Publications by authors named "Heitor Simoes Dutra Correa"

5 Publications

  • Page 1 of 1

Human identification through DNA analysis of restored postmortem teeth.

Forensic Sci Int Genet 2020 Jul 20;47:102302. Epub 2020 Apr 20.

University of Brescia - Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Forensic Medicine Unit, Brescia, Italy.

The identification of human remains using DNA analysis can be extremely challenging and its success is certainly influenced by the time elapsed since death. In that context, intact teeth have been shown to be highly successful in DNA analysis. However, restored teeth are usually available and, surprisingly, these specimens have been poorly studied. In fact, there are no reports regarding forensic DNA analysis of those types of samples in real cases. Therefore, the aim of this study was to perform DNA typing on healthy and restored teeth from exhumed human remains, which had been buried for 46 years. A powder-free DNA extraction protocol specifically designed for teeth was followed and human DNA quantitation and degradation assessment was performed using an in-house qPCR assay. Samples were amplified with commercial human identification kits for autosomal and Y chromosome markers. The obtained DNA profiles were compared to those of a previously processed femur sample as well as a buccal swab from a putative son. One healthy and one restored tooth yielded complete, concordant and compatible DNA profiles with previously typed samples from the femur and the putative son. Biostatistical calculations supported the paternity relationship with a likelihood ratio greater than 11 million. The present study highlights the use of restored teeth in a real exhumation case and the powder-free approach specifically designed for the extraction of DNA from teeth is discussed.
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http://dx.doi.org/10.1016/j.fsigen.2020.102302DOI Listing
July 2020

DNA quantitation and degradation assessment: a quantitative PCR protocol designed for small forensic genetics laboratories.

Electrophoresis 2020 05 10;41(9):714-719. Epub 2020 Mar 10.

Forensic Medicine Unit, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy.

For over 10 years, quantitative PCR (qPCR) for DNA quantitation has been reported in forensics. However, assays have not been described for small qPCR platforms. Thus, technological advancement is not always implemented in small forensic genetics laboratories. A duplex qPCR assay is reported, using a StepOne instrument and targeting a short and a long human DNA region. This study was performed according to international validation guidelines, including sensitivity, repeatability, reproducibility, precision, accuracy, contamination assessment, known and case-type samples, and degradation studies. Characterization of the genetic markers, species specificity, and population studies had already been conducted. Moreover, case-type samples were quantified, amplified using commercial kits and the number of alleles detected was recorded. Sensitivity was shown to be 10 pg/µL. Standard curve replicates demonstrated the assay is accurate, precise, as well as fairly repeatable and reproducible. The NGM Detect kit was shown to yield higher peaks than Identifiler Plus and NGM Select for degraded samples. Moreover, quality sensors were always present and proved useful. The quantification values of the large target showed a correlation with the number of alleles detected in the STR profiles for known and casework samples. The degradation index was shown to be informative, with a value of 10 or higher indicating dropout. It is suggested that after quantitation, samples with low or degraded DNA be amplified using newer amplification kits containing quality sensors to confirm that the low-quality profile was not affected by inhibition.
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http://dx.doi.org/10.1002/elps.201900360DOI Listing
May 2020

Male lineages in Brazilian populations and performance of haplogroup prediction tools.

Forensic Sci Int Genet 2020 01 15;44:102163. Epub 2019 Oct 15.

DNA Diagnostic Laboratory (LDD), State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil.

The use of Y-chromosomal genetic markers in forensic investigations demands the establishment of reliable and representative DNA databases of different reference populations. The genetic characterization of the Y chromosome variation in human populations requires the analyses of haplotype frequencies allied to haplogroup determination. The present study aimed to contribute to the Brazilian database by providing 1,382 Yfiler Plus individual profiles, from 11 Brazilian states. The Yfiler Plus markers showed high haplotype diversities in all Brazilian populations (>0.9970), allowing high intra-population discrimination in forensic investigations. Pairwise genetic distances showed a homogeneity between Brazilian populations (F ≤ 0.0043; non-differentiation p-values ≥ 0.0212), indicating that admixed populations from Brazil can be represented in a single Yfiler Plus haplotype database, for forensic purposes. The performance of Haplogroup Predictor and NevGen software in haplogroup prediction based on Yfiler Plus and Yfiler haplotypes was evaluated in a subset of 416 Brazilian samples that were also genotyped for 51 Y-SNPs. In 25% of the samples, no classification or errors were found for at least one of the prediction tools or marker sets. NevGen presented lower error rates (5.52% and 8.65% with Yfiler Plus and Yfiler, respectively) than Haplogroup Predictor (16.11% with Yfiler Plus and 13.70% with Yfiler). In conclusion, both haplogroup prediction tools can be useful to direct the SNP typing, but present large error rates to be used in forensic analysis, especially in predicting African haplogroups in admixed South American populations.
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http://dx.doi.org/10.1016/j.fsigen.2019.102163DOI Listing
January 2020

Living with the dead: A case report and review of the literature.

J Forensic Leg Med 2019 Feb 7;62:107-111. Epub 2019 Feb 7.

University of Brescia, Department of Medical and Surgical Specialties(,) Radiological Sciences and Public Health, Forensic Medicine Unit, Brescia, Italy.

The discovery of human corpses in urban domestic settings does not constitute an unusual case in criminal casework. These scenarios can be very challenging to investigate since the uninformative evidences encountered also demand a multidisciplinary effort among several specialties in the forensic sciences field. The occurrence of this incident is usually accompanied by social isolation, which is an emblematic aspect of urban modern society. The elderly population is especially susceptible to being socially isolated, which is associated with higher mortality. We present a case report of an elderly woman who had been living with her husband's dead body, contributing to the scarce literature on the "Living with the Dead" phenomenon. The use of a multidisciplinary approach and the challenges that social isolation presents to forensic sciences and the contemporary society are discussed.
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http://dx.doi.org/10.1016/j.jflm.2019.02.002DOI Listing
February 2019

Forensic DNA typing from teeth using demineralized root tips.

Forensic Sci Int 2017 Nov 12;280:164-168. Epub 2017 Oct 12.

Cuiabá University - UNIC, Avenida Beira Rio, 3100, Cuiabá, Brazil. Electronic address:

Teeth are widely used samples in forensic human genetic identification due to their persistence and practical sampling and processing. Their processing, however, has changed very little in the last 20 years, usually including powdering or pulverization of the tooth. The objective of this study was to present demineralized root tips as DNA sources while, at the same time, not involving powdering the samples or expensive equipment for teeth processing. One to five teeth from each of 20 unidentified human bodies recovered from midwest Brazil were analyzed. Whole teeth were demineralized in EDTA solution with daily solution change. After a maximum of approximately seven days, the final millimeters of the root tip was excised. This portion of the sample was used for DNA extraction through a conventional organic protocol. DNA quantification and STR amplification were performed using commercial kits followed by capillary electrophoresis on 3130 or 3500 genetic analyzers. For 60% of the unidentified bodies (12 of 20), a full genetic profile was obtained from the extraction of the first root tip. By the end of the analyses, full genetic profiles were obtained for 85% of the individuals studied, of which 80% were positively identified. This alternative low-tech approach for postmortem teeth processing is capable of extracting DNA in sufficient quantity and quality for forensic casework, showing that root tips are viable nuclear DNA sources even after demineralization.
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http://dx.doi.org/10.1016/j.forsciint.2017.10.003DOI Listing
November 2017