A systematic investigation of human DNA preservation in medieval skeletons

Identification of the 18 World War II executed citizens of Adele, Rethymnon, Crete using an ancient DNA approach and low coverage genomes

In the Battle of Crete during the World War II occupation of Greece, the German forces faced substantial civilian resistance. To retribute the numerous German losses, a series of mass executions took place in numerous places in Crete; a common practice reported from Greece and elsewhere. In Adele, a village in the regional unit of Rethymnon, 18 male civilians were executed and buried in a burial pit at the Sarakina site. In this study, the first one conducted for a conflict that occurred in Greece, we identified for humanitarian purposes the 18 skulls of the Sarakina victims, following a request from the local community of Adele. The molecular identification of historical human remains via ancient DNA approaches and low coverage whole genome sequencing has only recently been introduced. Here, we performed genome skimming on the living relatives of the victims, as well as high throughput historical DNA analysis on the skulls to infer the kinship degrees among the victims via genetic relatedness analyses. We also conducted targeted anthropological analysis to successfully complete the identification of all Sarakina victims. We demonstrate that our methodological approach constitutes a potentially highly informative forensic tool to identify war victims. It can hence be applied to analogous studies on degraded DNA, thus, paving the path for systematic war victim identification in Greece and beyond.

Advancing responsible genomic analyses of ancient mollusc shells

The analysis of the DNA entrapped in ancient shells of molluscs has the potential to shed light on the evolution and ecology of this very diverse phylum. Ancient genomics could help reconstruct the responses of molluscs to past climate change, pollution, and human subsistence practices at unprecedented temporal resolutions. Applications are however still in their infancy, partly due to our limited knowledge of DNA preservation in calcium carbonate shells and the need for optimized methods for responsible genomic data generation. To improve ancient shell genomic analyses, we applied high-throughput DNA sequencing to 27 Mytilus mussel shells dated to ~111-6500 years Before Present, and investigated the impact, on DNA recovery, of shell imaging, DNA extraction protocols and shell sub-sampling strategies. First, we detected no quantitative or qualitative deleterious effect of micro-computed tomography for recording shell 3D morphological information prior to sub-sampling. Then, we showed that double-digestion and bleach treatment of shell powder prior to silica-based DNA extraction improves shell DNA recovery, also suggesting that DNA is protected in preservation niches within ancient shells. Finally, all layers that compose Mytilus shells, i.e., the nacreous (aragonite) and prismatic (calcite) carbonate layers, with or without the outer organic layer (periostracum) proved to be valuable DNA reservoirs, with aragonite appearing as the best substrate for genomic analyses. Our work contributes to the understanding of long-term molecular preservation in biominerals and we anticipate that resulting recommendations will be helpful for future efficient and responsible genomic analyses of ancient mollusc shells.

No Bones About It: Sex Is Binary

Anthropologists have led the way in formulating techniques that reveal skeletal differences between males and females. Understanding of physical differences in the pelvis related to childbirth, hormonal impacts on bones, and extensive comparative studies have provided anthropologists with an array of traits and measurements that help them estimate sex using just bones. Forensic anthropologists and bioarcheologists are improving their ability to differentiate males and females by increasing research on a variety of postcranial bones and through the use of molecular data, especially new methods called proteomics, to identify sex in prepubescent juveniles. As remains from more cultures and time periods are studied, sex identification will continue to improve, because skeletal sex differences are in large part biologically determined. Yet, anthropologists have also been at the forefront of arguing that sex lies on a spectrum. Anthropologists who view sex as on a spectrum may deter sex identification progress; from their perspective, an individual of an undetermined sex may just be a nonbinary individual. Anthropologists who consider sex is on a spectrum are coming to this conclusion in part because they are looking for anatomical ideals, mistaking pathology for variation, and confusing independent variables with dependent variables. Nonetheless, anthropologists need to continue to improve sex identification techniques to reconstruct the past accurately, which may reveal less strict sex roles than previously presumed and help with the identification of crime victims. Forensic anthropologists should also increase their efforts to identify whether individuals have undergone medical procedures intended to change one's gender due to the current rise in transitioning individuals.

An optimal skeletal element for DNA testing: Evaluation of DNA quantity and quality from various bone types in routine forensic practice

For human identification, the quality and quantity of DNA must be sufficient for amplification and analysis. When DNA extraction from bone tissues and teeth is required, the optimal skeletal elements should be selected as samples for DNA extraction because DNA yield differs among elements. Recently, some studies have reported that a high quantity of high-quality DNA can be extracted from the small cancellous bones of the hands and feet. In this study, we evaluated the effectiveness of small cancellous bones in the human identification of skeletal remains in routine forensic genetic casework. Cancellous bones [phalanges, (meta)carpal bones, and (meta)tarsal bones)] and the cortical bones (femur and petrous bones) and teeth, which have generally been recommended as samples, were collected from the same individuals that needed identifying using DNA analysis in our laboratory. The quantity of DNA from small cancellous bones tended to be higher than that from cortical bones, and the quality from the former was as high as that from the latter. This study showed that in routine forensic casework, the small cancellous bones of the hands and feet should be actively selected as samples for DNA testing.

