Ancient DNA Research Articles

Subgenome-aware analyses reveal the genomic consequences of ancient allopolyploid hybridizations throughout the cotton family

Malvaceae comprise some 4,225 species in 243 genera and nine subfamilies and include economically important species, such as cacao, cotton, durian, and jute, with cotton an important model system for studying the domestication of polyploids. Here, we use chromosome-level genome assemblies from representatives of five or six subfamilies (depending on the placement of Ochroma) to differentiate coexisting subgenomes and their evolution during the family's deep history. The results reveal that the allohexaploid Helicteroideae partially derive from an allotetraploid Sterculioideae and also form a component of the allodecaploid Bombacoideae and Malvoideae. The ancestral Malvaceae karyotype consists of 11 protochromosomes. Four subfamilies share a unique reciprocal chromosome translocation, and two other subfamilies share a chromosome fusion. DNA alignments of single-copy nuclear genes do not yield the same relationships as inferred from chromosome structural traits, probably because of genes originating from different ancestral subgenomes. These results illustrate how chromosome-structural data can unravel the evolutionary history of groups with ancient hybrid genomes.

Holme I (Seahenge) and Holme II: ritual responses to climate change in Early Bronze Age Britain

Holme I and II were contemporary, adjacent Early Bronze Age (EBA) oak-timber enclosures exposed intertidally at Holme-next-the-sea, Norfolk, England, in 1998. Holme I enclosed a central upturned tree-stump, its function and intent unknown. Holme II is thought a mortuary structure. Both are proposed here best explained as independent ritual responses to reverse a period of severe climate deterioration recorded before 2049 BC when their timbers were felled. Holme I is thought erected on the summer-solstice, when the cuckoo traditionally stopped singing, departing to the ‘Otherworld’. It replicated the cuckoo’s supposed overwintering quarters: a tree-hole or the ‘bowers of the Otherworld’ represented by the tree-stump, remembered in folklore as ‘penning-the-cuckoo’ where a cuckoo is confined to keep singing and maintain summer. The cuckoo symbolised male-fertility being associated with several Indo-European goddesses of fertility that deified Venus - one previously identified in EBA Britain. Some mortal consorts of these goddesses appear to have been ritually sacrificed at Samhain. Holme II may be an enclosure for the body of one such ‘sacral king’. These hypotheses are considered, using abductive reasoning, as ‘inferences to the best explanations’ from the available evidence. They are supported with environmental data, astronomic and biological evidence, regional folklore, toponymy, and an ethnographic analogy with indigenous Late Iron Age practices that indirect evidence indicates were undertaken in EBA Britain. Cultural and religious continuity is supported by textual sources, the material record and ancient DNA (aDNA) studies.

Patagonian partnerships: the extinct Dusicyon avus and its interaction with prehistoric human communities.

The southern Mendoza province, located in the northern region of Patagonia, was inhabited by hunter-gatherer groups until historic times. Previous archaeological studies have reported canid remains among faunal assemblages, which were assumed to be part of the human diet. However, the taxonomic identification and significance of these canids within human groups have raised questions. In this study, we used ancient DNA analysis, morphological examination and stable isotope analysis (δ13Ccol and δ15N) to re-evaluate the taxonomic assignment of a canid discovered at the Late Holocene burial site of Cañada Seca. Previous morphological identifications suggested that it belonged to the genus Lycalopex, but our results conclusively demonstrate that the individual belongs to the extinct fox species Dusicyon avus. This finding expands Dusicyon avus' known geographical distribution to Patagonia's northern extremity. Furthermore, statistical predictions based on genetic divergence undermine the hypothesis that hybridization between Canis and Dusicyon, facilitated by the introduction of domestic dogs, played a role in the extinction of Dusicyon species. On the other hand, our findings indicate that a Dusicyon avus individual shared a similar diet and was probably buried alongside humans, suggesting a close relationship between the two species during their lives and deaths.

