Genetic discontinuity between local hunter-gatherers and central Europe's first farmers

Demographic interactions between the last hunter-gatherers and the first farmers

Demographic interaction processes play a pivotal role during episodes of cultural diffusion between different populations, particularly when these episodes can lead to competition for the same resources and geographic space. The diffusion of farming is one prototypical case within this broader scenario, where groups of incumbent hunter-gatherers occupied a space which would later be claimed by expanding farmers. In this work, we tackle such processes through a two-population mathematical model, where farmers and foragers compete and interact in the same geographic space. We present this work as a conceptual approach where, first, we assess the implications of our theoretical model and its general applicability and, second, we empirically test it on three case studies: Denmark, Eastern Iberia, and the island of Kyushu (Japan). While these regional case studies do not encompass the full range of processes observed in the interaction between migrant farmers and incumbent hunter-gatherers they provide reasonable variation to illustrate how our model can be fitted to a diverse range of empirical data and provide insights into these demographic processes. In particular, our theoretical model and case studies illustrate how endogenous interaction processes alone can explain the demographic fluctuations observed in the archaeological record during this transition, highlighting how these should be accounted for before invoking external forces as primary drivers.

Embracing complexity. Porous cranial lesions and their paleopathological significance in two population samples from Neolithic Northern Germany

OBJECTIVE

To assess phenotypic variation of porous cranial lesions and their co-occurrence with infections of the upper respiratory apparatus and endocranial lesions, to infer disease burden in two different Neolithic socio-economic groups.

MATERIALS

Human skulls of at least 111 individuals from a collective grave at Sorsum (farmers) and 30 individual biurials at Ostorf (aquatic foragers) from northern Germany (c. 3300-2900 BCE).

METHODS

A new data recording protocol for scoring porous cranial lesion phenotypic variation and the assessment of inter- and intra-site frequencies and anatomical distribution. Statistical analysis of lesion frequencies and co-occurrences.

RESULTS

High odds of porous cranial lesions and upper respiratory apparatus lesions co-occurrence, and of subperiosteal new bone formation of the vault (a porous cranial lesion phenotype) and endocranial lesions, are noted for both sites. Site-specific phenotypic profiles and distribution patterns differ. For Sorsum, juvenile individuals show greater porous cranial lesion frequencies and active lesions.

CONCLUSIONS

Considering disease interplay is key for understanding porous cranial lesion phenotypic variation. Disease profiles can be associated with subsistence strategies. The results rule out dichotomic models (e.g. "civilization stress") and support more nuanced reconstructions of the Neolithic social-economic transformations.

SIGNIFICANCE

This study emphasizes the need to adopt data recording protocols that include a wider range of porous cranial lesions to understand overlapping pathophysiological pathways.

LIMITATIONS

Considerable preservation bias of the population samples. Inter-observer error is to be tested. Radiographic analyses are needed to corroborate the results.

SUGGESTIONS FOR FURTHER RESEARCH

Further studies on larger assemblages from different geographical and chronological contexts are needed.

Bioclimatic and masticatory influences on human cranial diversity verified by analysis of 3D morphometric homologous models

This study analyzes the effects of bioclimate and masticatory factors on the regional variability of human cranial forms across 150 ethnic groups worldwide. Morphometric variables were generated using principal component analysis applied to 3D homologous models. Relationships between cranial form and bioclimate (temperature and precipitation) and masticatory factors (infratemporal space) were tested considering sampling bias due to past population movements during the late Pleistocene and/or early- to mid-Holocene. Cranial size correlated with thermal conditions, consistent with Bergmann's rule. The length/breadth proportion of the neurocranium aligned with Allen's rule for thermal adaptation, while no relationship with masticatory stress was found. Facial form responded to either climate or masticatory conditions, although the primary factor was unclear due to the high correlation between stresses. However, masticatory stress was identified as an equally significant factor behind facial flatness in cold regions, else than the effect of Allen's rule. High narrowness of nasal and orbital openings correlated significantly with cold temperatures and cranial size, suggesting not only functional but also allometric effect. This study demonstrated the complexity of environmental influences on cranial form diversity, nonetheless suggested reduction of selective pressure on cranial form caused by natural environmental stress due to the development of civilization.

