verde with mitochondrial DNA analysis

Cabo Verde is a group of 10 volcanic islands and several uninhabited islets located on the west African coast and belongs to a group of four archipelagos located in the Atlantic Ocean (Acores, Madeira, Islas Canarias and Cabo Verde), namedMacaronesia. The Portuguese colonization began soon after the discovery of the archipelago in 1460 with Santiago and Fogo being the first islands to be populated. The first settlers arrived in 1462 on the island of Santiago and were an assortment of Portuguese nobles, Jews, exiles and convicts (Willie 2001). Cabo Verde remained a colony of the Portuguese Colonial Empire until 1975 when the independence was proclaimed and the country became formally an independent nation. In the 19th century, drought and famine promoted strong migration movements between the isles of the archipelago and other regions. Migration is present in the historic and social reality of Cabo Verde archipelago since the establishment of its society. According to the 2008 survey released by the Cabo Verde National Institute of Statistics, the country had about 500,000 inhabitants. Conjointly with Europe, the immigrant population of Portugal and particularly Lisboa, is clearly increasing. This migration contributes not only increase in the number of inhabitants, but also to increase the social, cultural,

Evidence Collection of a Tooth Mark in a Crime Scene: Importance of the Dental Materials in Forensic Dentistry

Abstract The forensic dentistry is commonly required to identify tooth marks from a crime scene. The methodology is unique according to the guidelines of American Board of Forensic Sciences (ABFO) and International Organization of Forensic OdontoStomatology (IOFOS), using proper techniques for collection and preservation of evidence for the last stage comparison with suspects. This forensic case applies those guidelines to collect two set of tooth marks present on two pieces of cheese found at a crime scene. The dental impression and model materials are very important to preserving the physical evidence present on inanimate materials such as cheese to later on compare with the teeth of a suspected and make a conclusion.

Study of InDel genetic markers with forensic and ancestry informative interest in PALOP's immigrant populations in Lisboa.

The migratory phenomenon in Portugal has become one of the main factors for the genetic variability. In the last few years, a new class of autosomal insertion/deletion markers—InDel—has attracted interest in forensic genetics. Since there is no data for InDel markers of Portuguese-speaking African countries (PALOP) immigrants living in Lisboa, our aim is the characterization of those groups of individuals by typing them with at least 30 InDel markers and to compare different groups of individuals/populations. We studied 454 bloodstain samples belonging to immigrant individuals from Angola, Guinea-Bissau, and Mozambique. DNA extraction was performed with the Chelex® 100 method. After extraction, all samples were typed with the Investigator® DIPplex method. Through the obtained results, allelic frequencies show that all markers are at Hardy-Weinberg equilibrium, and we can confirm that those populations show significant genetic distances between themselves, between them, and the host Lisboa population. Because of this, they introduce genetic variability in Lisboa population.

Sequencing CYP2D6 for the detection of poor-metabolizers in post-mortem blood samples with tramadol

Tramadol concentrations and analgesic effect are dependent on the CYP2D6 enzymatic activity. It is well known that some genetic polymorphisms are responsible for the variability in the expression of this enzyme and in the individual drug response. The detection of allelic variants described as non-functional can be useful to explain some circumstances of death in the study of post-mortem cases with tramadol. A Sanger sequencing methodology was developed for the detection of genetic variants that cause absent or reduced CYP2D6 activity, such as *3, *4, *6, *8, *10 and *12 alleles. This methodology, as well as the GC/MS method for the detection and quantification of tramadol and its main metabolites in blood samples was fully validated in accordance with international guidelines. Both methodologies were successfully applied to 100 post-mortem blood samples and the relation between toxicological and genetic results evaluated. Tramadol metabolism, expressed as its metabolites concentration ratio (N-desmethyltramadol/O-desmethyltramadol), has been shown to be correlated with the poor-metabolizer phenotype based on genetic characterization. It was also demonstrated the importance of enzyme inhibitors identification in toxicological analysis. According to our knowledge, this is the first study where a CYP2D6 sequencing methodology is validated and applied to post-mortem samples, in Portugal. The developed methodology allows the data collection of post-mortem cases, which is of primordial importance to enhance the application of these genetic tools to forensic toxicology and pathology.