A fresh perspective on infrared spectroscopy as a prescreening method for molecular and stable isotopes analyses on ancient human bones

Following the development of modern genome sequencing technologies, the investigation of museum osteological finds is increasingly informative and popular. Viable protocols to help preserve these collections from exceedingly invasive analyses, would allow greater access to the specimens for scientific research. The main aim of this work is to survey skeletal tissues, specifically petrous bones and roots of teeth, using infrared spectroscopy as a prescreening method to assess the bone quality for molecular analyses. This approach could overcome the major problem of identifying useful genetic material in archaeological bone collections without resorting to demanding, time consuming and expensive laboratory studies. A minimally invasive sampling of archaeological bones was developed and bone structural and compositional changes were examined, linking isotopic and genetic data to infrared spectra. The predictive model based on Infrared parameters is effective in determining the occurrence of ancient DNA (aDNA); however, the quality/quantity of aDNA cannot be determined because of the influence of environmental and local factors experienced by the examined bones during the burial period.

Assessing the usefulness of Raman spectroscopy and lipid analysis of decomposed human bones in forensic genetics and molecular taphonomy

Bones are among the structures most likely to be recovered after death. However, the low quantity of preserved DNA and complex processing from sample to DNA profile make forensic DNA analysis of bones a challenging task. Raman spectroscopy and gas chromatography-mass spectrometry (GC/MS), have the potential to be useful as screening tools for DNA analysis and in decomposition studies. The objective of this research was to assess the usefulness of such molecular investigations. Femur samples collected from 50 decomposing human bodies were subjected to Raman spectroscopy and GC/MS. Assessment of nuclear DNA quantity and short tandem repeat (STR) genotyping efficiency were also performed. Raman parameters (crystallinity, carbonate-to-phosphate ratio, mineral-to-matrix ratio) and detected lipids were recorded. Background fluorescence proved problematic for Raman analysis of forensic bones. Regardless, it was not associated with less preserved DNA or less detected STR alleles. Fatty acids, hydrocarbons, and five types of fatty acid methyl esters (FAMEs) were detected. The main phosphate peak position in Raman spectra was significantly correlated with preserved DNA (p = 0.03713), while significantly more STR alleles were detected in bones containing methyl hexadecenoate (p = 0.04236). Detection of FAMEs in the bone matrix suggests a reaction between methanol produced by bacteria and free fatty acids, which are not associated with the level of preservation of endogenous DNA. The techniques assessed have shown to be useful in molecular taphonomy studies and forensic genetics.

Comparative analysis of DNA preservation in permanent and deciduous teeth of adults and non-adults: Implications for archaeological and forensic research

This study investigates the preservation of DNA in different categories of teeth, including permanent and deciduous, fully developed and not fully developed, in both adults and non-adults. Teeth were sampled from a modern-era cemetery in Ljubljana, Slovenia. DNA extraction was performed using a full demineralisation protocol. DNA quantity and quality were assessed using qPCR analyses, and autosomal STR typing was conducted to verify genetic profiles. Results revealed significant differences in DNA preservation among various tooth categories. Fully developed permanent teeth of adults exhibited the highest DNA yields, attributed to their fully developed roots and thicker cementum, which is rich in DNA. Deciduous teeth, with thinner enamel and cementum, showed lower DNA preservation regardless of developmental stage. Non-adult teeth generally yielded less DNA compared to adults, even when considering only fully developed permanent teeth, indicating factors beyond developmental stage. These findings suggest that, in archaeological and forensic contexts, researchers should prioritize fully developed permanent teeth for DNA analysis due to their superior preservation. Additionally, this study underscores the importance of considering tooth type and developmental stage when selecting samples for genetic analysis in cases where petrous bone is unavailable, expanding our understanding of DNA preservation in human remains.