Interbreeding between farmers and hunter-gatherers along the inland and Mediterranean routes of Neolithic spread in Europe

The Neolithic (i.e., farming and stockbreeding) spread from the Near East across Europe since about 9000 years before the common era (BCE) until about 4000 yr BCE. It followed two main routes, namely a sea route along the northern Mediterranean coast and an inland one across the Balkans and central Europe. It is known that the dispersive behavior of farmers depended on geography, with longer movements along the Mediterranean coast than along the inland route. In sharp contrast, here we show that for both routes the percentage of farmers who interbred with hunter-gatherers and/or acculturated one of them was strikingly the same (about 3.6%). Therefore, whereas the dispersive behavior depended on the proximity to the Mediterranean sea, the interaction behavior (incorporation of hunter-gatherers) did not depend on geographical constraints but only on the transition in the subsistence economy (from hunting and gathering to farming) and its associated way of life. These conclusions are reached by analyzing the clines of haplogroup K, which was virtually absent in hunter-gatherers and the most frequent mitochondrial haplogroup in early farmers. Similarly, the most frequent Y-chromosome Neolithic haplogroup (G2a) displays an inland cline that agrees with the percentage of interbreeding reported above.

Ancient DNA sheds light on the funerary practices of late Neolithic collective burial in southern France

The Aven de la Boucle (Corconne, Gard, southern France) is a karst shaft used as a collective burial between 3600 and 2800 cal BCE. The site encompasses the skeletal remains of approximately 75 individuals comprising a large majority of adult individuals, represented by scattered and commingled remains. To date, few studies have explored the potential of ancient DNA to tackle the documentation of Neolithic collective burials, and the funerary selection rules within such structures remain largely debated. In this study, we combine genomic analysis of 37 individuals with archaeo-anthropological data and Bayesian modelling of radiocarbon dates. Through this multidisciplinary approach, we aim to characterize the identity of the deceased and their relationships, as well as untangle the genetic diversity and funerary dynamics of this community. Genomic results identify 76% of male Neolithic individuals, suggesting a marked sex-biased selection. Available data emphasize the importance of biological relatedness and a male-mediated transmission of social status, as the affiliation to a specific male-lineage appears as a preponderant selection factor. The genomic results argue in favour of 'continuous' deposits between 3600 and 2800 BCE, carried out by the same community, despite cultural changes reflected by the ceramic material.

The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal

A combination of evidence, based on genetic, fossil and archaeological findings, indicates that Homo sapiens spread out of Africa between ~70-60 thousand years ago (kya). However, it appears that once outside of Africa, human populations did not expand across all of Eurasia until ~45 kya. The geographic whereabouts of these early settlers in the timeframe between ~70-60 to 45 kya has been difficult to reconcile. Here we combine genetic evidence and palaeoecological models to infer the geographic location that acted as the Hub for our species during the early phases of colonisation of Eurasia. Leveraging on available genomic evidence we show that populations from the Persian Plateau carry an ancestry component that closely matches the population that settled the Hub outside Africa. With the paleoclimatic data available to date, we built ecological models showing that the Persian Plateau was suitable for human occupation and that it could sustain a larger population compared to other West Asian regions, strengthening this claim.

Vittrup Man-The life-history of a genetic foreigner in Neolithic Denmark

The lethally maltreated body of Vittrup Man was deposited in a Danish bog, probably as part of a ritualised sacrifice. It happened between c. 3300 and 3100 cal years BC, i.e., during the period of the local farming-based Funnel Beaker Culture. In terms of skull morphological features, he differs from the majority of the contemporaneous farmers found in Denmark, and associates with hunter-gatherers, who inhabited Scandinavia during the previous millennia. His skeletal remains were selected for transdisciplinary analysis to reveal his life-history in terms of a population historical perspective. We report the combined results of an integrated set of genetic, isotopic, physical anthropological and archaeological analytical approaches. Strontium signature suggests a foreign birthplace that could be in Norway or Sweden. In addition, enamel oxygen isotope values indicate that as a child he lived in a colder climate, i.e., to the north of the regions inhabited by farmers. Genomic data in fact demonstrates that he is closely related to Mesolithic humans known from Norway and Sweden. Moreover, dietary stable isotope analyses on enamel and bone collagen demonstrate a fisher-hunter way of life in his childhood and a diet typical of farmers later on. Such a variable life-history is also reflected by proteomic analysis of hardened organic deposits on his teeth, indicating the consumption of forager food (seal, whale and marine fish) as well as farmer food (sheep/goat). From a dietary isotopic transect of one of his teeth it is shown that his transfer between societies of foragers and farmers took place near to the end of his teenage years.

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.

Human evolution: When admixture met selection

Admixture has been a major force during human evolution. Two new studies using ancient DNA now show how two key admixture events in the evolutionary history of Europeans altered their adaptive trajectories and facilitated rapid evolution.

Phylogeographic history of mitochondrial haplogroup J in Scandinavia

BACKGROUND

Mitochondrial DNA haplogroup J is the third most frequent haplogroup in modern-day Scandinavia, although it did not originate there. To infer the genetic history of haplogroup J in Scandinavia, we examined worldwide mitogenome sequences using a maximum-likelihood phylogenetic approach.

