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.

Copan microFLOQ® Direct Swab collection of bloodstains, saliva, and semen on cotton cloth.

The microFLOQ® Direct Swab was tested by sampling diluted blood, semen, and saliva stains deposited on cotton cloth. DNA typing was performed using the PowerPlex® Fusion 6C System by direct PCR or a modified direct PCR. Direct PCR of swabs sampled the center of a stain, compared to their respective edge samplings, and had higher profile completeness and total relative fluorescent units (RFU) for all dilutions of blood and semen stains tested. The modified direct PCR used template DNA eluted from the swab head using the Casework Direct Kit, Custom and washes either contained 1-thioglycerol (TG) additive or no TG. Modified direct PCR had mixed results for blood, saliva, and semen stains, with semen stains showing significant differences in profile completeness (5% and 1%) and total RFU (neat, 5% and 1%) with the addition of TG to the Casework Direct Reagent. No significant difference was seen in any dilution of blood or saliva stains processed with the modified direct PCR, but profile completeness and total RFU were improved overall compared to stains swabbed with cotton swabs or 4N6FLOQSwabs™. This study supports the hypothesis that the microFLOQ® Direct Swab is able to collect minute amounts of DNA from cotton cloth and may be considered as an alternate pre-screening methodology in forensic biology casework.

Forensic genetic investigation of human skeletal remains recovered from the La Belle shipwreck.

In 1995, the historical shipwreck of La Belle was discovered off the coast of Texas. One partial human skeleton was recovered from alongside cargo in the rear portion of the ship; a second (complete) skeleton was found atop coiled anchor rope in the bow. In late 2015, comprehensive forensic genetic testing began on multiple samplings from each set of remains. For the partial skeleton recovered from the ship's rear cargo area, results were obtained for 26/27 Y-STRs using traditional CE; with MPS technology, results were obtained for 18/24 Y-STRs, 56/56 ancestry-informative SNPs (aiSNPs), 22/22 phenotype-informative SNPs (piSNPs), 22/27 autosomal STRs, 4/7 X-STRs, and 94/94 identity-informative SNPs (iiSNPs). For the complete skeleton of the second individual, results were obtained for 7/17 Y-STRs using traditional CE; with MPS technology, results were obtained for 5/24 Y-STRs, 49/56 aiSNPs, 18/22 piSNPs, 15/27 autosomal STRs, 1/7 X-STRs, and 66/94 iiSNPs. Biogeographic ancestry for each set of skeletal remains was predicted using the ancestry feature and metapopulation tool of the Y-STR Haplotype Reference Database (YHRD), Haplogroup Predictor, and the Forensic Research/Reference on Genetics knowledge base (FROG-kb). Phenotype prediction was performed using piSNP data and the HIrisplex eye color and hair color DNA phenotyping webtool. mtDNA whole genome sequencing also was performed successfully. This study highlights the sensitivity of current forensic laboratory methods in recovering DNA from historical and archaeological human remains. Using advanced sequencing technology provided by MiSeq™ FGx (Verogen) and Ion S5™ (Thermo Fisher Scientific) instrumentation, degraded skeletal remains can be characterized using a panel of diverse and highly informative markers, producing data which can be useful in both forensic and genealogical investigations.

A novel phylogenetic approach for de novo discovery of putative nuclear mitochondrial (pNumt) haplotypes.

Current approaches for parsing true variation (i.e. signal) from noise, broadly involve estimating a baseline value of the latter, below which all sequence data are ignored. In an effort to deliver a more objective criterion for setting such thresholds, a novel approach based on phylogenetic principles is presented here., Our method deconstructs a special category of noise from true mitochondrial genome data, namely nuclear insertions of mitochondrial DNA (Numts). This bioinformatic approach leverages the relationship of massively parallel sequence reads and is capable of discovering putative Numts (pNumts) in absence of a reference genome. The new method was tested on a whole mitochondrial genome dataset (n = 41 individuals from an admixed population sample from Rio de Janeiro) and led to the discovery of 451 pNumt variants. Comparison of these pNumts haplotypes against an existing Numt database revealed 147 exact matches to previously discovered Numts, while 122 haplotypes differed only by a single base pair and none matched exclusively to the mitochondrial genome. In general, these sequences were considerably more divergent from the mitochondrial genome than from those of the Numt database, supporting that the novel pNumts were probably hitherto uncatalogued variants. Unlike previous techniques, our method appears to be able to detect both polymorphic and fixed Numt sequences. It was also found that the region containing the D-Loop and associated Promoters (DLP) in the human mitochondrial genome, which harbors markers of forensic genetics importance, is the origin of several Numts. Though currently designed for the mitochondrial genome, our novel approach has the potential to be expanded to other scenarios that might require construing signal from noise, including the deconvolution of mixtures, thus significantly improving how analytical thresholds may be established.