HERV-E ƛ 4-1 activation in peripheral blood mononuclear cells of the recurrent depression patients under the influence of human recombinant IL-1β

IntroductionMental disorders represent complex phenotypes and are the leading causes of global disease burden. Human endogenous retroviruses (HERVs) are ancient retroviral DNA sequences established into germline. Their tight regulation is mainly achieved by epigenetic mechanisms, which can be altered by environmental factors - viral infections, inflammation, leading to HERV activation. The aberrant expression of HERVs associates with neurological diseases and mood disorders. We showed earlier that HERV-E ƛ 4-1 activation is associated with the recurrent depression stage of exacerbation and are accompanied by a pronounced increase in the proinflammatory activity of the peripheral blood mononuclear cells (PBMC).ObjectivesThe purpose of the study was to evaluate the activity of HERV-E ƛ 4-1 on PBMCs of patients with recurrent depression in remission, including under the influence of recombinant human IL-1β.MethodsThe study included 30 patients with an established diagnosis of recurrent depression (F 33.0) aged 26–45 years. PBMC were isolated using the Ficoll density gradient method and further cultured in the presence or absence of 1 mkg/ml of recombinant human IL-1β for 24 hours. HERV-E λ 4 – 1 env gene expression was determined by the PCR. Cells proliferative activity was determined by H3-thymidine incorporation. Cytokines content in culture supernatants was assessed by ELISA.ResultsIt was shown that in all samples of PBMC cultured without IL-1β the HERV-E λ 4 – 1 env expression was not determined. After the PBMC cocultivation with recombinant human IL-1β, HERV-E λ 4 – 1 env gene expression was determined in 86,7% of cases. The HERV-E ƛ 4-1 activation in PBMC after IL-1β influence was accompanied by increased cells proliferative activity and production of IL-1β, IL-6.ConclusionsOur data indicate that the HERV-E λ 4 – 1 env expression in PBMC of recurrent depression patients in the stage of remission induced by the influence of proinflammatory cytokines, such as IL-1β. This mechanism may be one of the possible regulators of HERV-E λ 4 – 1 activation in recurrent depression.Disclosure of InterestNone Declared

Ancient DNA and osteological analyses of a unique paleo-archive reveal Early Holocene faunal expansion into the Scandinavian Arctic.

Paleo-archives are essential for our understanding of species responses to climate warming, yet such archives are extremely rare in the Arctic. Here, we combine morphological analyses and bulk-bone metabarcoding to investigate a unique chronology of bone deposits sealed in the high-latitude Storsteinhola cave system (68°50' N 16°22' E) in Norway. This deposit dates to a period of climate warming from the end of the Late Glacial [~13 thousand calibrated years before the present (ka cal B.P.)] to the Holocene thermal maximum (~5.6 ka cal B.P.). Paleogenetic analyses allow us to exploit the 1000s of morphologically unidentifiable bone fragments resulting in a high-resolution sequence with 40 different taxa, including species not previously found here. Our record reveals borealization in both the marine and terrestrial environments above the Arctic Circle as a naturally recurring phenomenon in past periods of warming, providing fundamental insights into the ecosystem-wide responses that are ongoing today.

Ancient genome of the Chinese Emperor Wu of Northern Zhou

Emperor Wu (, Wudi) of the Xianbei-led Northern Zhou dynasty, named Yuwen Yong (, 543-578 CE), was a highly influential emperor who reformed the system of regional troops, pacified the Turks, and unified the northern part of the country. His genetic profile and physical characteristics, including his appearance and potential diseases, have garnered significant interest from the academic community and the public.In this study, we have successfully generated a 0.343×-coverage genome of Wudi with 1,011,419 single-nucleotide polymorphisms (SNPs) on the 1240k panel. By analyzing pigmentation-relevant SNPs and conducting cranial CT-based facial reconstruction, we have determined that Wudi possessed a typical East or Northeast Asian appearance. Furthermore, pathogenic SNPs suggest Wudi faced an increased susceptibility to certain diseases, such as stroke. Wudi shared the closest genetic relationship with ancient Khitan and Heishui Mohe samples and modern Daur and Mongolian populations but also showed additional affinity with Yellow River (YR) farmers. We estimated that Wudi derived 61% of his ancestry from ancientNortheast Asians (ANAs) and nearly one-third from YR farmer-related groups. This can likely be attributed to continuous intermarriage between Xianbei royal families, and local Han aristocrats.1,2 Furthermore, our study has revealed genetic diversities among available ancient Xianbei individuals from different regions, suggesting that the formation of the Xianbei was a dynamic process influenced by admixture with surrounding populations.