METHODS

Haplogroup J mitogenome sequences were gathered from GenBank (n = 2245) and aligned against the ancestral Reconstructed Sapiens Reference Sequence. We also analyzed haplogroup J Viking Age sequences from the European Nucleotide Archive (n = 54). Genetic distances were estimated from these data and projected onto a maximum likelihood rooted phylogenetic tree to analyze clustering and branching dates.

RESULTS

Haplogroup J originated approximately 42.6 kya (95% CI: 30.0-64.7), with several of its earliest branches being found within the Arabian Peninsula and Northern Africa. J1b was found most frequently in the Near East and Arabian Peninsula, while J1c occurred most frequently in Europe. Based on phylogenetic dating, subhaplogroup J1c has its early roots in the Mediterranean and Western Balkans. Otherwise, the majority of the branches found in Scandinavia are younger than those seen elsewhere, indicating that haplogroup J dispersed relatively recently into Northern Europe, most plausibly with Neolithic farmers.

CONCLUSIONS

Haplogroup J appeared when Scandinavia was transitioning to agriculture over 6 kya, with J1c being the most common lineage there today. Changes in the distribution of haplogroup J mtDNAs were likely driven by the expansion of farming from West Asia into Southern Europe, followed by a later expansion into Scandinavia, with other J subhaplogroups appearing among Scandinavian groups as early as the Viking Age.

Neolithic genomic data from southern France showcase intensified interactions with hunter-gatherer communities

Archaeological research shows that the dispersal of the Neolithic took a more complex turn when reaching western Europe, painting a contrasted picture of interactions between autochthonous hunter-gatherers (HGs) and incoming farmers. In order to clarify the mode, the intensity, and the regional variability of biological exchanges implied in these processes, we report new palaeogenomic data from Occitanie, a key region in Southern France. Genomic data from 28 individuals originating from six sites spanning from c. 5,500 to c. 2,500 BCE allow us to characterize regional patterns of ancestries throughout the Neolithic period. Results highlight major differences between the Mediterranean and Continental Neolithic expansion routes regarding both migration and interaction processes. High proportions of HG ancestry in both Early and Late Neolithic groups in Southern France support multiple pulses of inter-group gene flow throughout time and space and confirm the need for regional studies to address the complexity of the processes involved.

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Genome-wide data from 28 individuals from Southern France (∼5,500–∼2,500 BCE)

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Small groups associated with the Neolithic expansion along the Mediterranean

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Early admixture between hunter-gatherers and Neolithic farmers in Southern France

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Multiple pulses of HG legacy introgression in Western Europe throughout Neolithic

Ancient mitochondrial diversity reveals population homogeneity in Neolithic Greece and identifies population dynamics along the Danubian expansion axis

The aim of the study is to investigate mitochondrial diversity in Neolithic Greece and its relation to hunter-gatherers and farmers who populated the Danubian Neolithic expansion axis. We sequenced 42 mitochondrial palaeogenomes from Greece and analysed them together with European set of 328 mtDNA sequences dating from the Early to the Final Neolithic and 319 modern sequences. To test for population continuity through time in Greece, we use an original structured population continuity test that simulates DNA from different periods by explicitly considering the spatial and temporal dynamics of populations. We explore specific scenarios of the mode and tempo of the European Neolithic expansion along the Danubian axis applying spatially explicit simulations coupled with Approximate Bayesian Computation. We observe a striking genetic homogeneity for the maternal line throughout the Neolithic in Greece whereas population continuity is rejected between the Neolithic and present-day Greeks. Along the Danubian expansion axis, our best-fitting scenario supports a substantial decrease in mobility and an increasing local hunter-gatherer contribution to the gene-pool of farmers following the initial rapid Neolithic expansion. Οur original simulation approach models key demographic parameters rather than inferring them from fragmentary data leading to a better understanding of this important process in European prehistory.

Variation in the substitution rates among the human mitochondrial haplogroup U sublineages

Resolving the absolute timescale of phylogenetic trees stipulates reliable estimates for the rate of DNA sequence evolution. For this end, various calibration methods have been developed and studied intensively. Intraspecific rate variation among distinct genetic lineages, however, has gained less attention. Here, we have assessed lineage-specific molecular rates of human mitochondrial DNA (mtDNA) by performing tip-calibrated Bayesian phylogenetic analyses. Tip-calibration, as opposed to traditional nodal time stamps from dated fossil evidence or geological events, is based on sample ages and becoming ever more feasible as ancient DNA data from radiocarbon-dated samples accumulate. We focus on subhaplogroups U2, U4, U5a, and U5b, the data including ancient mtDNA genomes from ¹⁴C-dated samples (n = 234), contemporary genomes (n = 301), and two outgroup sequences from haplogroup R. The obtained molecular rates depended on the data sets (with or without contemporary sequences), suggesting time-dependency. More notable was the rate variation between haplogroups: U4 and U5a stand out having a substantially higher rate than U5b. This is also reflected in the divergence times obtained (U5a: 17,700 years and U5b: 29,700 years), a disparity not reported previously. After ruling out various alternative causes (e.g., selection, sampling, and sequence quality), we propose that the substitution rates have been influenced by demographic histories, widely different among populations where U4/U5a or U5b are frequent. As with the Y-chromosomal subhaplogroup R1b, the mitochondrial U4 and U5a have been associated with remarkable range extensions of the Yamnaya culture in the Bronze Age.