Hit or miss - A metagenomic evaluation of intra-bone variability of host pathogen load in tuberculosis-infected human remains

Many sampling protocols have been established to successfully retrieve human DNA from archaeological remains, however the systematic detection of ancient pathogens remains challenging. Here, we present a first assessment of the intra-bone variability of metagenomic composition in human skeletal remains and its effect on the sampling success for Mycobacterium tuberculosis (MTB) and human endogenous DNA. For this purpose, four bone samples from published peer-reviewed studies with PCR-based evidence for ancient MTB DNA were selected. Two bone samples of a Neolithic individual from Halberstadt, Germany and two ribs of two 18th-century Hungarian church mummies were sampled at multiple locations for equal amounts, followed by DNA extraction and library construction. Shotgun sequencing data was generated for taxonomic profiling as well as quantitative and qualitative evaluation of MTB and human endogenous DNA. Despite low variance in microbial diversity within and across samples, intra-bone variability of up to 36.45- and 62.88-fold for authentic ancient MTB and human reads, respectively, was detected. This study demonstrates the variable sampling success for MTB and human endogenous DNA within single skeletal samples despite relatively consistent microbial composition and highlights how a multisampling approach can facilitate the detection of hotspots with highly concentrated pathogen and human endogenous DNA.

Genetic sexing of subadult skeletal remains

When subadult skeletons need to be identified, biological sex diagnosis is one of the first steps in the identification process. Sex assessment of subadults using morphological features is unreliable, and molecular genetic methods were applied in this study. Eighty-three ancient skeletons were used as models for poorly preserved DNA. Three sex-informative markers on the Y and X chromosome were used for sex identification: a qPCR test using the PowerQuant Y target included in PowerQuant System (Promega), the amelogenin test included in ESI 17 Fast STR kit (Promega), and a Y-STR amplification test using the PowerPlex Y-23 kit (Promega). Sex was successfully determined in all but five skeletons. Successful PowerQuant Y-target, Y-amelogenin, and Y-chromosomal STR amplifications proved the presence of male DNA in 35 skeletons, and in 43 subadults female sex was established. No match was found between the genetic profiles of subadult skeletons, and the elimination database and negative control samples produced no profiles, indicating no contamination issue. Our study shows that genetic sex identification is a very successful approach for biological sexing of subadult skeletons whose sex cannot be assessed by anthropological methods. The results of this study are applicable for badly preserved subadult skeletons from routine forensic casework.

Biological and substitute parents in Beaker period adult-child graves

Joint inhumations of adults and children are an intriguing aspect of the shift from collective to single burial rites in third millennium BC Western Eurasia. Here, we revisit two exceptional Beaker period adult-child graves using ancient DNA: Altwies in Luxembourg and Dunstable Downs in Britain. Ancestry modelling and patterns of shared IBD segments between the individuals examined, and contemporary genomes from Central and Northwest Europe, highlight the continental connections of British Beakers. Although simultaneous burials may involve individuals with no social or biological ties, we present evidence that close blood relations played a role in shaping third millennium BC social systems and burial practices, for example a biological mother and her son buried together at Altwies. Extended family, such as a paternal aunt at Dunstable Downs, could also act as 'substitute parents' in the grave. Hypotheses are explored to explain such simultaneous inhumations. Whilst intercommunity violence, infectious disease and epidemics may be considered as explanations, they fail to account for both the specific, codified nature of this particular form of inhumation, and its pervasiveness, as evidenced by a representative sample of 131 adult-child graves from 88 sites across Eurasia, all dating to the third and second millennia BC.

A comparison between petrous bone and tooth, femur and tibia DNA analysis from degraded skeletal remains

Skeletal remains are the only biological material that remains after long periods; however, environmental conditions such as temperature, humidity, and pH affect DNA preservation, turning skeletal remains into a challenging sample for DNA laboratories. Sample selection is a key factor, and femur and tooth have been traditionally recommended as the best substrate of genetic material. Recently, petrous bone (cochlear area) has been suggested as a better option due to its DNA yield. This research aims to evaluate the efficiency of petrous bone compared to other cranium samples (tooth) and postcranial long bones (femur and tibia). A total amount of 88 samples were selected from 38 different individuals. The samples were extracted by using an organic extraction protocol, DNA quantification by Quantifiler Trio kit and amplified with GlobalFiler kit. Results show that petrous bone outperforms other bone remains in quantification data, yielding 15-30 times more DNA than the others. DNA profile data presented likeness between petrous bone and tooth regarding detected alleles; however, the amount of DNA extracted in petrous bones allowed us to obtain more informative DNA profiles with superior quality. In conclusion, petrous bone or teeth sampling is recommended if DNA typing is going to be performed with environmentally degraded skeletal remains.