Enhanced interrogation of degraded DNA from human skeletal remains: Increased genetic data recovery using the expanded CODIS loci, multiple sex determination markers, and consensus testing.

Skeletal remains are among the most difficult types of samples encountered in forensic DNA casework and historical investigations due to prolonged exposure to environmental insults. DNA extracted from bone often is degraded, in low quantities, and contains co-purified inhibitors from the surrounding soil and/or burial vault material. When sexually dimorphic skeletal elements are not recovered, determining the sex of a decedent can be challenging. With unidentified human skeletal remains, genetic data often are evaluated in concert with anthropological analyses, as well as other types of metadata, to improve confidence in making associations or for positive identifications. This study evaluated a multi-faceted molecular genetic approach to increasing the amount of data that can be recovered from degraded skeletal remains. Results demonstrate that using a newer-generation multiplex (GlobalFiler™) with an expanded set of highly discriminatory DNA markers - combined with co-amplification of three different sex-determining loci, one additional PCR cycle, and testing multiple cuttings from the same bone or multiple regions within a skeleton - can improve reliability and accuracy in skeletal remains identifications by providing data concordance.

Forensic human identification with targeted microbiome markers using nearest neighbor classification.

From the perspective of forensics genetics, the human microbiome is a rich, relatively untapped resource for human identity testing. Since it varies within and among people, and perhaps temporally, the potential forensic applications of the use of the microbiome can exceed that of human identification. However, the same inherent variability in microbial distributions may pose a substantial barrier to forming predictions on an individual as the source of the microbial sample unless stable signatures of the microbiome are identified and targeted. One of the more commonly adopted strategies for microbial human identification relies on quantifying which taxa are present and their respective abundance levels. It remains an open question if such microbial signatures are more individualizing than estimates of the degree of genetic relatedness between microbial samples. This study attempts to address this question by contrasting two prediction strategies. The first approach uses phylogenetic distance to predict the host individual; thus it operates under the premise that microbes within individuals are more closely related than microbes between/among individuals. The second approach uses population genetic measures of diversity at clade-specific markers, serving as a fine-grained assessment of microbial composition and quantification. Both assessments were performed using targeted sequencing of 286 markers from 22 microbial taxa sampled in 51 individuals across three body sites measured in triplicate. Nearest neighbor and reverse nearest neighbor classifiers were constructed based on the pooled data and yielded 71% and 78% accuracy, respectively, when diversity was considered, and performed significantly worse when a phylogenetic distance was used (54% and 63% accuracy, respectively). However, empirical estimates of classification accuracy were 100% when conditioned on a maximum nearest neighbor distance when diversity was used, while identification based on a phylogenetic distance failed to reach saturation. These findings suggest that microbial strain composition is more individualizing than that of a phylogeny, perhaps indicating that microbial composition may be more individualizing than recent common ancestry. One inference that may be drawn from these findings is that host-environment interactions may maintain the targeted microbial profile and that this maintenance may not necessarily be repopulated by intra-individual microbial strains.

Evaluation of the precision ID mtDNA whole genome panel on two massively parallel sequencing systems.