Double feature: First genetic evidence of a mother-daughter double burial in Roman period Austria

A human double burial combined with a horse interment, discovered in 2004 in the eastern cemetery of the Roman town of Ovilava (today Wels/AUT), has been the subject of a comprehensive interdisciplinary study. This burial was remarkable for two reasons: firstly, the arrangement of the two individuals, with individual 1 having an arm around individual 2, and secondly, the presence of equine skeletal remains in the same burial pit directly below the human remains. Based on this finding, an initial assessment suggested a mixed-sex pair buried together with a horse. The horse burial was interpreted as an indicator of an early medieval date. The position of the two human skeletons suggested that a male and female individual had been buried together. A thorough examination of both the human and horse skeletons disproved these initial interpretations. Radiocarbon dating of the human and horse skeletons dated them to the Roman period. In addition, ancient DNA (aDNA) analysis of the human remains corrected the earlier sex assumption, revealing that the individuals were two biological females who were first-degree relatives. The age difference of 15 to 25 years between the two suggests a probable mother-daughter relationship. Thus, the application of scientific methods confirmed a rare, combined human-horse burial from Roman antiquity and established the first genetically documented mother-daughter burial from this period in present-day Austria.

Reconstructing human history from ancient genomes: an interview with Nobel laureate Svante Pääbo.

Professor Svante Pääbo, Director of the Max Planck Institute for Evolutionary Anthropology, won the Nobel Prize in Physiology or Medicine in 2022 for his discoveries in ancient hominine genomes and human evolution. His pioneering work in sequencing and interpreting the paleo genomes of Neanderthals and Denisovans, as well as their relationship with the modern human genome, was groundbreaking in terms of our understanding of human origins. Nowadays, we can even use commercial kits to easily detect the proportion of Neanderthal genes in our own genomes. Recently, NSR conducted an interview with Professor Pääbo to learn about his interesting work chasing the ancient genomes and reconstructing human evolutionary and migration history from the DNA evidence, as well as his perspective on paleo genome studies and his advice to young researchers: follow your interests and be ready to try some crazy things.

Comparison and optimization of protocols and whole-genome capture conditions for ancient DNA samples.

Ancient DNA (aDNA)obtained from human remains is typically fragmented and present in relatively low amounts. Here we investigate a set of optimal methods for producing aDNA data by comparing silica-based DNA extraction and aDNA library preparation protocols. We also test the efficiency of whole-genome enrichment (WGC) on ancient human samples by modifying a number of parameter combinations. We find that the Dabney extraction protocol performs significantly better than alternatives. We further observed a positive trend with the BEST library protocol indicating lower clonality. Notably, our results suggest that WGC is effective at retrieving endogenous DNA, particularly from poorly-preserved human samples, by increasing human endogenous proportions by 5x. Thus, aDNA studies will be most likely to benefit from our results.

Reconstructing the Genetic Relationship between Ancient and Present-Day Siberian Populations.

Human populations across a vast area in northern Eurasia, from Fennoscandia to Chukotka, share a distinct genetic component often referred to as the Siberian ancestry. Most enriched in present-day Samoyedic-speaking populations such as Nganasans, its origins and history still remain elusive despite the growing list of ancient and present-day genomes from Siberia. Here, we reanalyze published ancient and present-day Siberian genomes focusing on the Baikal and Yakutia, resolving key questions regarding their genetic history. First, we show a long-term presence of a unique genetic profile in southern Siberia, up to 6,000 yr ago, which distinctly shares a deep ancestral connection with Native Americans. Second, we provide plausible historical models tracing genetic changes in West Baikal and Yakutia in fine resolution. Third, the Middle Neolithic individual from Yakutia, belonging to the Belkachi culture, serves as the best source so far available for the spread of the Siberian ancestry into Fennoscandia and Greenland. These findings shed light on the genetic legacy of the Siberian ancestry and provide insights into the complex interplay between different populations in northern Eurasia throughout history.

Isotopic biographies reveal horse rearing and trading networks in medieval London.

