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Zavala EI, Rajagopal S, Perry GH, Kruzic I, Bašić Ž, Parsons TJ, Holland MM. Impact of DNA degradation on massively parallel sequencing-based autosomal STR, iiSNP, and mitochondrial DNA typing systems. Int J Legal Med 2019; 133:1369-1380. [PMID: 31267160 DOI: 10.1007/s00414-019-02110-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022]
Abstract
Biological samples, including skeletal remains exposed to environmental insults for extended periods of time, exhibit increasing levels of DNA damage and fragmentation. Human forensic identification methods typically use a combination of mitochondrial (mt) DNA sequencing and short tandem repeat (STR) analysis, which target segments of DNA ranging from 80 to 500 base pairs (bps). Larger templates are often unavailable as skeletal samples age and the associated DNA degrades. Single-nucleotide polymorphism (SNP) loci target shorter templates and may serve as a solution to the problem. Recently developed assays for STR and SNP analysis using a massively parallel sequencing approach, such as the ForenSeq kit (Verogen, San Diego, CA), offer a means for generating results from degraded samples as they target templates down to 60 to 170 bps. We performed a modeling study that demonstrates that SNPs can increase the significance of an identification when analyzing DNA down to an average size of 100 bps for input amounts between 0.375 and 1 ng of nuclear DNA. Observations from this study were then compared with human skeletal material results (n = 14, ninth to eighteenth centuries), which further demonstrated the utility of the ForenSeq kit for degraded samples. The robustness of the Promega PowerSeq™ Mito System was also tested with human skeletal remains (n = 70, ninth to eighteenth centuries), resulting in successful coverage of 99.29% of the mtDNA control region at 50× coverage or more. This was accompanied by modifications to a mainstream DNA extraction technique for skeletal remains that improved recovery of shorter templates.
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Affiliation(s)
- Elena I Zavala
- Department of Biochemistry and Molecular Biology, Forensic Science Program, Pennsylvania State University, State College, PA, USA.
| | - Swetha Rajagopal
- Department of Biochemistry and Molecular Biology, Forensic Science Program, Pennsylvania State University, State College, PA, USA.,Department of Forensic Science, John Jay College of Criminal Justice, New York, NY, USA
| | - George H Perry
- Departments of Anthropology and Biology, Pennsylvania State University, State College, PA, USA
| | - Ivana Kruzic
- University Department of Forensic Sciences, University of Split, Split, Croatia
| | - Željana Bašić
- University Department of Forensic Sciences, University of Split, Split, Croatia
| | - Thomas J Parsons
- International Commission on Missing Persons, The Hague, Netherlands
| | - Mitchell M Holland
- Department of Biochemistry and Molecular Biology, Forensic Science Program, Pennsylvania State University, State College, PA, USA
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