Sequencing whole mitochondrial genomes by capillary electrophoresis is a costly and time/labor-intensive endeavor. Many of the previous Sanger sequencing-based approaches generated amplicons that were several kilobases in length; lengths that are likely not amenable for most forensic applications. However, with the advent of massively parallel sequencing (MPS) short-amplicon multiplexes covering the entire mitochondrial genome can be sequenced relatively easily and rapidly. Recently, the Precision ID mtDNA Whole Genome Panel (Thermo Fisher Scientific by Applied Biosystems™) has been introduced. This panel is composed of 162 amplicons (in two multiplexes) that are considerably smaller in length (∼163bp) and thus are more amenable to analyzing challenged samples. This panel was evaluated on both the Ion S5™ System (Thermo Fisher Scientific) and the MiSeq™ FGx Desktop Sequencer (Illumina). A script was developed to extract phased haplotypes associated with these amplicons. Levels of read-depth were compared across sequencing pools and between sequencing technologies and haplotype concordances were assessed. Given modest thresholds on read depth, the haplotypes identified by either technology were consistent. Nuclear mitochondrial sequences (Numts) were also inferred, and the effect of different mapping strategies commonly used to filter out Numts were contrasted. Some Numts are co-amplified with this amplification kit, and while the choice of reference sequence can mitigate some of these effects, some data from the mitochondrial genome were lost in the process in this study. This study demonstrates that the Ion and MiSeq platforms provide consistent haplotype estimation of the whole mitochondrial genome, thus providing further support for the reliability and validity of the Precision ID mtDNA Whole Genome Panel.

Improved Y-STR typing for disaster victim identification, missing persons investigations, and historical human skeletal remains.

Bones are a valuable source of DNA in forensic, anthropological, and archaeological investigations. There are a number of scenarios in which the only samples available for testing are highly degraded and/or skeletonized. Often it is necessary to perform more than one type of marker analysis on such samples in order to compile sufficient data for identification. Lineage markers, such as Y-STRs and mitochondrial DNA (mtDNA), represent important systems to complement autosomal DNA markers and anthropological metadata in making associations between unidentified remains and living relatives or for characterization of the remains for historical and archaeological studies. In this comparative study, Y-STR typing with both Yfiler™ and Yfiler™ Plus (Thermo Fisher Scientific, Waltham, MA, USA) was performed on a variety of human skeletal remains, including samples from the American Civil War (1861-1865), the late nineteenth century gold rush era in Deadwood, SD, USA (1874-1877), the Seven Years' War (1756-1763), a seventeenth-century archaeological site in Raspenava, Bohemia (Czech Republic), and World War II (1939-1945). The skeletal remains used for this study were recovered from a wide range of environmental conditions and were extracted using several common methods. Regardless of the DNA extraction method used and the age/condition of the remains, 22 out of 24 bone samples yielded a greater number of alleles using the Yfiler™ Plus kit compared to the Yfiler™ kit using the same quantity of input DNA. There was no discernable correlation with the degradation index values for these samples. Overall, the efficacy of the Yfiler™ Plus assay was demonstrated on degraded DNA from skeletal remains. Yfiler™ Plus increases the discriminatory power over the previous generation multiplex due to the larger set of Y-STR markers available for analysis and buffer modifications with the newer version kit. Increased haplotype resolution is provided to infer or refute putative genetic relationships.

Direct PCR amplification of DNA from human bloodstains, saliva, and touch samples collected with microFLOQ® swabs.

Previous studies have shown that nylon flocked swabs outperform traditional fiber swabs in DNA recovery due to their innovative design and lack of internal absorbent core to entrap cellular materials. The microFLOQ® Direct swab, a miniaturized version of the 4N6 FLOQSwab®, has a small swab head that is treated with a lysing agent which allows for direct amplification and DNA profiling from sample collection to final result in less than two hours. Additionally, the microFLOQ® system subsamples only a minute portion of a stain and preserves the vast majority of the sample for subsequent testing or re-analysis, if desired. The efficacy of direct amplification of DNA from dilute bloodstains, saliva stains, and touch samples was evaluated using microFLOQ® Direct swabs and the GlobalFiler™ Express system. Comparisons were made to traditional methods to assess the robustness of this alternate workflow. Controlled studies with 1:19 and 1:99 dilutions of bloodstains and saliva stains consistently yielded higher STR peak heights than standard methods with 1ng input DNA from the same samples. Touch samples from common items yielded single source and mixed profiles that were consistent with primary users of the objects. With this novel methodology/workflow, no sample loss occurs and therefore more template DNA is available during amplification. This approach may have important implications for analysis of low quantity and/or degraded samples that plague forensic casework.

Results of a collaborative study on DNA identification of aged bone samples.