This paper reports a high-resolution isotopic study of medieval horse mobility, revealing their origins and in-life mobility both regionally and internationally. The animals were found in an unusual horse cemetery site found within the City of Westminster, London, England. Enamel strontium, oxygen, and carbon isotope analysis of 15 individuals provides information about likely place of birth, diet, and mobility during the first approximately 5 years of life. Results show that at least seven horses originated outside of Britain in relatively cold climates, potentially in Scandinavia or the Western Alps. Ancient DNA sexing data indicate no consistent sex-specific mobility patterning, although three of the five females came from exceptionally highly radiogenic regions. Another female with low mobility is suggested to be a sedentary broodmare. Our results provide direct and unprecedented evidence for a variety of horse movement and trading practices in the Middle Ages and highlight the importance of international trade in securing high-quality horses for medieval London elites.

X-chromosomal STRs in aDNA kinship analysis.

The analysis of ancient DNA (aDNA) from human skeletal remains can provide useful insights when investigating archaeological finds. One popular application of aDNA is to examine genealogical relationships between individuals recovered at the same archaeological site. For the reconstruction of genealogical relationships, several genetic markers are commonly used: autosomal STRs, mitochondrial lineages (based on SNP-analysis) and Y-chromosomal haplotypes (based on Y-STR-analysis). In this paper, we present the additional opportunities that X-STRs provide in aDNA kinship reconstruction, especially in deficiency cases and for the examination of father-daughter relationships. Possible applications are demonstrated on a range of different kinship reconstructions: confirmation of half-siblingship in the Lichtenstein cave (Germany), exclusion of two potential father-daughter relationships in Goslar (Germany), investigation of three siblingships in Boilstädt (Germany) as well as the confirmation of a father-daughter relationship in Stolpe (Germany). This study shows that the analysis of X-STRs can contribute to the investigation of relationship constellations otherwise difficult to approach (e.g. father-daughter relationships) and that X-STRs are useful to support and complement autosomal STRs, mtDNA and Y-STR data.

Ancient Mitogenomes Reveal the Maternal Genetic History of East Asian Dogs.

Recent studies have suggested that dogs were domesticated during the Last Glacial Maximum (LGM) in Siberia, which contrasts with previous proposed domestication centers (e.g. Europe, the Middle East, and East Asia). Ancient DNA provides a powerful resource for the study of mammalian evolution and has been widely used to understand the genetic history of domestic animals. To understand the maternal genetic history of East Asian dogs, we have made a complete mitogenome dataset of 120 East Asian canids from 38 archaeological sites, including 102 newly sequenced from 12.9 to 1 ka BP (1,000 years before present). The majority (112/119, 94.12%) belonged to haplogroup A, and half of these (55/112, 49.11%) belonged to sub-haplogroup A1b. Most existing mitochondrial haplogroups were present in ancient East Asian dogs. However, mitochondrial lineages in ancient northern dogs (northeastern Eurasia and northern East Asia) were deeper and older than those in southern East Asian dogs. Results suggests that East Asian dogs originated from northeastern Eurasian populations after the LGM, dispersing in two possible directions after domestication. Western Eurasian (Europe and the Middle East) dog maternal ancestries genetically influenced East Asian dogs from approximately 4 ka BP, dramatically increasing after 3 ka BP, and afterwards largely replaced most primary maternal lineages in northern East Asia. Additionally, at least three major mitogenome sub-haplogroups of haplogroup A (A1a, A1b, and A3) reveal at least two major dispersal waves onto the Qinghai-Tibet Plateau in ancient times, indicating eastern (A1b and A3) and western (A1a) Eurasian origins.

Simulation-based benchmarking of ancient haplotype inference for detecting population structure

Paleogenomic data has informed us about the movements, growth, and relationships of ancient populations. It has also given us context for medically relevant adaptations that appear in present-day humans due to introgression from other hominids, and it continues to help us characterize the evolutionary history of humans. However, ancient DNA (aDNA) presents several practical challenges as various factors such as deamination, high fragmentation, environmental contamination of aDNA, and low amounts of recoverable endogenous DNA, make aDNA recovery and analysis more difficult than modern DNA. Most studies with aDNA leverage only SNP data, and only a few studies have made inferences on human demographic history based on haplotype data, possibly because haplotype estimation (or phasing) has not yet been systematically evaluated in the context of aDNA. Here, we evaluate how the unique challenges of aDNA can impact phasing and imputation quality, we also present an aDNA simulation pipeline that integrates multiple existing tools, allowing users to specify features of simulated aDNA and the evolutionary history of the simulated populations. We measured phasing error as a function of aDNA quality and demographic history, and found that low phasing error is achievable even for very ancient individuals (∼ 400 generations in the past) as long as contamination and average coverage are adequate. Our results show that population splits or bottleneck events occurring between the reference and phased populations affect phasing quality, with bottlenecks resultingin the highest average error rates. Finally, we found that using estimated haplotypes, even if not completely accurate, is superior to using the simulated genotype data when reconstructing changes in population structure after population splits between present-day and ancient populations. We also find that the imputation of ancient data before phasing can lead to better phasing quality, even in cases where the reference individuals used for imputation are not representative of the ancient individuals.