Eye and hair color prediction of an early medieval adult and subadult skeleton using massive parallel sequencing technology

Phenotypic trait prediction in ancient DNA analysis can provide information about the external appearance of individuals from past human populations. Some studies predicting eye and hair color in ancient adult skeletons have been published, but not for ancient subadult skeletons, which are more prone to decay. In this study, eye and hair color were predicted for an early medieval adult skeleton and a subadult skeleton that was anthropologically characterized as a middle-aged man and a subadult of unknown sex about 6 years old. When processing the petrous bones, precautions were taken to prevent contamination with modern DNA. The MillMix tissue homogenizer was used for grinding, 0.5 g of bone powder was decalcified, and DNA was purified in Biorobot EZ1. The PowerQuant System was used for quantification and a customized version of the HIrisPlex panel for massive parallel sequencing (MPS) analysis. Library preparation and templating were performed on the HID Ion Chef Instrument and sequencing on the Ion GeneStudio S5 System. Up to 21 ng DNA/g of powder was obtained from ancient petrous bones. Clean negative controls and no matches with elimination database profiles confirmed no contamination issue. Brown eyes and dark brown or black hair were predicted for the adult skeleton and blue eyes and brown or dark brown hair for the subadult skeleton. The MPS analysis results obtained proved that it is possible to predict hair and eye color not only for an adult from the Early Middle Ages, but also for a subadult skeleton dating to this period.

14th century Yersinia pestis genomes support emergence of pestis secunda within Europe

Pestis secunda (1356-1366 CE) is the first of a series of plague outbreaks in Europe that followed the Black Death (1346-1353 CE). Collectively this period is called the Second Pandemic. From a genomic perspective, the majority of post-Black Death strains of Yersinia pestis thus far identified in Europe display diversity accumulated over a period of centuries that form a terminal sub-branch of the Y. pestis phylogeny. It has been debated if these strains arose from local evolution of Y. pestis or if the disease was repeatedly reintroduced from an external source. Plague lineages descended from the pestis secunda, however, are thought to have persisted in non-human reservoirs outside Europe, where they eventually gave rise to the Third Pandemic (19th and 20th centuries). Resolution of competing hypotheses on the origins of the many post-Black Death outbreaks has been hindered in part by the low representation of Y. pestis genomes in archaeological specimens, especially for the pestis secunda. Here we report on five individuals from Germany that were infected with lineages of plague associated with the pestis secunda. For the two genomes of high coverage, one groups within the known diversity of genotypes associated with the pestis secunda, while the second carries an ancestral genotype that places it earlier. Through consideration of historical sources that explore first documentation of the pandemic in today's Central Germany, we argue that these data provide robust evidence to support a post-Black Death evolution of the pathogen within Europe rather than a re-introduction from outside. Additionally, we demonstrate retrievability of Y. pestis DNA in post-cranial remains and highlight the importance of hypothesis-free pathogen screening approaches in evaluations of archaeological samples.

Improving kinship probability in analysis of ancient skeletons using identity SNPs and MPS technology

In forensic kinship analysis and human identification cases, analysis of STRs is the gold standard. When badly preserved ancient DNA is used for kinship analysis, short identity SNPs are more promising for successful amplification. In this work, kinship analysis was performed on two skeletons from the Early Middle Ages. The surface contaminants of petrous bones were removed by chemical cleaning and UV irradiation; DNA was isolated through full demineralization and purified in an EZ1 Advanced XL machine. The PowerQuant kit was used to analyze DNA yield and degradation, and on average, 17 ng DNA/g of petrous bone was obtained. Both skeletons were typed in duplicate for STR markers using the Investigator EssplexPlus SE QS kit, and comparison of partial consensus genotypes showed shared allelic variants at most loci amplified, indicating close kinship. After statistical calculation, the full-sibling kinship probability was too low for kinship confirmation, and additional analyses were performed with PCR-MPS using the Precision ID Identity Panel. The HID Ion Chef Instrument was used to prepare the libraries and for templating and the Ion GeneStudio S5 System for sequencing. Analysis of identity SNPs produced full genetic profiles from both skeletons. For combined likelihood ratio (LR) calculation, the product rule was used, combining LR for STRs and LR for SNPs, and a combined LR of 3.3 × 10⁷ (corresponding to a full-sibling probability of 99.999997%) was calculated. Through the SNP PCR-MPS that followed the STR analysis, full-sibling kinship between the ancient skeletons excavated from an early medieval grave was confirmed.