AIM: A collaborative exercise with several institutes was organized by the Forensic DNA Service (FDNAS) and the Institute of the Legal Medicine, 2nd Faculty of Medicine, Charles University in Prague, Czech Republic, with the aim to test performance of different laboratories carrying out DNA analysis of relatively old bone samples. METHODS: Eighteen laboratories participating in the collaborative exercise were asked to perform DNA typing of two samples of bone powder. Two bone samples provided by the National Museum and the Institute of Archaelogy in Prague, Czech Republic, came from archeological excavations and were estimated to be approximately 150 and 400 years old. The methods of genetic characterization including autosomal, gonosomal, and mitochondrial markers was selected solely at the discretion of the participating laboratory. RESULTS: Although the participating laboratories used different extraction and amplification strategies, concordant results were obtained from the relatively intact 150 years old bone sample. Typing was more problematic with the analysis of the 400 years old bone sample due to poorer quality. CONCLUSION: The laboratories performing identification DNA analysis of bone and teeth samples should regularly test their ability to correctly perform DNA-based identification on bone samples containing degraded DNA and potential inhibitors and demonstrate that risk of contamination is minimized.

More comprehensive forensic genetic marker analyses for accurate human remains identification using massively parallel DNA sequencing.

BACKGROUND: Although the primary objective of forensic DNA analyses of unidentified human remains is positive identification, cases involving historical or archaeological skeletal remains often lack reference samples for comparison. Massively parallel sequencing (MPS) offers an opportunity to provide biometric data in such cases, and these cases provide valuable data on the feasibility of applying MPS for characterization of modern forensic casework samples. In this study, MPS was used to characterize 140-year-old human skeletal remains discovered at a historical site in Deadwood, South Dakota, United States. The remains were in an unmarked grave and there were no records or other metadata available regarding the identity of the individual. Due to the high throughput of MPS, a variety of biometric markers could be typed using a single sample. RESULTS: Using MPS and suitable forensic genetic markers, more relevant information could be obtained from a limited quantity and quality sample. Results were obtained for 25/26 Y-STRs, 34/34 Y SNPs, 166/166 ancestry-informative SNPs, 24/24 phenotype-informative SNPs, 102/102 human identity SNPs, 27/29 autosomal STRs (plus amelogenin), and 4/8 X-STRs (as well as ten regions of mtDNA). The Y-chromosome (Y-STR, Y-SNP) and mtDNA profiles of the unidentified skeletal remains are consistent with the R1b and H1 haplogroups, respectively. Both of these haplogroups are the most common haplogroups in Western Europe. Ancestry-informative SNP analysis also supported European ancestry. The genetic results are consistent with anthropological findings that the remains belong to a male of European ancestry (Caucasian). Phenotype-informative SNP data provided strong support that the individual had light red hair and brown eyes. CONCLUSIONS: This study is among the first to genetically characterize historical human remains with forensic genetic marker kits specifically designed for MPS. The outcome demonstrates that substantially more genetic information can be obtained from the same initial quantities of DNA as that of current CE-based analyses.

Modified DOP-PCR for improved STR typing of degraded DNA from human skeletal remains and bloodstains.

Forensic and ancient DNA samples often are damaged and in limited quantity as a result of exposure to harsh environments and the passage of time. Several strategies have been proposed to address the challenges posed by degraded and low copy templates, including a PCR based whole genome amplification method called degenerate oligonucleotide-primed PCR (DOP-PCR). This study assessed the efficacy of four modified versions of the original DOP-PCR primer that retain at least a portion of the 5' defined sequence and alter the number of bases on the 3' end. The use of each of the four modified primers resulted in improved STR profiles from environmentally-damaged bloodstains, contemporary human skeletal remains, American Civil War era bone samples, and skeletal remains of WWII soldiers over those obtained by previously described DOP-PCR methods and routine STR typing. Additionally, the modified DOP-PCR procedure allows for a larger volume of DNA extract to be used, reducing the need to concentrate the sample and thus mitigating the effects of concurrent concentration of inhibitors.

Assessment of the role of DNA repair in damaged forensic samples.