Simulation-based benchmarking of ancient haplotype inference for detecting population structure

Paleogenomic data has informed us about the movements, growth, and relationships of ancient populations. It has also given us context for medically relevant adaptations that appear in present-day humans due to introgression from other hominids, and it continues to help us characterize the evolutionary history of humans. However, ancient DNA (aDNA) presents several practical challenges as various factors such as deamination, high fragmentation, environmental contamination of aDNA, and low amounts of recoverable endogenous DNA, make aDNA recovery and analysis more difficult than modern DNA. Most studies with aDNA leverage only SNP data, and only a few studies have made inferences on human demographic history based on haplotype data, possibly because haplotype estimation (or phasing) has not yet been systematically evaluated in the context of aDNA. Here, we evaluate how the unique challenges of aDNA can impact phasing and imputation quality, we also present an aDNA simulation pipeline that integrates multiple existing tools, allowing users to specify features of simulated aDNA and the evolutionary history of the simulated populations. We measured phasing error as a function of aDNA quality and demographic history, and found that low phasing error is achievable even for very ancient individuals (∼ 400 generations in the past) as long as contamination and average coverage are adequate. Our results show that population splits or bottleneck events occurring between the reference and phased populations affect phasing quality, with bottlenecks resulting in the highest average error rates. Finally, we found that using estimated haplotypes, even if not completely accurate, is superior to using the simulated genotype data when reconstructing changes in population structure after population splits between present-day and ancient populations. We also find that the imputation of ancient data before phasing can lead to better phasing quality, even in cases where the reference individuals used for imputation are not representative of the ancient individuals.

Exploring the complex pre-adaptations of invasive plants to anthropogenic disturbance: a call for integration of archaeobotanical approaches.

Pre-adaptation to anthropogenic disturbance is broadly considered key for plant invasion success. Nevertheless, empirical evidence remains scarce and fragmentary, given the multifaceted nature of anthropogenic disturbance itself and the complexity of other evolutionary forces shaping the (epi)-genomes of recent native and invasive plant populations. Here, we review and critically revisit the existing theory and empirical evidence in the field of evolutionary ecology and highlight novel integrative research avenues that work at the interface with archaeology to solve open questions. The approaches suggested so far focus on contemporary plant populations, although their genomes have rapidly changed since their initial introduction in response to numerous selective and stochastic forces. We elaborate that a role of pre-adaptation to anthropogenic disturbance in plant invasion success should thus additionally be validated based on the analyses of archaeobotanical remains. Such materials, in the light of detailed knowledge on past human societies could highlight fine-scale differences in the type and timing of past disturbances. We propose a combination of archaeobotanical, ancient DNA and morphometric analyses of plant macro- and microremains to assess past community composition, and species' functional traits to unravel the timing of adaptation processes, their drivers and their long-term consequences for invasive species. Although such methodologies have proven to be feasible for numerous crop plants, they have not been yet applied to wild invasive species, which opens a wide array of insights into their evolution.

Mitochondrial genomes of Pleistocene megafauna retrieved from recent sediment layers of two Siberian lakes

Ancient environmental DNA (aeDNA) from lake sediments has yielded remarkable insights for the reconstruction of past ecosystems, including suggestions of late survival of extinct species. However, translocation and lateral inflow of DNA in sediments can potentially distort the stratigraphic signal of the DNA. Using three different approaches on two short lake sediment cores of the Yamal peninsula, West Siberia, with ages spanning only the past hundreds of years, we detect DNA and identified mitochondrial genomes of multiple mammoth and woolly rhinoceros individuals—both species that have been extinct for thousands of years on the mainland. The occurrence of clearly identifiable aeDNA of extinct Pleistocene megafauna (e.g. >400 K reads in one core) throughout these two short subsurface cores, along with specificities of sedimentology and dating, confirm that processes acting on regional scales, such as extensive permafrost thawing, can influence the aeDNA record and should be accounted for in aeDNA paleoecology.

