Contents lists available at ScienceDirect Legal Medicine journal homepage: www.elsevier.com/locate/legalmed DNA extraction of urinary bladder swabs collected from carbonized and decomposing corpses: Possible application in disaster victim identification Felipe C.A. Brito a , Marcilto R. Nunes b , David R.B.M. Prata b , Sandra F.P. Martha c , Carolina Bottino c, ⁎ , Rodrigo G. Garrido a,c a Post Graduate Studies in Genetics and Molecular Biology (Pós Graduação em Genética e Biologia Molecular), UNIRIO, Rio de Janeiro, Brazil b Afrânio Peixoto Forensics Medical Institute (Instituto Médico Legal Afrânio Peixoto), IMLAP/PCERJ, Rio de Janeiro, Brazil c Forensic Genetics Research Institute (Instituto de Pesquisa e Perícias em Genética Forense), IPPGF/PCERJ, Rio de Janeiro, Brazil ARTICLE INFO Keywords: Urinary bladder Human identification DVI ABSTRACT A disaster is an unexpected event causing death or injury to many people. In such events, a large number of casualties may take place, exposing corpses to a harsh environment for days or months. DNA profiling is re- cognized as one of the primary methods for identifying mass disaster victims, especially when it involves de- composed or fragmented bodies. The objective of this study was to standardize the use of urinary bladder swabs as a source of DNA for the identification of decomposing and carbonized human bodies by Forensic Genetic techniques. Samples’ DNA was extracted using both organic and Chelex® resin methods; quantified by qPCR and amplified with PowerPlex® Fusion System (Promega Corporation). The results of this study show that between the two methodologies used for DNA extraction, the organic method presented higher DNA yields in relation to the minimum acceptable for the amplification, while Chelex®, although not having a high yield, still allowed obtaining significant amounts of DNA for amplification. The use of bladder swabs has proven to be a viable source of DNA for human identification, since besides reproducible and reliable results, this type of sample allows a significant reduction in the time and cost required for analysis. 1. Introduction Disasters are catastrophic and unexpected events that result in the injury or death of many people. The process of identifying all victims of a disaster is known as disaster victim identification (DVI) and is es- sential in forensic analysis [1,2]. As part of the DVI response, DNA analysis is one of the main strategies used for victim identification [2,3]. However, factors such as the level of preservation of the body, environmental conditions, and other associated factors may impair the quality of the genetic material obtained [3,4]. Since 2009, ISFG and Interpol have recommended the use of bladder swabs from carbonized victims as a source of DNA [3,5], but this type of sample still isn’t routinely used. A previous study of our group de- monstrated the feasibility of using bladder swabs for identifying human corpses with short post-mortem intervals, without evident signs of pu- trefaction or carbonization [6]. In the state of Rio de Janeiro, most homicide victims are found carbonized and are usually involved in conflicts related to drug traf- ficking [7]. In contrast, because of the hot and humid climate of the state and its extensive coastline, many corpses are found in an advanced state of decomposition [8]. The sampling of bladder swabs for identi- fying such bodies by DNA analysis may improve sampling, storage, transport, and manipulation [6]. The objective of this study was to assess the viability of using bladder swabs as a source of DNA for identifying carbonized and se- verely decomposed bodies by comparing two different methods of DNA extraction—phenol: chloroform: isoamyl alcohol (organic) and Chelex® resin—according to the recommendation of ISFG and the Interpol. 2. Material and methods Samples from 10 decomposing bodies and 10 carbonized bodies were collected at Afrânio Peixoto Forensic Medical Institute (Instituto Médico Legal Afrânio Peixoto (IMLAP), in Rio de Janeiro, Brazil, and included bladder swabs, bones and muscles. DNA from bone and muscle samples were extracted by the organic method with phenol: chloroform [9]; bladder swabs were extracted with either the organic method or the Chelex 100® resin method (Bio- Rad) [9]. DNA degradation was evaluated with the High Sensitivity DNA Kit in the Agilent 2100 Bioanalyzer system. DNA was quantified https://doi.org/10.1016/j.legalmed.2018.12.002 Received 25 June 2018; Received in revised form 16 November 2018; Accepted 16 December 2018 ⁎ Corresponding author at: IPPGF/PCERJ, Rua Marquês de Pombal, 150, Cidade Nova, Rio de Janeiro/RJ, Brazil. E-mail address: carolina.bottino.bio@gmail.com (C. Bottino). Legal Medicine 37 (2019) 15–17 Available online 17 December 2018 1344-6223/ © 2018 Elsevier B.V. All rights reserved. T