The spatiotemporal patterns of major human admixture events during the European Holocene

Recent studies have shown that admixture has been pervasive throughout human history. While several methods exist for dating admixture in contemporary populations, they are not suitable for sparse, low coverage ancient genomic data. Thus, we developed DATES (Distribution of Ancestry Tracts of Evolutionary Signals) that leverages ancestry covariance patterns across the genome of a single individual to infer the timing of admixture. DATES provides reliable estimates under various demographic scenarios and outperforms available methods for ancient DNA applications. Using DATES on~1100 ancient genomes from sixteen regions in Europe and west Asia, we reconstruct the chronology of the formation of the ancestral populations and the fine-scale details of the spread of Neolithic farming and Steppe pastoralist-related ancestry across Europe. By studying the genetic formation of Anatolian farmers, we infer that gene flow related to Iranian Neolithic farmers occurred before 9600 BCE, predating the advent of agriculture in Anatolia. Contrary to the archaeological evidence, we estimate that early Steppe pastoralist groups (Yamnaya and Afanasievo) were genetically formed more than a millennium before the start of Steppe pastoralism. Our analyses provide new insights on the origins and spread of farming and Indo-European languages, highlighting the power of genomic dating methods to elucidate the legacy of human migrations.

The genomic origins of the world's first farmers

The precise genetic origins of the first Neolithic farming populations in Europe and Southwest Asia, as well as the processes and the timing of their differentiation, remain largely unknown. Demogenomic modeling of high-quality ancient genomes reveals that the early farmers of Anatolia and Europe emerged from a multiphase mixing of a Southwest Asian population with a strongly bottlenecked western hunter-gatherer population after the last glacial maximum. Moreover, the ancestors of the first farmers of Europe and Anatolia went through a period of extreme genetic drift during their westward range expansion, contributing highly to their genetic distinctiveness. This modeling elucidates the demographic processes at the root of the Neolithic transition and leads to a spatial interpretation of the population history of Southwest Asia and Europe during the late Pleistocene and early Holocene.

Evolution and dispersal of mitochondrial DNA haplogroup U5 in Northern Europe: insights from an unsupervised learning approach to phylogeography

Background

We combined an unsupervised learning methodology for analyzing mitogenome sequences with maximum likelihood (ML) phylogenetics to make detailed inferences about the evolution and diversification of mitochondrial DNA (mtDNA) haplogroup U5, which appears at high frequencies in northern Europe.

Methods

Haplogroup U5 mitogenome sequences were gathered from GenBank. The hierarchal Bayesian Analysis of Population Structure (hierBAPS) method was used to generate groups of sequences that were then projected onto a rooted maximum likelihood (ML) phylogenetic tree to visualize the pattern of clustering. The haplogroup statuses of the individual sequences were assessed using Haplogrep2.

Results

A total of 23 hierBAPS groups were identified, all of which corresponded to subclades defined in Phylotree, v.17. The hierBAPS groups projected onto the ML phylogeny accurately clustered all haplotypes belonging to a specific haplogroup in accordance with Haplogrep2. By incorporating the geographic source of each sequence and subclade age estimates into this framework, inferences about the diversification of U5 mtDNAs were made. Haplogroup U5 has been present in northern Europe since the Mesolithic, and spread in both eastern and western directions, undergoing significant diversification within Scandinavia. A review of historical and archeological evidence attests to some of the population interactions contributing to this pattern.

Conclusions

The hierBAPS algorithm accurately grouped mitogenome sequences into subclades in a phylogenetically robust manner. This analysis provided new insights into the phylogeographic structure of haplogroup U5 diversity in northern Europe, revealing a detailed perspective on the diversity of subclades in this region and their distribution in Scandinavian populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08572-y.

Ancient DNA gives new insights into a Norman Neolithic monumental cemetery dedicated to male elites

By integrating genomic and archaeological data, we provide new insights into the Neolithic French monumental site of Fleury-sur-Orne in Normandy, where a group of selected individuals was buried in impressively long monuments. The earliest individuals buried at Fleury-sur-Orne match the expected western European Neolithic genetic diversity, while three individuals, designated as genetic outliers, were buried after 4,000 calibrated BCE. We hypothesize that different, unrelated families or clans used the site over several centuries. Thirteen of 14 of the analyzed individuals were male, indicating an overarching patrilineal system. However, one exception, a female buried with a symbolically male artifact, suggests that the embodiment of the male gender in death was required to access burial at the monumental structures.