Mitochondrial genomes of Pleistocene megafauna retrieved from recent sediment layers of two Siberian lakes.

Ancient environmental DNA (aeDNA) from lake sediments has yielded remarkable insights for the reconstruction of past ecosystems, including suggestions of late survival of extinct species. However, translocation and lateral inflow of DNA in sediments can potentially distort the stratigraphic signal of the DNA. Using three different approaches on two short lake sediment cores of the Yamal peninsula, West Siberia, with ages spanning only the past hundreds of years, we detect DNA and identified mitochondrial genomes of multiple mammoth and woolly rhinoceros individuals-both species that have been extinct for thousands of years on the mainland. The occurrence of clearly identifiable aeDNA of extinct Pleistocene megafauna (e.g. >400 K reads in one core) throughout these two short subsurface cores, along with specificities of sedimentology and dating, confirm that processes acting on regional scales, such as extensive permafrost thawing, can influence the aeDNA record and should be accounted for in aeDNA paleoecology.

Assessing the impact of post-mortem damage and contamination on imputation performance in ancient DNA

Low-coverage imputation is becoming ever more present in ancient DNA (aDNA) studies. Imputation pipelines commonly used for present-day genomes have been shown to yield accurate results when applied to ancient genomes. However, post-mortem damage (PMD), in the form of C-to-T substitutions at the reads termini, and contamination with DNA from closely related species can potentially affect imputation performance in aDNA. In this study, we evaluated imputation performance (i) when using a genotype caller designed for aDNA, ATLAS, compared to bcftools, and (ii) when contamination is present. We evaluated imputation performance with principal component analyses and by calculating imputation error rates. With a particular focus on differently imputed sites, we found that using ATLAS prior to imputation substantially improved imputed genotypes for a very damaged ancient genome (42% PMD). Trimming the ends of the sequencing reads led to similar improvements in imputation accuracy. For the remaining genomes, ATLAS brought limited gains. Finally, to examine the effect of contamination on imputation, we added various amounts of reads from two present-day genomes to a previously downsampled high-coverage ancient genome. We observed that imputation accuracy drastically decreased for contamination rates above 5%. In conclusion, we recommend (i) accounting for PMD by either trimming sequencing reads or using a genotype caller such as ATLAS before imputing highly damaged genomes and (ii) only imputing genomes containing up to 5% of contamination.

Development of Genome-Wide Intron Length Polymorphism (ILP) Markers in Tea Plant (Camellia sinensis) and Related Applications for Genetics Research.

The market value of tea is largely dependent on the tea species and cultivar. Therefore, it is important to develop efficient molecular markers covering the entire tea genome that can be used for the identification of tea varieties, marker-assisted breeding, and mapping important quantitative trait loci for beneficial traits. In this study, genome-wide molecular markers based on intron length polymorphism (ILP) were developed for tea trees. A total of 479, 1393, and 1342 tea ILP markers were identified using the PCR method in silico from the 'Shuchazao' scaffold genome, the chromosome-level genome of 'Longjing 43', and the ancient tea DASZ chromosome-level genome, respectively. A total of 230 tea ILP markers were used to amplify six tea tree species. Among these, 213 pairs of primers successfully characterize products in all six species, with 112 primer pairs exhibiting polymorphism. The polymorphism rate of primer pairs increased with the improvement in reference genome assembly quality level. The cross-species transferability analysis of 35 primer pairs of tea ILP markers showed an average amplification rate of 85.17% through 11 species in 6 families, with high transferability in Camellia reticulata and tobacco. We also used 40 pairs of tea ILP primers to evaluate the genetic diversity and population structure of C. tetracocca with 176 plants from Puan County, Guizhou Province, China. These genome-wide markers will be a valuable resource for genetic diversity analysis, marker-assisted breeding, and variety identification in tea, providing important information for the tea industry.