Shane Watson* and Emily Pitt
Hard tissues like bones, teeth, nails, and hair are sometimes the only samples left for study in situations involving missing people and large-scale disasters. It may have been difficult to genotype these remnants in the aftermath of extreme environmental exposure. However, a more recent technology known as Massively Parallel Sequencing (MPS) could improve upon our current techniques by typing different and more markers in a single analysis, and consequently improving the power of discrimination. Short Tandem Repeat analysis (STR) via Capillary Electrophoresis (CE) is still the gold standard for DNA typing. In this study, bone and tooth samples that had been subjected to a variety of DNA insults (cremation, embalming, decomposition, thermal degradation, and fire) were evaluated and sequenced using the Precision ID chemistry and a custom AmpliSeqTM STR and iiSNP panel on the Ion S5TM System, the ForenSeq DNA Signature Prep Kit on the MiSeq FGXTM system, as well as the GlobalFilerTM. The findings showed that conventional CE-based genotyping operated as anticipated, resulting in a partial or complete DNA profile for every sample, and that both sequencing chemistries and platforms were able to recover enough STR and SNP information from the majority of the same difficult samples. Considering the degree of damage to some samples, run measures such as profile completeness and mean read depth delivered good results with each system. For both MPS systems, the majority of sample insults—aside from decomposed—produced around the same amount of alleles. Similar markers resulted in perfect agreement between the two platforms.