The Middle Neolithic in western Europe is characterized by monumental funerary structures, known as megaliths, along the Atlantic façade. The first manifestations of this phenomenon occurred in modern-day France with the long mounds of the Cerny culture. Here, we present genome-wide data from the fifth-millennium BCE site of Fleury-sur-Orne in Normandy (France), famous for its impressively long monuments built for selected individuals. The site encompasses 32 monuments of variable sizes, containing the burials of 19 individuals from the Neolithic period. To address who was buried at the site, we generated genome-wide data for 14 individuals, of whom 13 are males, completing previously published data [M. Rivollat et al., Sci. Adv. 6, eaaz5344 (2020)]. Population genetic and Y chromosome analyses show that the Fleury-sur-Orne group fits within western European Neolithic genetic diversity and that the arrival of a new group is detected after 4,000 calibrated BCE. The results of analyzing uniparentally inherited markers and an overall low number of long runs of homozygosity suggest a patrilineal group practicing female exogamy. We find two pairs of individuals to be father and son, buried together in the same monument/grave. No other biological relationship can link monuments together, suggesting that each monument was dedicated to a genetically independent lineage. The combined data and documented father–son line of descent suggest a male-mediated transmission of sociopolitical authority. However, a single female buried with an arrowhead, otherwise considered a symbol of power of the male elite of the Cerny culture, questions a strictly biological sex bias in the burial rites of this otherwise “masculine” monumental cemetery.

Genomic and dietary discontinuities during the Mesolithic and Neolithic in Sicily

Sicily is a key region for understanding the agricultural transition in the Mediterranean because of its central position. Here, we present genomic and stable isotopic data for 19 prehistoric Sicilians covering the Mesolithic to Bronze Age periods (10,700–4,100 yBP). We find that Early Mesolithic hunter-gatherers (HGs) from Sicily are a highly drifted lineage of the Early Holocene western European HGs, whereas Late Mesolithic HGs carry ∼20% ancestry related to northern and (south) eastern European HGs, indicating substantial gene flow. Early Neolithic farmers are genetically most similar to farmers from the Balkans and Greece, with only ∼7% of ancestry from local Mesolithic HGs. The genetic discontinuities during the Mesolithic and Early Neolithic match the changes in material culture and diet. Three outlying individuals dated to ∼8,000 yBP; however, suggest that hunter-gatherers interacted with incoming farmers at Grotta dell’Uzzo, resulting in a mixed economy and diet for a brief interlude at the Mesolithic-Neolithic transition.

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Genetic transition between Early Mesolithic and Late Mesolithic hunter-gatherers

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A near-complete genetic turnover during the Mesolithic-Neolithic transition

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Exchange of subsistence practices between hunter-gatherers and early farmers

Hunter-gatherer genomes reveal diverse demographic trajectories during the rise of farming in Eastern Africa

The fate of hunting and gathering populations following the rise of agriculture and pastoralism remains a topic of debate in the study of human prehistory. Studies of ancient and modern genomes have found that autochthonous groups were largely replaced by expanding farmer populations with varying levels of gene flow, a characterization that is influenced by the almost universal focus on the European Neolithic.1-5 We sought to understand the demographic impact of an ongoing cultural transition to farming in Southwest Ethiopia, one of the last regions in Africa to experience such shifts.6 Importantly, Southwest Ethiopia is home to several of the world's remaining hunter-gatherer groups, including the Chabu people, who are currently transitioning away from their traditional mode of subsistence.7 We generated genome-wide data from the Chabu and four neighboring populations, the Majang, Shekkacho, Bench, and Sheko, to characterize their genetic ancestry and estimate their effective population sizes over the last 60 generations. We show that the Chabu are a distinct population closely related to ancient people who occupied Southwest Ethiopia >4,500 years ago. Furthermore, the Chabu are undergoing a severe population bottleneck, which began approximately 1,400 years ago. By analyzing eleven Eastern African populations, we find evidence for divergent demographic trajectories among hunter-gatherer-descendant groups. Our results illustrate that although foragers respond to encroaching agriculture and pastoralism with multiple strategies, including cultural adoption of agropastoralism, gene flow, and economic specialization, they often face population decline.

