Evaluation of Library Preparation Workflows and Applications to Different Sample Types Using the PowerSeq® 46GY System with Massively Parallel Sequencing

This project evaluated the prototype PowerSeq^® 46GY System using donor DNA and casework-type samples. The goal of this study was to determine whether modifications to the manufacturer's protocol could increase read coverage and improve sample results. Buccal and casework-type libraries were prepared using the TruSeq^® DNA PCR-Free HT kit or the KAPA HyperPrep kit. Both kits were evaluated unmodified, and by substituting AMPure^® XP beads for the beads of the most optimal kit. Two qPCR kits, the PowerSeq^® Quant MS System and KAPA Library Quantification Kit, were also evaluated along with a KAPA size-adjustment workbook, which was compared as a third quantification method. Libraries were sequenced using the MiSeq^® FGx and data were analyzed with STRait Razor. Results suggested that all three quantification methods overestimated library concentration, but the PowerSeq kit was most accurate. Samples prepared with the TruSeq library kit provided the highest coverage and the fewest instances of dropout and below-threshold alleles compared with the KAPA kit. Additionally, all bone and hair samples demonstrated full profile completeness, with bone samples yielding a higher average coverage than hair samples. Overall, our study demonstrated that the 46GY manufacturer's protocol produced the best quality results compared to alternative library preparation options.

Recovery of DNA from fired and unfired cartridge casings: comparison of two DNA collection methods

For over 10 years, various studies have attempted to increase the recovery of DNA from ammunition by modifying the DNA collection, extraction, purification, and amplification procedures, with varying levels of success. This study focused on the "soaking" method of Montpetit & O'Donnell [1] and the "rinse-and-swab" method of Bille et al. [2]. First, testing for the presence of exogenous DNA, 210 boxed cartridges (brass, steel, and nickel-plated) from nine manufacturers were swabbed and DNA was extracted, concentrated, and quantified. Extracts that quantified > 0 ng/µL (44 of 210) were amplified and genotyped with GlobalFiler™. Of those, only one extract yielded two alleles indicating that the manufacturing and packaging of ammunition was virtually DNA free. Next, to obtain a baseline comparison of two DNA collection methods on a non-metallic substrate and identify a suitable number of cells to spot on cartridges, different DNA input amounts of primary human adult epidermal keratinocytes (HEKa) were tested. Thereafter, 300 brass and 300 nickel-plated, cartridges were spotted with HEKa cells containing ~5 ng of DNA, fired or unfired, and processed with either method. Finally, five methods representing hybrids of the soaking and rinse-and-swab methods were tested to determine if variations of those methods could be used to increase DNA yield and recovery. The results show that the soaking method consistently yielded more DNA than the rinse-and-swab method from a non-metallic substrate. However, the comparison study demonstrated that both methods performed comparably for cartridges. On average, the soaking method recovered 0.25 ng of DNA (5.1% recovery) and the rinse-and-swab method recovered 0.28 ng (5.8% recovery). However, average recoveries were significantly different among three analysts and considerable variation in yields were observed, possibly due to storage time. Furthermore, consistent with prior reports, the DNA recovered from brass casings was only 16% of that recovered from nickel-plated casings and the average yield of DNA from fired casings was reduced to 67% of unfired casings. Moreover, DNA extracts from brass or nickel-plated casings did not appear to contain amplification inhibitors and only 30/596 appeared severely degraded. Finally, both the published rinse-and-swab and soaking methods yielded more DNA than all modifications of the two methods. Overall, both methods yielded equivalent DNA quantities. Additionally, recovery of DNA from any given cartridge casing may be dependent on storage time as well as the skill, proficiency, and experience of the analyst and may reflect stochastic effects, particularly for casings containing low copy and/or degraded DNA.

Mitochondrial DNA analysis of the putative skeletal remains of Sieur de Marle: Genetic support for anthropological assessment of biogeographic ancestry