Kinship analysis of 5th- to 6th-century skeletons of Romanized indigenous people from the Bled-Pristava archaeological site

The familial relationship between skeletons buried together in a shared grave is important for understanding the burial practices of past human populations. Four skeletons were excavated from the Late Antiquity part of the Bled-Pristava burial site in Slovenia, dated to the 5th to 6th century. They were anthropologically characterized as two adults (a middle-aged man and a young woman) and two non-adults (of unknown sex). Based on stratigraphy, the skeletons were considered to be buried simultaneously in one grave. Our aim was to determine whether the skeletons were related. Petrous bones and teeth were used for genetic analysis. Specific precautions were followed to prevent contamination of ancient DNA with contemporary DNA, and an elimination database was established. Bone powder was obtained using a MillMix tissue homogenizer. Prior to extracting the DNA using Biorobot EZ1, 0.5 g of powder was decalcified. The PowerQuant System was used for quantification, various autosomal kits for autosomal short tandem repeat (STR) typing, and the PowerPlex Y23 kit for Y-STR typing. All analyses were performed in duplicate. Up to 28 ng DNA/g of powder was extracted from the samples analyzed. Almost full autosomal STR profiles obtained from all four skeletons and almost full Y-STR haplotypes obtained from two male skeletons were compared, and the possibility of a familial relationship was evaluated. No amplification was obtained in the negative controls, and no match was found in the elimination database. Autosomal STR statistical calculations confirmed that the adult male was the father of two non-adult individuals and one young adult individual from the grave. The relationship between the males (father and son) was additionally confirmed by an identical Y-STR haplotype that belonged to the E1b1b haplogroup, and a combined likelihood ratio for autosomal and Y-STRs was calculated. Kinship analysis confirmed with high confidence (kinship probability greater than 99.9% was calculated for all three children) that all four skeletons belonged to the same family (a father, two daughters, and a son). Through genetic analysis, the burial of members of the same family in a shared grave was confirmed as a burial practice of the population living in the Bled area in Late Antiquity.

Human Archaeological Dentin as Source of Polar and Less Polar Metabolites for Untargeted Metabolomic Research: The Case of Yersinia pestis

Metabolomic approaches, such as in clinical applications of living individuals, have shown potential use for solving questions regarding the past when applied to archaeological material. Here, we study for the first time the potential of this Omic approach as applied to metabolites extracted from archaeological human dentin. Dentin obtained from micro sampling the dental pulp of teeth of victims and non-victims of Yersinia pestis (plague) from a 6th century Cambridgeshire site are used to evaluate the potential use of such unique material for untargeted metabolomic studies on disease state through liquid chromatography hyphenated to high-resolution mass spectrometry (LC-HRMS). Results show that small molecules of both likely endogenous and exogenous sources are preserved for a range of polar and less polar/apolar metabolites in archaeological dentin; however, untargeted metabolomic profiles show no clear differentiation between healthy and infected individuals in the small sample analysed (n = 20). This study discusses the potential of dentin as a source of small molecules for metabolomic assays and highlights: (1) the need for follow up research to optimise sampling protocols, (2) the requirements of studies with larger sample numbers and (3) the necessity of more databases to amplify the positive results achievable with this Omic technique in the archaeological sciences.

A 23,000-year-old southern Iberian individual links human groups that lived in Western Europe before and after the Last Glacial Maximum

Human populations underwent range contractions during the Last Glacial Maximum (LGM) which had lasting and dramatic effects on their genetic variation. The genetic ancestry of individuals associated with the post-LGM Magdalenian technocomplex has been interpreted as being derived from groups associated with the pre-LGM Aurignacian. However, both these ancestries differ from that of central European individuals associated with the chronologically intermediate Gravettian. Thus, the genomic transition from pre- to post-LGM remains unclear also in western Europe, where we lack genomic data associated with the intermediate Solutrean, which spans the height of the LGM. Here we present genome-wide data from sites in Andalusia in southern Spain, including from a Solutrean-associated individual from Cueva del Malalmuerzo, directly dated to ~23,000 cal yr BP. The Malalmuerzo individual carried genetic ancestry that directly connects earlier Aurignacian-associated individuals with post-LGM Magdalenian-associated ancestry in western Europe. This scenario differs from Italy, where individuals associated with the transition from pre- and post-LGM carry different genetic ancestries. This suggests different dynamics in the proposed southern refugia of Ice Age Europe and posits Iberia as a potential refugium for western European pre-LGM ancestry. More, individuals from Cueva Ardales, which were thought to be of Palaeolithic origin, date younger than expected and, together with individuals from the Andalusian sites Caserones and Aguilillas, fall within the genetic variation of the Neolithic, Chalcolithic and Bronze Age individuals from southern Iberia.

Examination of human osteoarchaeological remains as a feasible source of polar and apolar metabolites to study past conditions

Metabolomics is a modern tool that aids in our understanding of the molecular changes in organisms. Archaeological science is a branch of archaeology that explores different archaeological materials using modern analytical tools. Human osteoarchaeological material are a frequent finding in archaeological contexts and have the potential to offer information about previous human populations, which can be illuminating about our current condition. Using a set of samples comprising different skeletal elements and bone structures, here we explore for the first time the possibility of extracting metabolites from osteoarchaeological material. Here, a protocol for extraction and measurement of extracted polar and less-polar/apolar metabolites by ultra-high performance liquid chromatography hyphenated to high resolution mass spectrometry is presented to measure the molecules separated after a reversed phase and hydrophilic interaction liquid chromatography column. Molecular information was obtained, showing that osteoarchaeological material is a viable source of molecular information for metabolomic studies.