Mitochondrial DNA Consensus Calling and Quality Filtering for Constructing Ancient Human Mitogenomes: Comparison of Two Widely Applied Methods

Retrieving high-quality endogenous ancient DNA (aDNA) poses several challenges, including low molecular copy number, high rates of fragmentation, damage at read termini, and potential presence of exogenous contaminant DNA. All these factors complicate a reliable reconstruction of consensus aDNA sequences in reads from high-throughput sequencing platforms. Here, we report findings from a thorough evaluation of two alternative tools (ANGSD and schmutzi) aimed at overcoming these issues and constructing high-quality ancient mitogenomes. Raw genomic data (BAM/FASTQ) from a total of 17 previously published whole ancient human genomes ranging from the 14th to the 7th millennium BCE were retrieved and mitochondrial consensus sequences were reconstructed using different quality filters, with their accuracy measured and compared. Moreover, the influence of different sequence parameters (number of reads, sequenced bases, mean coverage, and rate of deamination and contamination) as predictors of derived sequence quality was evaluated. Complete mitogenomes were successfully reconstructed for all ancient samples, and for the majority of them, filtering substantially improved mtDNA consensus calling and haplogroup prediction. Overall, the schmutzi pipeline, which estimates and takes into consideration exogenous contamination, appeared to have the edge over the much faster and user-friendly alternative method (ANGSD) in moderate to high coverage samples (>1,000,000 reads). ANGSD, however, through its read termini trimming filter, showed better capabilities in calling the consensus sequence from low-quality samples. Among all the predictors of overall sample quality examined, the strongest correlation was found for the available number of sequence reads and bases. In the process, we report a previously unassigned haplogroup (U3b) for an Early Chalcolithic individual from Southern Anatolia/Northern Levant.

Simulated patterns of mitochondrial diversity are consistent with partial population turnover in Bronze Age Central Europe

OBJECTIVES

The analysis of ancient mitochondrial DNA from osteological remains has challenged previous conclusions drawn from the analysis of mitochondrial DNA from present populations, notably by revealing an absence of genetic continuity between the Neolithic and modern populations in Central Europe. Our study investigates how to reconcile these contradictions at the mitochondrial level using a modeling approach.

MATERIALS AND METHODS

We used a spatially explicit computational framework to simulate ancient and modern DNA sequences under various evolutionary scenarios of post Neolithic demographic events and compared the genetic diversity of the simulated and observed mitochondrial sequences. We investigated which-if any-scenarios were able to reproduce statistics of genetic diversity similar to those observed, with a focus on the haplogroup N1a, associated with the spread of early Neolithic farmers.

RESULTS

Demographic fluctuations during the Neolithic transition or subsequent demographic collapses after this period, that is, due to epidemics such as plague, are not sufficient to explain the signal of population discontinuity detected on the mitochondrial DNA in Central Europe. Only a scenario involving a substantial genetic input due to the arrival of migrants after the Neolithic transition, possibly during the Bronze Age, is compatible with observed patterns of genetic diversity.

DISCUSSION

Our results corroborate paleogenomic studies, since out of the alternative hypotheses tested, the best one that was able to recover observed patterns of mitochondrial diversity in modern and ancient Central European populations was one were immigration of populations from the Pontic steppes during the Bronze Age was explicitly simulated.

The Lady from Basel's Barfüsserkirche - Molecular confirmation of the Mummy's identity through mitochondrial DNA of living relatives spanning 22 generations

The identity of the mummified Lady from the Barfüsser Church in Basel, Switzerland has been unsolved for decades, despite the prominent location of the burial place in front of the choir screen. A recent multidisciplinary research approach came up with a possible candidate, Anna Catharina Bischoff who died in Basel in 1787 with an age of 69 years (1719-1787). To verify the identity of the mummy, genealogists of the Citizen Science Basel discovered three living individuals of the maternal lineage of two different family branches, separated from Anna Catharina Bischoff by up to 22 generations. In this study we compare the ancient mitochondrial DNA of the mummy recovered from a premolar to the mitochondrial DNA of these three candidates. Initially the mitochondrial hypervariable regions I and II of the living individuals were screened using the Sanger sequencing method. This was followed by a mitochondrial capture approach and next generation sequencing to enrich for the whole mitochondrial genome of the mummy and one living person. A full mitochondrial genome has been recovered of both individuals sharing an identical haplotype. The sequence was assigned to the mitochondrial haplogroup U5a1+!16192 including two private mutations 10006G and 16293C. Only by using an interdisciplinary approach combining ancient DNA analysis and genealogy a maternal lineage of a non-noble family spanning 22 generations could be confirmed.

Evolution of Lactase Persistence: Turbo-Charging Adaptation in Growth Under the Selective Pressure of Maternal Mortality?

