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Brazilian forensic casework analysis through MPS applications: Statistical weight-of-evidence and biological nature of criminal samples as an influence factor in quality metrics.
Forensic Sci Int. 2019 Oct; 303:109938.FS

Abstract

Real forensic casework biological evidence can be found in a myriad of different conditions and presenting very distinct features, including key elements such as degradation levels, the nature of biological evidence, mixture presence, and surface or substrate deposition, among others. Technical protocols employed by forensic DNA analysts must consider such characteristics in order to improve the chances of successfully genotyping these materials. MPS has been used as a very useful tool for forensic sample processing and genetic profile generation. However, it is not completely clear how different features encountered with real forensic samples impact sequencing quality and, consequently, profile accuracy and reliability. In this context, the present study analyzes a set of 47 real forensic casework samples, obtained from semen, saliva, blood and epithelial evidence, as well as reference oral swabs, aiming to evaluate the impact of a sample's biological nature in profiling success. All DNA extracts from samples were standardized according to sample conditions, as assessed by traditional forensic profiling methods (real-time PCR quantitation and capillary electrophoresis-coupled STR fragment analysis). Samples were separated into groups according to their biological nature, and the resultant sequencing quality was evaluated through a series of well-established statistical tests, applied specifically to six different MPS quality metrics. The results showed that certain groups of samples, especially epithelial and (to a lesser extent) saliva samples, exhibited significantly lower quality in terms of some of the evaluated metrics. A number of reasons for such unexpected behavior are discussed. In addition, a series of calculations was performed to assess the weight of genetic evidence in Brazilian samples, and reflexes in data analysis and national allele frequency database construction are discussed. Overall, the results indicate that a unified national allele frequency database can be used nationwide. Besides this, MPS genetic profiles obtained from samples with particular biological origins may benefit from meticulous manual review, and visual inspection could be important as an additional step to avoid genotyping errors or misinterpretation, leading to more trustworthy and reliable results in real criminal forensic casework analysis.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Avila E
Setor Técnico-Científico, Superintendência Regional do Rio Grande do Sul, Polícia Federal, Porto Alegre, Brazil; Escola de Ciências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Instituto Nacional de Ciência e Tecnologia INCT Ciências Forenses, Porto Alegre, Brazil. Electronic address: e.avila@edu.pucrs.br.
Cavalheiro CP
Escola de Ciências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
Felkl AB
Escola de Ciências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
Graebin P
Escola de Ciências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
Kahmann A
Instituto de Matemática, Estatística e Física, Universidade Federal de Rio Grande, Rio Grande, Brazil.
Alho CS
Escola de Ciências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil; Instituto Nacional de Ciência e Tecnologia INCT Ciências Forenses, Porto Alegre, Brazil.

MeSH

Blood Chemical AnalysisBrazilDNA FingerprintingDatabases, GeneticElectrophoresis, CapillaryEpithelial CellsGene FrequencyGenetics, PopulationHigh-Throughput Nucleotide SequencingHumansMicrosatellite RepeatsPolymorphism, Single NucleotideReal-Time Polymerase Chain ReactionSalivaSemenSequence Analysis, DNA

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31542402

Citation

Avila, E, et al. "Brazilian Forensic Casework Analysis Through MPS Applications: Statistical Weight-of-evidence and Biological Nature of Criminal Samples as an Influence Factor in Quality Metrics." Forensic Science International, vol. 303, 2019, p. 109938.
Avila E, Cavalheiro CP, Felkl AB, et al. Brazilian forensic casework analysis through MPS applications: Statistical weight-of-evidence and biological nature of criminal samples as an influence factor in quality metrics. Forensic Sci Int. 2019;303:109938.
Avila, E., Cavalheiro, C. P., Felkl, A. B., Graebin, P., Kahmann, A., & Alho, C. S. (2019). Brazilian forensic casework analysis through MPS applications: Statistical weight-of-evidence and biological nature of criminal samples as an influence factor in quality metrics. Forensic Science International, 303, 109938. https://doi.org/10.1016/j.forsciint.2019.109938
Avila E, et al. Brazilian Forensic Casework Analysis Through MPS Applications: Statistical Weight-of-evidence and Biological Nature of Criminal Samples as an Influence Factor in Quality Metrics. Forensic Sci Int. 2019;303:109938. PubMed PMID: 31542402.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Brazilian forensic casework analysis through MPS applications: Statistical weight-of-evidence and biological nature of criminal samples as an influence factor in quality metrics. AU - Avila,E, AU - Cavalheiro,C P, AU - Felkl,A B, AU - Graebin,P, AU - Kahmann,A, AU - Alho,C S, Y1 - 2019/09/12/ PY - 2019/07/23/received PY - 2019/08/22/accepted PY - 2019/9/23/pubmed PY - 2019/12/20/medline PY - 2019/9/23/entrez KW - Brazilian Federal Police KW - Forensic KW - HID ion Ampliseq identity panel KW - Massive Parallel Sequencing KW - Nature of biological evidence KW - Quality metrics KW - SNP SP - 109938 EP - 109938 JF - Forensic science international JO - Forensic Sci Int VL - 303 N2 - Real forensic casework biological evidence can be found in a myriad of different conditions and presenting very distinct features, including key elements such as degradation levels, the nature of biological evidence, mixture presence, and surface or substrate deposition, among others. Technical protocols employed by forensic DNA analysts must consider such characteristics in order to improve the chances of successfully genotyping these materials. MPS has been used as a very useful tool for forensic sample processing and genetic profile generation. However, it is not completely clear how different features encountered with real forensic samples impact sequencing quality and, consequently, profile accuracy and reliability. In this context, the present study analyzes a set of 47 real forensic casework samples, obtained from semen, saliva, blood and epithelial evidence, as well as reference oral swabs, aiming to evaluate the impact of a sample's biological nature in profiling success. All DNA extracts from samples were standardized according to sample conditions, as assessed by traditional forensic profiling methods (real-time PCR quantitation and capillary electrophoresis-coupled STR fragment analysis). Samples were separated into groups according to their biological nature, and the resultant sequencing quality was evaluated through a series of well-established statistical tests, applied specifically to six different MPS quality metrics. The results showed that certain groups of samples, especially epithelial and (to a lesser extent) saliva samples, exhibited significantly lower quality in terms of some of the evaluated metrics. A number of reasons for such unexpected behavior are discussed. In addition, a series of calculations was performed to assess the weight of genetic evidence in Brazilian samples, and reflexes in data analysis and national allele frequency database construction are discussed. Overall, the results indicate that a unified national allele frequency database can be used nationwide. Besides this, MPS genetic profiles obtained from samples with particular biological origins may benefit from meticulous manual review, and visual inspection could be important as an additional step to avoid genotyping errors or misinterpretation, leading to more trustworthy and reliable results in real criminal forensic casework analysis. SN - 1872-6283 UR - https://www.unboundmedicine.com/medline/citation/31542402/Brazilian_forensic_casework_analysis_through_MPS_applications:_Statistical_weight_of_evidence_and_biological_nature_of_criminal_samples_as_an_influence_factor_in_quality_metrics_ DB - PRIME DP - Unbound Medicine ER -