Sex bias in Neolithic megalithic burials

Objectives

A statistical study comparing osteological and ancient DNA determinations of sex was conducted in order to investigate whether there are sex biases in United Kingdom and Irish Neolithic megalithic burials.

Materials and Methods

Genetic and osteological information from human individuals from 32 megalithic sites in the UK and Ireland dating from 4000 to 2500 cal. BCE was collected and statistically analyzed to test whether there is a true over‐representation of males at these sites. The published dataset from the study by Sánchez‐Quinto et al. in 2019 was initially analyzed before being refined and included in a larger dataset. Osteological analysis of sex bias was limited to adults with available sex estimations, and genetic analysis limited to published data

Results

Two sites consistently returned significant p ‐values suggesting a potential over‐representation in osteological males at one site (Knowe of Midhowe, Orkney) and genetic males in the other (Primrose Grange, Ireland). Cumulative statistical analyses point towards a male bias in the representation of sexes in Neolithic megalithic burials, but these results do not reflect the site‐by‐site and regional variation found in this study.

Discussion

The interpretation of sex bias, that is, the over‐representation of one sex over another ‐ depends on other socio‐cultural variables (e.g., kinship) and the emphasis placed on statistical significance. The trend towards males being over‐represented in Neolithic megalithic burials is not as clear as previously thought, and requires further testing and data collection to uncover.

Examining pathogen DNA recovery across the remains of a 14th century Italian friar (Blessed Sante) infected with Brucella melitensis

OBJECTIVE

To investigate variation in ancient DNA recovery of Brucella melitensis, the causative agent of brucellosis, from multiple tissues belonging to one individual MATERIALS: 14 samples were analyzed from the mummified remains of the Blessed Sante, a 14 ^th century Franciscan friar from central Italy, with macroscopic diagnosis of probable brucellosis.

METHODS

Shotgun sequencing data from was examined to determine the presence of Brucella DNA.

RESULTS

Three of the 14 samples contained authentic ancient DNA, identified as belonging to B. melitensis. A genome (23.81X depth coverage, 0.98 breadth coverage) was recovered from a kidney stone. Nine of the samples contained reads classified as B. melitensis (7-169), but for many the data quality was insufficient to withstand our identification and authentication criteria.

CONCLUSIONS

We identified significant variation in the preservation and abundance of B. melitensis DNA present across multiple tissues, with calcified nodules yielding the highest number of authenticated reads. This shows how greatly sample selection can impact pathogen identification.

SIGNIFICANCE

Our results demonstrate variation in the preservation and recovery of pathogen DNA across tissues. This study highlights the importance of sample selection in the reconstruction of infectious disease burden and highlights the importance of a holistic approach to identifying disease.

LIMITATIONS

Study focuses on pathogen recovery in a single individual.

SUGGESTIONS FOR FURTHER RESEARCH

Further analysis of how sampling impacts aDNA recovery will improve pathogen aDNA recovery and advance our understanding of disease in past peoples.

Comparison of DNA preservation between adult and non-adult ancient skeletons

Studies evaluating DNA preservation in non-adults, or comparing preservation in adults and non-adults, are very rare. This study compares the preservation of DNA in the skeletal remains of adults and non-adults. It compares the quality and quantity of DNA recovered from different skeletal elements of adults and non-adults, and from non-adults of different age classes. In addition, the preservation of DNA in males and females is compared. Bone DNA preservation was estimated by measuring nuclear DNA concentration and its degradation, and through STR typing success. The study analyzed 29 adult skeletons and 23 non-adult skeletons from the Ljubljana-Polje archeological site, dating from the seventeenth to nineteenth century, and up to four skeletal elements (petrous bone, femur, calcaneus, and talus) were included. After full demineralization extraction, the PowerQuant System and the PowerPlex ESI 17 Fast System (Promega) were used for qPCR and STR typing, respectively. The results showed that, among the four bone types analyzed, only the petrous bone proved to be a suitable source of DNA for STR typing of non-adult skeletal remains, and DNA yield is even higher than in the adult petrous bone, which can be attributed to the higher DNA degradation observed in the adult petrous bone. In adult skeletons, petrous bones and tali produced high STR amplification success and low DNA yield was observed in adult femurs. The results of this study are applicable for the sampling strategy in routine forensic genetics cases for solving identification cases, including badly preserved non-adult and also adult skeletons.