The emergence of the capacity to digest milk in some populations represents a landmark in human evolution, linking genetic change with a component of niche construction, namely dairying. Alleles promoting continued activity of the enzyme lactase through the life-course (lactase persistence) evolved in several global regions within the last 7,000 years. In some European regions, these alleles underwent rapid selection and must have profoundly affected fertility or mortality. Elsewhere, alleles spread more locally. However, the functional benefits underlying the rapid spread of lactase persistence remain unclear. Here, we set out the hypothesis that lactase persistence promoted skeletal growth, thereby offering a generic rapid solution to childbirth complications arising from exposure to ecological change, or to new environments through migration. Since reduced maternal growth and greater neonatal size both increase the risk of obstructed labour, any ecological exposure impacting these traits may increase maternal mortality risk. Over many generations, maternal skeletal dimensions could adapt to new ecological conditions through genetic change. However, this adaptive strategy would fail if ecological change was rapid, including through migration into new niches. We propose that the combination of consuming milk and lactase persistence could have reduced maternal mortality by promoting growth of the pelvis after weaning, while high calcium intake would reduce risk of pelvic deformities. Our conceptual framework provides locally relevant hypotheses to explain selection for lactase persistence in different global regions. For any given diet and individual genotype, the combination of lactase persistence and milk consumption would divert more energy to skeletal growth, either increasing pelvic dimensions or buffering them from worsening ecological conditions. The emergence of lactase persistence among dairying populations could have helped early European farmers adapt rapidly to northern latitudes, East African pastoralists adapt to sudden climate shifts to drier environments, and Near Eastern populations counteract secular declines in height associated with early agriculture. In each case, we assume that lactase persistence accelerated the timescale over which maternal skeletal dimensions could change, thus promoting both maternal and offspring survival. Where lactase persistence did not emerge, birth weight was constrained at lower levels, and this contributes to contemporary variability in diabetes risk.

Where Asia meets Europe - recent insights from ancient human genomics

CONTEXT

The peopling of Europe by modern humans is a widely debated topic in the field of modern and ancient genomics. While several recent syntheses have focussed on this topic, little has been discussed about the genetic history of populations in the continent's surrounding regions.

OBJECTIVE

We explore genetic transformations in three key areas that played an essential role in the formation of the European genetic landscape through time, focussing on the periods spanning from the Epipalaeolithic/Mesolithic and up until the Iron Age.

METHODS

We review published ancient genomic studies and integrate the associated data to provide a quantification and visualisation of major trends in the population histories of the Near East, the western Eurasian Steppe and North East Europe.

RESULTS

We describe cross-regional as well as localised prehistoric demographic shifts and discuss potential research directions while highlighting geo-temporal gaps in the data.

CONCLUSION

In recent years, archaeogenetic studies have contributed to the understanding of human genetic diversity through time in regions located at the doorstep of Europe. Further studies focussing on these areas will allow for a better characterisation of genetic shifts and regionally-specific patterns of admixture across western Eurasia.

Dynamic changes in genomic and social structures in third millennium BCE central Europe

Europe's prehistory oversaw dynamic and complex interactions of diverse societies, hitherto unexplored at detailed regional scales. Studying 271 human genomes dated ~4900 to 1600 BCE from the European heartland, Bohemia, we reveal unprecedented genetic changes and social processes. Major migrations preceded the arrival of "steppe" ancestry, and at ~2800 BCE, three genetically and culturally differentiated groups coexisted. Corded Ware appeared by 2900 BCE, were initially genetically diverse, did not derive all steppe ancestry from known Yamnaya, and assimilated females of diverse backgrounds. Both Corded Ware and Bell Beaker groups underwent dynamic changes, involving sharp reductions and complete replacements of Y-chromosomal diversity at ~2600 and ~2400 BCE, respectively, the latter accompanied by increased Neolithic-like ancestry. The Bronze Age saw new social organization emerge amid a ≥40% population turnover.

Using Y-chromosome capture enrichment to resolve haplogroup H2 shows new evidence for a two-path Neolithic expansion to Western Europe

Uniparentally-inherited markers on mitochondrial DNA (mtDNA) and the non-recombining regions of the Y chromosome (NRY), have been used for the past 30 years to investigate the history of humans from a maternal and paternal perspective. Researchers have preferred mtDNA due to its abundance in the cells, and comparatively high substitution rate. Conversely, the NRY is less susceptible to back mutations and saturation, and is potentially more informative than mtDNA owing to its longer sequence length. However, due to comparatively poor NRY coverage via shotgun sequencing, and the relatively low and biased representation of Y-chromosome variants on capture assays such as the 1240 k, ancient DNA studies often fail to utilize the unique perspective that the NRY can yield. Here we introduce a new DNA enrichment assay, coined YMCA (Y-mappable capture assay), that targets the "mappable" regions of the NRY. We show that compared to low-coverage shotgun sequencing and 1240 k capture, YMCA significantly improves the mean coverage and number of sites covered on the NRY, increasing the number of Y-haplogroup informative SNPs, and allowing for the identification of previously undiscovered variants. To illustrate the power of YMCA, we show that the analysis of ancient Y-chromosome lineages can help to resolve Y-chromosomal haplogroups. As a case study, we focus on H2, a haplogroup associated with a critical event in European human history: the Neolithic transition. By disentangling the evolutionary history of this haplogroup, we further elucidate the two separate paths by which early farmers expanded from Anatolia and the Near East to western Europe.

