Avaliação de DNA de toque depositado em tela de aparelho celular para finalidade forense
Data
2024-06-25
Autores
Kisberi, Juliany Barreto 
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Os avanços na área forense permitiram o desenvolvimento de um novo método de análise, que consiste na obtenção de perfis genéticos de STR por meio do DNA depositado através do toque. A partir dos estudos do DNA de toque, foi identificada a existência de diversas variáveis associadas à sua deposição. Historicamente, associou-se o DNA de toque apenas à descamação das mãos, ignorando outras fontes como o sebo facial. Desse modo, esta pesquisa visa avaliar fatores (sebo, sexo e faixa etária) que podem influenciar a deposição de DNA de toque considerando a superfície de vidro das telas de aparelhos celulares. Para esse fim, foram selecionados quinze homens e quinze mulheres, os quais foram divididos em três faixas etárias (18-29 anos, 30-49 anos e ≥50 anos), excluindo-se aqueles com doenças dermatológicas que afetam as mãos ou a face, descamação frequente e fumantes. Os voluntários forneceram DNA de toque em dois dias de experimento, coletado por meio de swab duplo. No primeiro dia, foi testado o toque prévio a face (região sebácea) e, no segundo, a deposição do DNA endógeno das mãos (região não sebácea). Após a extração do DNA, foi realizada PCR (kit PowerPlex® ESI17 System, que contém 16 STR autossômicos e o marcador de sexo - amelogenina) e eletroforese capilar. Os perfis das amostras-referência (swab oral) foram comparados com os das amostras de touch DNA e foi calculada a porcentagem de alelos concordantes para cada indivíduo e quantidade de marcadores completos. Os resultados mostraram que o contato com região sebácea antes da deposição de DNA de toque em telas de aparelhos celulares contribui para a obtenção de percentuais de alelos concordantes maiores do que os obtidos por meio do DNA produzido pelas mãos (p=0,0021), assim como, permite a obtenção de perfis genéticos com melhor qualidade – parciais e completos – (p=0,047) e maior quantidade de perfis úteis para a identificação humana (p=0,0022), de acordo com os critérios estabelecidos pela Rede Integrada Brasileira de Perfis Genéticos (RIBPG). Ademais, destaca-se a ausência de significância estatística para a influência do sexo e faixa etária sobre os percentuais de alelos coincidentes obtidos ao considerar o sebo como origem do DNA de toque, bem como, quando foi considerado o DNA endógeno das mãos como fonte do material genético. Além disso, foi avaliada a influência dos fatores sexo e faixa etária sobre o tipo de perfil gerado (nulo, parcial e completo) e a utilidade na identificação humana, não havendo significância estatística para ambas as origens de DNA analisadas. Assim, os resultados obtidos mostraram a possibilidade de recuperar perfis genéticos a partir do DNA de toque depositado em telas de aparelhos celulares e a confirmação de que o contato com regiões sebáceas potencializa a qualidade dos perfis genéticos de STR autossômicos. Esse resultado é interessante para a área forense, indicando que em casos de impressões digitais pouco úteis para análises datiloscópicas, a coleta do DNA de toque consiste em alternativa viável, podendo gerar muitos perfis parciais e alguns perfis completos.