In 1932, seven burials were discovered on a Texas plantation that was originally the site of a 17th-century Caddo Indian village. Of the seven excavated graves, one set of remains (an adult male) was notably buried in a manner inconsistent with traditional Caddoan burial practices and has long been purported to be the remains of Sieur de Marle (a member of the French explorer La Salle's last expedition). Diary accounts of La Salle's expedition scribe report that Sieur de Marle died along a river near an Indian village during a trek to Canada to find help for colonists left behind at the ill-fated Fort St. Louis. Additionally, two lead projectiles recovered from the grave were ballistically analyzed and determined to be consistent with ammunition used in 17th-century weaponry. In the 1980s, anthropologists requested access to the remains for study, but the skull was missing. Cranial measurements recorded in 1940 and 1962 (by two independent anthropologists) were used to investigate the ancestry of this individual; and the Giles-Elliot (G-E) discriminant function was calculated to be 18.1, within the Anglo-European range. Dietary isotope testing on non-cranial skeletal elements determined that this unknown male's diet was rich in animal/marine protein sources, which differs appreciably from Caddo Indian populations of that time period. In order to genetically assess this individual's biogeographic ancestry and to provide further support that this individual is of European descent, mitochondrial DNA (mtDNA) sequencing was performed using the Applied Biosystems™ Precision ID mtDNA Whole Genome Panel. mtDNA sequencing of multiple sections from two different long bones yielded compiled results consistent with either Haplogroup H or R, both predominantly European mtDNA haplogroups. Further anthropological calculations were conducted using cranial measurements, FORDISC™ software, and discriminant function analysis. Two-way, four-way, and multigroup discriminant function analyses further classify this set of unidentified remains as being White (European) in origin, with posterior probabilities of 0.999, 0.881 and 0.986, respectively. Combined with historical records of Sieur de Marle's death, as well as overlays of historical and contemporary maps which demonstrate that the plantation site aligns with Joutel's diary accounts of de Marle's burial, these collective results support that these remains are of a European male and may possibly belong to this prominent member of La Salle's expedition team.

Utility of the Ion S5™ and MiSeq FGx™ sequencing platforms to characterize challenging human remains

Often in missing persons' and mass disaster cases, the samples remaining for analysis are hard tissues such as bones, teeth, nails, and hair. These remains may have been exposed to harsh environmental conditions, which pose challenges for downstream genotyping. Short tandem repeat analysis (STR) via capillary electrophoresis (CE) is still the gold standard for DNA typing; however, a newer 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. In this study, bone and tooth samples exposed to a variety of DNA insults (cremation, embalming, decomposition, thermal degradation, and fire) were assessed and sequenced using the Precision ID chemistry and a custom AmpliSeq™ STR and iiSNP panel on the Ion S5™ System, and the ForenSeq DNA Signature Prep Kit on the MiSeq FGx™ system, as well as the GlobalFiler™ PCR Amplification Kit on the 3500™ Genetic Analyzer. The results demonstrated that using traditional CE-based genotyping performed as expected, producing a partial or full DNA profile for all samples, and that both sequencing chemistries and platforms were able to recover sufficient STR and SNP information from a majority of the same challenging samples. Run metrics including profile completeness and mean read depth produced good results with each system, considering the degree of damage of some samples. Most sample insults (except decomposed) produced similar numbers of alleles for both MPS systems. Comparable markers produced full concordance between the two platforms.

Assessment of impact of DNA extraction methods on analysis of human remain samples on massively parallel sequencing success

Skeletal remains recovered from missing persons' cases are often exposed to harsh environmental conditions resulting in the DNA being damaged, degraded, and/or the samples containing PCR inhibitors. In this study, the efficacy of common extraction methods was evaluated to remove high levels of PCR inhibitors commonly encountered with human remains, and their downstream compatibility with the two leading sequencing chemistries and platforms for human identification purposes. Blood, hair, and bone samples were spiked with high levels of inhibitors commonly identified in each particular substrate in order to test the efficiency of various DNA extraction methods prior to sequencing. Samples were extracted using three commercial extraction kits (DNA IQ™, DNA Investigator, and PrepFiler® BTA), organic (blood and hair only), and two total demineralization protocols (bone only)). Massively parallel sequencing (MPS) was performed using two different systems: Precision ID chemistry and a custom AmpliSeq™ STR and iiSNP panel on the Ion S5™ System and the ForenSeq DNA Signature Prep Kit on the MiSeq FGx™. The overall results showed that all DNA extraction methods were efficient and are fully compatible with both MPS systems. Key performance indicators such as STR and SNP reportable alleles, read depth, and heterozygote balance were comparable for each extraction method. In samples where CE-based STRs yielded partial profiles (bone), MPS-based STRs generated more complete or full profiles. Moreover, MPS panels contain more STR loci than current CE-based STR kits and also include SNPs, which can further increase the power of discrimination obtained from these samples, making MPS a desirable choice for the forensic analysis of such challenging samples.