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Publication
Genética Forense: Do Perfil Genético ao Relatório Pericial
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Abstract(s)
DNA typing, since it was introduced, in the mid-1980s, has revolutionized forensic science and the ability to link an individual to a judicial proceeding under civil or criminal law. Forensic genetic analysis involves procedures from sample collection and storage, DNA extraction and quantification (whenever it is deemed necessary), amplification of the genetic markers, and subsequent analysis of these amplified products A forensic genetic profile, represented in an electropherogram, corresponds to a graphic representation that relates time/size and fluorescence intensity at various wavelengths of light of these amplified products. Statistical analysis of genetic profiles related to the same process is preponderant for evidence evaluation and report drafting.
In paternity investigations, the simplest and commonest example is whether a man is the biological father of a child, and it involves, DNA tests of the mother, child, and alleged father together. In recent years, there has been an increase in testing how a set of persons are related. In these cases, the strength of the evidence from DNA data may often be much weaker than in trio paternity cases and it doesn´t provide strong evidence for or against paternity. The greatest challenges today, are complex calculations, in which the autosomal STRS genetic profiles are not enough, and more information is required, including with X -STRs (X-chromosome markers) or Y -STRs (Y-chromosome markers) or even more genetic markers.
Regarding trace samples, collected in criminal cases, or collected from suspects or victims and crime scenes represent greater challenges. Recent advances in DNA typing technologies have led to analysis of increasingly complex DNA mixtures of two, three, or even more contributors, commonplace in casework, but with challenging interpretation, and in many cases the forensic scientist questions if these complex STR profiles, with high and/or low template component mixed samples should be analyzed. Guidelines for mixture interpretation, have been published by different entities, in order to, obtain some kind of consensus in the evaluation of these genetic profiles.
Tree kinship cases and tree criminal cases, with STR results and reported conclusions, will be presented to illustrate different challenging situations in the evaluation of genetic profiling evidence.
In the near future, biggest challenges will be posed concerning genetic information from new MPS (Massive parallel sequencing equipment) and the developing of the new integrative statistical framework with prototype software for combined appearance, age, and ancestry prediction, allowing constructing of composite sketches from DNA and then assessing how this information can be included in the expert reports.
Description
Palestra apresentada no VIII Congresso Internacional de Ciências Forenses e Comportamento Criminal, organizada por Instituto Superior de Saúde Egas Moniz - Cooperativa de Ensino Superior, Almada, Portugal, 1 de Julho de 2022
Keywords
Likelihood Ratio Valorização Prova Perfil genético Mistura de perfis Genética Forense