DNA phenotyping: current application in forensic science

Leonardo Arduino Marano,1 Cintia Fridman2 1Laboratório de Genética Molecular Forense, Polícia Científica do Estado do Paraná, Curitiba, PR, Brazil; 2Departamento de Medicina Legal, Ética Médica e Medicina Social e do Trabalho, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, SP, Brazil Abstract: DNA analysis for forensic investigations is based on the idea that each individual is genetically unique, except in cases of monozygotic twins. DNA obtained from biological samples is able to individualize this material by direct comparison of short tandem repeats genetic profile, obtained from biological samples of unknown origin to a reference sample profile. One of the major limitations of this approach is the need for a reference sample for comparison. Numerous studies seeking to understand the relationship between certain polymorphisms and certain phenotypic characteristics are increasing and have generated promising results in aiding forensic sciences. The process of inferring externally visible characteristics (EVCs) with forensic purpose – eg, the color of skin, iris and hair, height, facial features, and male baldness pattern – from biological samples is known as forensic DNA phenotyping (FDP). Therefore, FDP provides more details about the subject to which a given biological sample belongs, without the need for a reference sample for comparative analysis. Some ethical and legal aspects should be taken into account so that this new technology does not promote segregation or ethnic persecution of certain population groups. Despite this, several real cases have benefited from these methods to orientate investigations to identify both suspects and victims. Keywords: forensic DNA phenotyping, DNA, externally visible characteristics, forensic genetics