Advances in forensics enabled the development of a new method of analysis, which consists of obtaining STR genetic profiles using DNA deposited by touch. Studies of touch DNA have identified several variables associated with its deposition. Historically, touch DNA has only been associated with hand shedding, ignoring other sources such as facial sebum. Therefore, this study aims to evaluate factors (sebum, sex and age group) that may influence the deposition of touch DNA on the glass surface of cell phone screens. To this end, fifteen men and fifteen women were selected and separated into three age groups (18-29 years, 30-49 years and ≥50 years), excluding those with dermatological diseases affecting the hands or face, frequent shedding and smokers. The volunteers donated touch DNA on two days of the experiment, collected using the double swab. On the first day, prior touch to the face (sebaceous region) was tested, and on the second, the deposition of endogenous DNA from the hands (non-sebaceous region). After DNA extraction, PCR (PowerPlex® ESI17 System kit, which contains 16 autosomal STRs and the sex marker amelogenin) and capillary electrophoresis were performed. The profiles of the reference samples (oral swab) were compared with those of the touch DNA samples and the percentage of concordant alleles for each individual and the number of complete markers were calculated. The results showed that contact with the sebaceous region prior to the deposition of touch DNA on cell phone screens contributes to obtaining higher percentages of matching alleles than those obtained using DNA produced by the hands (p=0.0021), as well as enabling better quality genetic profiles - partial and complete - to be obtained (p=0.047) and a greater number of profiles useful for human identification (p=0.0022), in accordance with the criteria established by the Brazilian Integrated Network of Genetic Profiles (RIBPG). Furthermore, there was no statistical significance for the influence of sex and age group on the percentage of coincident alleles obtained when considering sebum as the source of the touch DNA, as well as when considering endogenous DNA from the hands as the source of the genetic material. In addition, the influence of sex and age on the type of profile generated (null, partial and complete) and its usefulness in human identification was evaluated, with no statistical significance for both DNA sources analyzed. Thus, the results obtained show that it is possible to recover genetic profiles from touch DNA deposited on cell phone screens and confirm that contact with sebaceous regions enhances the quality of autosomal STR genetic profiles. This result is interesting for the forensic area, indicating that in cases of fingerprints that are not very useful for datiloscopic analysis, the collection of touch DNA is a viable alternative that can generate many partial profiles and some complete profiles.
Advances in forensics enabled the development of a new method of analysis, which consists of obtaining STR genetic profiles using DNA deposited by touch. Studies of touch DNA have identified several variables associated with its deposition. Historically, touch DNA has only been associated with hand shedding, ignoring other sources such as facial sebum. Therefore, this study aims to evaluate factors (sebum, sex and age group) that may influence the deposition of touch DNA on the glass surface of cell phone screens. To this end, fifteen men and fifteen women were selected and separated into three age groups (18-29 years, 30-49 years and ≥50 years), excluding those with dermatological diseases affecting the hands or face, frequent shedding and smokers. The volunteers donated touch DNA on two days of the experiment, collected using the double swab. On the first day, prior touch to the face (sebaceous region) was tested, and on the second, the deposition of endogenous DNA from the hands (non-sebaceous region). After DNA extraction, PCR (PowerPlex® ESI17 System kit, which contains 16 autosomal STRs and the sex marker amelogenin) and capillary electrophoresis were performed. The profiles of the reference samples (oral swab) were compared with those of the touch DNA samples and the percentage of concordant alleles for each individual and the number of complete markers were calculated. The results showed that contact with the sebaceous region prior to the deposition of touch DNA on cell phone screens contributes to obtaining higher percentages of matching alleles than those obtained using DNA produced by the hands (p=0.0021), as well as enabling better quality genetic profiles - partial and complete - to be obtained (p=0.047) and a greater number of profiles useful for human identification (p=0.0022), in accordance with the criteria established by the Brazilian Integrated Network of Genetic Profiles (RIBPG). Furthermore, there was no statistical significance for the influence of sex and age group on the percentage of coincident alleles obtained when considering sebum as the source of the touch DNA, as well as when considering endogenous DNA from the hands as the source of the genetic material. In addition, the influence of sex and age on the type of profile generated (null, partial and complete) and its usefulness in human identification was evaluated, with no statistical significance for both DNA sources analyzed. Thus, the results obtained show that it is possible to recover genetic profiles from touch DNA deposited on cell phone screens and confirm that contact with sebaceous regions enhances the quality of autosomal STR genetic profiles. This result is interesting for the forensic area, indicating that in cases of fingerprints that are not very useful for datiloscopic analysis, the collection of touch DNA is a viable alternative that can generate many partial profiles and some complete profiles.
Descrição
Citação
KISBERI, Juliany Barreto. Avaliação de DNA de toque depositado em tela de aparelho celular para finalidade forense. 2024. 96 f. Trabalho de Conclusão de Curso (Graduação em Biomedicina) - Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2024.