A collaborative study on the precision of the Markov chain Monte Carlo algorithms used for DNA profile interpretation.

Several fully continuous probabilistic genotyping software (PGS) use Markov chain Monte Carlo algorithms (MCMC) to assign weights to different proposed genotype combinations at a locus. Replicate interpretations of the same profile in these software are expected not to produce identical weights and likelihood ratio (LR) values due to the Monte Carlo aspect. This paper reports a detailed precision study under reproducibility conditions conducted as a collaborative exercise across the National Institute of Standards and Technology (NIST), Federal Bureau of Investigation (FBI), and Institute of Environmental Science and Research (ESR).

Assessment of the ANDE 6C Rapid DNA system and investigative biochip for the processing of calcified and muscle tissue.

The ANDE 6C Rapid DNA system could offer a potential alternative for the processing of calcified and soft tissue samples, often encountered in mass disaster scenarios. While originally designed for single source buccal swabs, interest in the performance of these instruments when using other types of single source samples continues to grow. To enhance the recovery of otherwise lesser quality samples, the manufacturer developed the investigative biochip, an alternative to the NDIS approved Arrestee biochip for reference sample buccal swabs.

Modeling allelic analyte signals for aSTRs in NGS DNA profiles.

We describe an adaption of Bright et al.'s work modeling peak height variability in CE-DNA profiles to the modeling of allelic aSTR (autosomal short tandem repeats) read counts from NGS-DNA profiles, specifically for profiles generated from the ForenSeq™ DNA Signature Prep Kit, DNA Primer Mix B. Bright et al.

Assessing the impact of using conventional swabs on the ANDE 6C arrestee biochip.

Rapid DNA technology will provide law enforcement booking personnel the ability to process and query reference samples obtained from qualifying arrestees against unsolved crimes of special concern in real-time, potentially enhancing the speed of an investigation. The technology could also be utilized within the laboratory setting to expedite the processing of reference samples submitted with a case. Validation studies have found that when used with reference samples, the ANDE 6C Rapid DNA technology generates successful profiles that are concordant to orthogonal system generated data ∼85 % of the time.

Variability and additivity of read counts for aSTRs in NGS DNA profiles.

There has been an increase in the number of laboratories and researchers adopting new sequencing technologies, known as next-generation sequencing (NGS). An understanding of the behaviour of NGS DNA profiles is needed to enable for the development of probabilistic genotyping methods for the interpretation of such profiles. In this work, we investigate NGS analyte signal variation, specifically heterozygous balance and stutter variability from profiles generated using the ForenSeq™ DNA Signature Prep Kit, DNA Primer Mix B.

Results of the 2018 Rapid DNA Maturity Assessment.

Three commercially available integrated rapid DNA instruments were tested as a part of a rapid DNA maturity assessment in July of 2018. The assessment was conducted with sets of blinded single-source reference samples provided to participants for testing on the individual rapid platforms within their laboratories. The data were returned to the National Institute of Standards and Technology (NIST) for review and analysis.

A closer look at Verogen's Forenseq™ DNA Signature Prep kit autosomal and Y-STR data for streamlined analysis of routine reference samples.

Massively parallel sequencing (MPS) provides forensic DNA laboratories an option to overcome the limitations associated with CE and current STR assays. Verogen's MPS Forenseq DNA Signature kit concomitantly amplifies 27 autosomal, 7 X-, and 24 Y-STRs. In addition, 94 identity, 56 ancestry, and 22 phenotypic-informative SNPs are included for a total of over 200 markers in one multiplex.

Internal validation of the DNAscan/ANDE™ Rapid DNA Analysis™ platform and its associated PowerPlex 16 high content DNA biochip cassette for use as an expert system with reference buccal swabs.

Rapid DNA platforms are fully integrated systems capable of producing and analyzing short tandem repeat (STR) profiles from reference sample buccal swabs in less than two hours. The technology requires minimal user interaction and experience making it possible for high quality profiles to be generated outside an accredited laboratory. The automated production of point of collection reference STR profiles could eliminate the time delay for shipment and analysis of arrestee samples at centralized laboratories.

Performance and concordance of the ForenSeq™ system for autosomal and Y chromosome short tandem repeat sequencing of reference-type specimens.