Previous studies on DNA damage and repair have involved in vitro laboratory procedures that induce a single type of lesion in naked templates. Although repair of singular, sequestered types of DNA damage has shown some success, forensic and ancient specimens likely contain a number of different types of lesions. This study sought to (1) develop protocols to damage DNA in its native state, (2) generate a pool of candidate samples for repair that more likely emulate authentic forensic samples, and (3) assess the ability of the PreCR(TM) Repair Mix to repair the resultant lesions. Complexed, native DNA is more difficult to damage than naked DNA. Modified procedures included the use of higher concentrations and longer exposure times. Three types of samples, those that demonstrated damage based on short tandem repeat (STR) profile signals, were selected for repair experiments: environmentally damaged bloodstains, bleach-damaged whole blood, and human skeletal remains. Results showed trends of improved performance of STR profiling of bleach-damaged DNA. However, the repair assay did not improve DNA profiles from environmentally damaged bloodstains or bone, and in some cases resulted in lower RFU values for STR alleles. The extensive spectrum of DNA damage and myriad combinations of lesions that can be present in forensic samples appears to pose a challenge for the in vitro PreCR(TM) assay. The data suggest that the use of PreCR in casework should be considered with caution due to the assay's varied results.

Autosomal and Y-STR analysis of degraded DNA from the 120-year-old skeletal remains of Ezekiel Harper.

The 120-year-old skeletal remains of Confederate Civil War soldier Captain Ezekiel "Zeke" Harper were exhumed by court order in January 2011 for DNA analysis. The goal of the DNA testing was to support or refute whether Captain Harper had fathered a son (Earl J. Maxwell) with his Native American maid prior to his murder in 1892. Bones with adequate structural integrity (left tibia, right tibia, right femur, mandible, four teeth) were retrieved from the burial site and sent to the Institute of Applied Genetics in Fort Worth, Texas for analysis. Given the age and condition of the remains, three different extraction methods were used to maximize the probability of DNA recovery. The majority of the DNA isolates from over fifty separate bone sections yielded partial autosomal STR genotypes and partial Y-STR haplotypes. After comparing the partial results for concordance, consensus profiles were generated for comparison to reference samples from alleged family members. Considering the genetic recombination that occurs in autosomal DNA over the generations within a family, Y-STR analysis was determined to be the most appropriate and informative approach for determining potential kinship. Two of Earl J. Maxwell's grandsons submitted buccal samples for comparison. The Y-STR haplotypes obtained from both of these reference samples were identical to each other and to the alleles in Ezekiel Harper's consensus profile at all 17 loci examined. This Y-STR haplotype was not found in either of two major Y-STR population databases (U.S. Y-STR database and YHRD). The fact that the Y-STR haplotype obtained from Ezekiel's skeletal remains and Earl's grandsons is not found in either population database demonstrates its rarity and further supports a paternal lineage relationship among them. Results of the genetic analyses are consistent with the hypothesis that Earl J. Maxwell is the son of Ezekiel Harper.

Genetics of plumage color in the Gyrfalcon (Falco rusticolus): analysis of the melanocortin-1 receptor gene.

Genetic variation at the melanocortin-1 receptor (MC1R) gene is correlated with melanin color variation in a few reported vertebrates. In Gyrfalcon (Falco rusticolus), plumage color variation exists throughout their arctic and subarctic circumpolar distribution, from white to gray and almost black. Multiple color variants do exist within the majority of populations; however, a few areas (e.g., northern Greenland and Iceland) possess a single color variant. Here, we show that the white/melanic color pattern observed in Gyrfalcons is explained by allelic variation at MC1R. Six nucleotide substitutions in MC1R resulted in 9 alleles that differed in geographic frequency with at least 2 MC1R alleles observed in almost all sampled populations in Greenland, Iceland, Canada, and Alaska. In north Greenland, where white Gyrfalcons predominate, a single MC1R allele was observed at high frequency (>98%), whereas in Iceland, where only gray Gyrfalcons are known to breed, 7 alleles were observed. Of the 6 nucleotide substitutions, 3 resulted in amino acid substitutions, one of which (Val(128)Ile) was perfectly associated with the white/melanic polymorphism. Furthermore, the degree of melanism was correlated with number of MC1R variant alleles, with silver Gyrfalcons all heterozygous and the majority of dark gray individuals homozygous (Ile(128)). These results provide strong support that MC1R is associated with plumage color in this species.