The recovery of usable host DNA from burned human remains in forensic contexts can provide essential information for establishing a biological profile and identity (e. g., Tomsia et al., 2022, Hartman et al. 2011; Hollard et al. 2017). However, exposure to extreme temperature causes bone discoloration, warping, fracture and fragmentation resulting in significant challenges for identification (Zapico and Stone-Gordon, 2023; de Boer et al. 2020; Byard et al. 2012; Schmidt and Symes 2015; Ubelaker 2009). Current guidelines for disaster victim identification recommend samples from blood, mouth swabs or deep red muscle tissue when the body is not decomposed and dense tissues such as long compact bone, cortical bone, and dentin (from whole teeth) when decomposed or fragmented (Prinz et al., 2007). Where there is severe burning, the complete removal and/or decontamination of the exterior surfaces of recovered bone, including any adhering carbonized soft tissue is recommended as these surfaces are often considered to be excessively susceptible to exogenous contamination (McKinnon et al. 2021; de Boer et al., 2020; Prinz et al. 2007). This protocol has resulted in a limited understanding of the potential DNA recovery from severely thermally altered soft tissue. Here, we examine DNA recovery from severely burned (e.g., completely carbonized) soft-tissue (n = 46) adhering to the exterior surfaces of burned skeletal remains using the Qiagen Blood and Tissue kit and assess its potential viability as a sampling substrate in downstream STR. analysis In addition, we compare these results with those from the underlying skeletal tissues where DNA recovery was performed using two extraction methods, the complete demineralization protocol introduced by Loreille and colleagues (Loreille et al., 2007; Loreille et al., 2010) and a modified silica column extraction protocol (Dabney et al., 2013; Dabney et al., 2019, Velsko et al., 2020). The first protocol is commonly used in forensic analyses of degraded samples (e.g. Loreille et al. 2011), while the second was developed for ancient DNA sample processing (e.g. Parker et al., 2020; Nieves Colon et al 2018; Orlando et al., 2021). Our comparisons of total DNA, endogenous DNA, and STR loci recovery indicate that this carbonized soft tissue is equally viable as a substrate for DNA identification, particularly at relatively low-medium levels of burning. Thus, rather than being discarded, burned soft tissue should be preferentially sampled given that they are relatively easier and cheaper to analyze.

Authors

• Erin M. Rawls (School of Life Sciences, Arizona State University, United States of America)
• Amber Coffman (Othram Inc, United States of America)
• Cody Parker (School of Human Evolution and Social Change, Arizona State University, United States of America)
• Adam B. Rohrlach (Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology, Germany)
• Robert Oldt (School of Interdisciplinary Forensics, Arizona State University, United States of America)
• Miriam G. Foster (Department of Biochemistry & Molecular Biology, Forensic Science Program, The Pennsylvania State University, United States of America)
• Katelyn Bohlhofner (Office of the Medical Examiner, Maricopa County, United States of America)
• Giovanna Vidoli (Forensic Anthropology Center, Department of Anthropology, University of Tennessee, United States of America)
• Joanne Devlin (Forensic Anthropology Center, Department of Anthropology, University of Tennessee, United States of America)
• Mitchell M. Holland (Department of Biochemistry & Molecular Biology, Forensic Science Program, The Pennsylvania State University, United States of America)
• Sreetharan Kanthaswamy (School of Interdisciplinary Forensics, Arizona State University, United States of America)
• Anne C. Stone (Center for Evolution and Medicine, Arizona State University, United States of America)