Ethics of DNA research on human remains: five globally applicable guidelines

We are a group of archaeologists, anthropologists, curators and geneticists representing diverse global communities and 31 countries. All of us met in a virtual workshop dedicated to ethics in ancient DNA research held in November 2020. There was widespread agreement that globally applicable ethical guidelines are needed, but that recent recommendations grounded in discussion about research on human remains from North America are not always generalizable worldwide. Here we propose the following globally applicable guidelines, taking into consideration diverse contexts. These hold that: (1) researchers must ensure that all regulations were followed in the places where they work and from which the human remains derived; (2) researchers must prepare a detailed plan prior to beginning any study; (3) researchers must minimize damage to human remains; (4) researchers must ensure that data are made available following publication to allow critical re-examination of scientific findings; and (5) researchers must engage with other stakeholders from the beginning of a study and ensure respect and sensitivity to stakeholder perspectives. We commit to adhering to these guidelines and expect they will promote a high ethical standard in DNA research on human remains going forward.

Whole-exome sequencing of the mummified remains of Cangrande della Scala (1291-1329 CE) indicates the first known case of late-onset Pompe disease

Mummified remains of relevant historical figures are nowadays an important source of information to retrace data concerning their private life and health, especially when historical archives are not available. Next-generation-sequencing was proved to be a valuable tool to unravel the characteristics of these individuals through their genetic heritage. Using the strictest criteria currently available for the validation of ancient DNA sequences, whole-genome and whole-exome sequencing were generated from the mummy remains of an Italian nobleman died almost 700 years ago, Cangrande della Scala. While its genome sequencing could not yield sufficient coverage for in depth investigation, exome sequencing could overcome the limitations of this approach to achieve significantly high coverage on coding regions, thus allowing to perform the first extensive exome analysis of a mummy genome. Similar to a standard "clinical exome analysis" conducted on modern DNA, an in-depth variant annotation, high-quality filtering and interpretation was performed, leading to the identification of a genotype associated with late-onset Pompe disease (glycogen storage disease type II). This genetic diagnosis was concordant with the limited clinical history available for Cangrande della Scala, who likely represents the earliest known case of this autosomal recessive metabolic disorder.

Twenty-Seven Y-Chromosome Short Tandem Repeats Analysis of Italian Mummies of the 16th and 18th Centuries: An Interdisciplinary Research

Roccapelago (MO) is a small village located in the Northern Central Apennines, with a population of 31 inhabitants (2014). In 2010, more than 400 individuals dated between the end of the 16th and the 18th century, many of which partially mummified, were discovered in the crypt of the church. This small village, because of its geographical location and surrounding environment, seems to possess the characteristics of a genetic isolate, useful for population genetics and genealogical analyses. Thus, a diachronic study of DNA aimed at investigating the structure and dynamics of the population of Roccapelago over the about 4 centuries, was conducted by analyzing ancient and modern inhabitants of the village. The 14 modern samples were selected by considering both the founder surnames of the village, identified thanks to the study of parish registers, and the grandparent's criterion. From 25 ancient mummies, morphologically assigned to male individuals, the petrous bone, that harbors high DNA amounts, was selected for the DNA extraction. The quantification and qualitative assessment of total human male DNA were evaluated by a real-time PCR assay using the Quantifiler Trio DNA Quantification Kit and multiplex PCR of 27 Y-chromosome short tandem repeat (Y-STR) markers included in the Yfiler Plus PCR Amplification Kit, with seven rapidly mutating Y-STR loci for improving discrimination of male lineages, was performed to genotype the samples. Y-STRs were analyzed according to the criteria of ancient DNA (aDNA) analysis to ensure that authentic DNA typing results were obtained from these ancient samples. The molecular analysis showed the usefulness of the Y chromosome to identify historically relevant remains and discover patterns of relatedness in communities moving from anthropology to genetic genealogy and forensics.

Ten millennia of hepatitis B virus evolution

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Human mobility at Tell Atchana (Alalakh), Hatay, Turkey during the 2nd millennium BC: Integration of isotopic and genomic evidence

The Middle and Late Bronze Age, a period roughly spanning the 2^nd millennium BC (ca. 2000–1200 BC) in the Near East, is frequently referred to as the first ‘international age’, characterized by intense and far-reaching contacts between different entities from the eastern Mediterranean to the Near East and beyond. In a large-scale tandem study of stable isotopes and ancient DNA of individuals excavated at Tell Atchana (Alalakh, located in Hatay, Turkey), we explored the role of mobility at the capital of a regional kingdom, named Mukish during the Late Bronze Age, which spanned the Amuq Valley and some areas beyond. We generated strontium and oxygen isotope data from dental enamel for 53 individuals and 77 individuals, respectively, and added ancient DNA data of 10 newly sequenced individuals to a dataset of 27 individuals published in 2020. Additionally, we improved the DNA coverage of one individual from this 2020 dataset. The DNA data revealed a very homogeneous gene pool. This picture of an overwhelmingly local ancestry was consistent with the evidence of local upbringing in most of the individuals indicated by the isotopic data, where only five were found to be non-local. High levels of contact, trade, and exchange of ideas and goods in the Middle and Late Bronze Ages, therefore, seem not to have translated into high levels of individual mobility detectable at Tell Atchana.