Though the utility of next-generation sequencing (NGS) technologies for forensic short tandem repeat (STR) typing has been evident for several years, commercially available assays and software solutions developed specifically to meet forensic needs have only recently become available. One of these, the ForenSeq™ DNA Signature Prep Kit (Illumina, Inc.) sequences 27 autosomal STR (aSTR) and 24 Y chromosome STR (Y-STR) loci (concurrent with additional nuclear markers) per multiplexed sample, with automated secondary and tertiary analyses of the data accomplished via the associated ForenSeq™ Universal Analysis Software (UAS).

The use of direct analysis in real time (DART) to assess the levels of inhibitors co-extracted with DNA and the associated impact in quantification and amplification.

The measure of quality in DNA sample processing starts with an effective nucleic acid isolation procedure. Most problems with DNA sample typing can be attributed to low quantity DNA and/or to the presence of inhibitors in the sample. Therefore, establishing which isolation method is best at removing potential inhibitors may help overcome some of the problems analysts encounter by providing useful information in the determination of the optimal approach for any given sample.

Population data on the expanded CODIS core STR loci for eleven populations of significance for forensic DNA analyses in the United States.

Allele distributions for twenty-three autosomal short tandem repeat (STR) loci - D1S1656, D2S441, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D10S1248, D12S391, D13S317, D16S539, D18S51, D19S433, D21S11, D22S1045, CSF1PO, FGA, Penta D, Penta E, SE33, TH01, TPOX and vWA - were determined in Caucasians, Southwestern Hispanics, Southeastern Hispanics, African Americans, Bahamians, Jamaicans, Trinidadians, Chamorros, Filipinos, Apaches, and Navajos. The data are included in the FBI PopStats software for calculating statistical estimates of DNA typing results and cover the expanded CODIS Core STR Loci required of U.S.

Massively parallel sequencing of complete mitochondrial genomes from hair shaft samples.

Though shed hairs are one of the most commonly encountered evidence types, they are among the most limited in terms of DNA quantity and quality. As a result, DNA testing has historically focused on the recovery of just about 600 base pairs of the mitochondrial DNA control region. Here, we describe our success in recovering complete mitochondrial genome (mtGenome) data (∼16,569bp) from single shed hairs.

Determination of an effective housekeeping gene for the quantification of mRNA for forensic applications.

The potential application of mRNA for the identification of biological fluids using molecular techniques has been a recent development in forensic serology. Constitutively expressed housekeeping genes can assess the amount of mRNA recovered from a sample, establish its suitability for downstream applications, and provide a reference point to corroborate the identity of the fluid. qPCR was utilized to compare the expression levels of housekeeping genes from forensic-like body fluid stains to establish the most appropriate assessment of human mRNA quantity prior to profiling.

The application of amplicon length heterogeneity PCR (LH-PCR) for monitoring the dynamics of soil microbial communities associated with cadaver decomposition.

The placement of cadavers in shallow, clandestine graves may alter the microbial and geochemical composition of the underlying and adjacent soils. Using amplicon length heterogeneity-PCR (LH-PCR) the microbial community changes in these soils can be assessed. In this investigation, nine different grave sites were examined over a period of 16weeks.

Archaeal and bacterial communities respond differently to environmental gradients in anoxic sediments of a California hypersaline lake, the Salton Sea.

Sulfidic, anoxic sediments of the moderately hypersaline Salton Sea contain gradients in salinity and carbon that potentially structure the sedimentary microbial community. We investigated the abundance, community structure, and diversity of Bacteria and Archaea along these gradients to further distinguish the ecologies of these domains outside their established physiological range. Quantitative PCR was used to enumerate 16S rRNA gene abundances of Bacteria, Archaea, and Crenarchaeota.

Ocular Adnexal Lymphoma: no evidence for bacterial DNA associated with lymphoma pathogenesis.

Ocular Adnexal Lymphomas (OALs) are the most common tumors of the eye, the majority being extranodal mucosa-associated lymphoid tissue (MALT) lymphomas. Association with Chlamydia psittaci was described in some geographic areas. OAL response to antibiotic therapy was reported in cases not harboring Chlamydia psittaci DNA, suggesting that other bacterial infection might be implicated in the pathogenesis.

Microbial metagenome profiling using amplicon length heterogeneity-polymerase chain reaction proves more effective than elemental analysis in discriminating soil specimens.

The combination of soil's ubiquity and its intrinsic abiotic and biotic information can contribute greatly to the forensic field. Although there are physical and chemical characterization methods of soil comparison for forensic purposes, these require a level of expertise not always encountered in crime laboratories. We hypothesized that soil microbial community profiling could be used to discriminate between soil types by providing biological fingerprints that confer uniqueness.