Forensic DNA typing from teeth using demineralized root tips

•Teeth are widely used samples in forensic DNA analysis.•Grinding teeth has been massively carried out for more than 20 years.•Extracting DNA from demineralized root tips is enough for full STR profiles.•60% of the samples yielded a full STR profile after the first extraction.•The low-tech approach...

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Bibliographic Details
Published in:Forensic science international 2017-11, Vol.280, p.164-168
Main Authors: Corrêa, Heitor Simões Dutra, Pedro, Fabio Luis Miranda, Volpato, Luiz Evaristo Ricci, Pereira, Thiago Machado, Siebert Filho, Gilberto, Borges, Álvaro Henrique
Format: Article
Language:English
Subjects:
Analyzers
Bone demineralization technique
Capillary electrophoresis
Demineralization
Demineralizing
Deoxyribonucleic acid
DNA
Ethylenediaminetetraacetic acids
Forensic engineering
Forensic genetics
Forensic osteology
Forensic science
Forensic sciences
Identification
Identity
Laboratories
Microsatellite repeats
Odontology
Powdering
Teeth
Tips
Tooth
Typing
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Summary:•Teeth are widely used samples in forensic DNA analysis.•Grinding teeth has been massively carried out for more than 20 years.•Extracting DNA from demineralized root tips is enough for full STR profiles.•60% of the samples yielded a full STR profile after the first extraction.•The low-tech approach is a valuable alternative for developing countries. 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.
ISSN:0379-0738
1872-6283
DOI:10.1016/j.forsciint.2017.10.003