A method for the temperature-controlled extraction of DNA from ancient bones

Contamination with microbial and other exogenous DNA poses a significant challenge in the generation of genome-wide sequence data from ancient skeletal remains. Here we describe a method for separating ancient DNA into multiple fractions during DNA extraction by sequential temperature-controlled release of DNA into sodium phosphate buffer. An evaluation of the effectiveness of the method using a set of three ancient bones resulted in between 1.6- and 32-fold enrichment of endogenous DNA compared with regular DNA extraction. For two bones, the method outperformed previous methods of decontaminating ancient bones, including hypochlorite treatment, which resulted in near-complete destruction of DNA in the worst-preserved sample. This extraction method expands the spectrum of methods available for depleting contaminant DNA from ancient skeletal remains.

Progress in forensic bone DNA analysis: Lessons learned from ancient DNA

Research on ancient and forensic DNA is related in many ways, and the two fields must deal with similar obstacles. Therefore, communication between these two communities has the potential to improve results in both research fields. Here, we present the insights gained in the ancient DNA community with regard to analyzing DNA from aged skeletal material and the potential use of the developed protocols in forensic work. We discuss the various steps, from choosing samples for DNA extraction to deciding between classical PCR amplification and massively parallel sequencing approaches. Based on the progress made in ancient DNA analyses combined with the requirements of forensic work, we suggest that there is substantial potential for incorporating ancient DNA approaches into forensic protocols, a process that has already begun to a considerable extent. However, taking full advantage of the experiences gained from ancient DNA work will require comparative studies by the forensic DNA community to tailor the methods developed for ancient samples to the specific needs of forensic studies and case work. If successful, in our view, the benefits for both communities would be considerable.

Predicting sample success for large-scale ancient DNA studies on marine mammals

In recent years, nonhuman ancient DNA studies have begun to focus on larger sample sizes and whole genomes, offering the potential to reveal exciting and hitherto unknown answers to ongoing biological and archaeological questions. However, one major limitation to such studies is the substantial financial and time investments still required during sample screening, due to uncertainty regarding successful sample selection. This study investigates the effect of a wide range of sample properties including latitude, sample age, skeletal element, collagen preservation, and context on endogenous content and DNA damage profiles for 317 ancient and historic pinniped samples collected from across the North Atlantic and surrounding regions. Using generalised linear and mixed-effect models, we found that a range of factors affected DNA preservation within each of the species under consideration. The most important findings were that endogenous content varied significantly within species according to context, the type of skeletal element, the collagen content and collection year. There also appears to be an effect of the sample's geographic origin, with samples from the Arctic generally showing higher endogenous content and lower damage rates. Both latitude and sample age were found to have significant relationships with damage levels, but only for walrus samples. Sex, ontogenetic age and extraction material preparation were not found to have any significant relationship with DNA preservation. Overall, skeletal element and sample context were found to be the most influential factors and should therefore be considered when selecting samples for large-scale ancient genome studies.

A minimally destructive protocol for DNA extraction from ancient teeth

Ancient DNA sampling methods-although optimized for efficient DNA extraction-are destructive, relying on drilling or cutting and powdering (parts of) bones and teeth. As the field of ancient DNA has grown, so have concerns about the impact of destructive sampling of the skeletal remains from which ancient DNA is obtained. Due to a particularly high concentration of endogenous DNA, the cementum of tooth roots is often targeted for ancient DNA sampling, but destructive sampling methods of the cementum often result in the loss of at least one entire root. Here, we present a minimally destructive method for extracting ancient DNA from dental cementum present on the surface of tooth roots. This method does not require destructive drilling or grinding, and, following extraction, the tooth remains safe to handle and suitable for most morphological studies, as well as other biochemical studies, such as radiocarbon dating. We extracted and sequenced ancient DNA from 30 teeth (and nine corresponding petrous bones) using this minimally destructive extraction method in addition to a typical tooth sampling method. We find that the minimally destructive method can provide ancient DNA that is of comparable quality to extracts produced from teeth that have undergone destructive sampling processes. Further, we find that a rigorous cleaning of the tooth surface combining diluted bleach and UV light irradiation seems sufficient to minimize external contaminants usually removed through the physical removal of a superficial layer when sampling through regular powdering methods.