Population dynamics in the Japanese Archipelago since the Pleistocene revealed by the complete mitochondrial genome sequences

The Japanese Archipelago is widely covered with acidic soil made of volcanic ash, an environment which is detrimental to the preservation of ancient biomolecules. More than 10,000 Palaeolithic and Neolithic sites have been discovered nationwide, but few skeletal remains exist and preservation of DNA is poor. Despite these challenging circumstances, we succeeded in obtaining a complete mitogenome (mitochondrial genome) sequence from Palaeolithic human remains. We also obtained those of Neolithic (the hunting-gathering Jomon and the farming Yayoi cultures) remains, and over 2,000 present-day Japanese. The Palaeolithic mitogenome sequence was not found to be a direct ancestor of any of Jomon, Yayoi, and present-day Japanese people. However, it was an ancestral type of haplogroup M, a basal group of the haplogroup M. Therefore, our results indicate continuity in the maternal gene pool from the Palaeolithic to present-day Japanese. We also found that a vast increase of population size happened and has continued since the Yayoi period, characterized with paddy rice farming. It means that the cultural transition, i.e. rice agriculture, had significant impact on the demographic history of Japanese population.

Ancient genomes provide insights into family structure and the heredity of social status in the early Bronze Age of southeastern Europe

Twenty-four palaeogenomes from Mokrin, a major Early Bronze Age necropolis in southeastern Europe, were sequenced to analyse kinship between individuals and to better understand prehistoric social organization. 15 investigated individuals were involved in genetic relationships of varying degrees. The Mokrin sample resembles a genetically unstructured population, suggesting that the community’s social hierarchies were not accompanied by strict marriage barriers. We find evidence for female exogamy but no indications for strict patrilocality. Individual status differences at Mokrin, as indicated by grave goods, support the inference that females could inherit status, but could not transmit status to all their sons. We further show that sons had the possibility to acquire status during their lifetimes, but not necessarily to inherit it. Taken together, these findings suggest that Southeastern Europe in the Early Bronze Age had a significantly different family and social structure than Late Neolithic and Early Bronze Age societies of Central Europe.

Sometimes hidden but always there: the assumptions underlying genetic inference of demographic histories

Demographic processes directly affect patterns of genetic variation within contemporary populations as well as future generations, allowing for demographic inference from patterns of both present-day and past genetic variation. Advances in laboratory procedures, sequencing and genotyping technologies in the past decades have resulted in massive increases in high-quality genome-wide genetic data from present-day populations and allowed retrieval of genetic data from archaeological material, also known as ancient DNA. This has resulted in an explosion of work exploring past changes in population size, structure, continuity and movement. However, as genetic processes are highly stochastic, patterns of genetic variation only indirectly reflect demographic histories. As a result, past demographic processes need to be reconstructed using an inferential approach. This usually involves comparing observed patterns of variation with model expectations from theoretical population genetics. A large number of approaches have been developed based on different population genetic models that each come with assumptions about the data and underlying demography. In this article I review some of the key models and assumptions underlying the most commonly used approaches for past demographic inference and their consequences for our ability to link the inferred demographic processes to the archaeological and climate records. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.

Pama-Nyungan grandparent systems change with grandchildren, but not cross-cousin terms or social norms

Kinship is a fundamental and universal aspect of the structure of human society. The kinship category of 'grandparents' is socially salient, due to grandparents' investment in the care of the grandchildren as well as to older generations' control of wealth and cultural knowledge, but the evolutionary dynamics of grandparent terms has yet to be studied in a phylogenetically explicit context. Here, we present the first phylogenetic comparative study of grandparent terms by investigating 134 languages in Pama-Nyungan, an Australian family of hunter-gatherer languages. We infer that proto-Pama-Nyungan had, with high certainty, four separate terms for grandparents. This state then shifted into either a two-term system that distinguishes the genders of the grandparents or a three-term system that merges the 'parallel' grandparents, which could then transition into a different three-term system that merges the 'cross' grandparents. We find no support for the co-evolution of these systems with either community marriage organisation or post-marital residence. We find some evidence for the correlation of grandparent and grandchild terms, but no support for the correlation of grandparent and cross-cousin terms, suggesting that grandparents and grandchildren potentially form a single lexical category but that the entire kinship system does not necessarily change synchronously.

Ancient genome-wide DNA from France highlights the complexity of interactions between Mesolithic hunter-gatherers and Neolithic farmers

Starting from 12,000 years ago in the Middle East, the Neolithic lifestyle spread across Europe via separate continental and Mediterranean routes. Genomes from early European farmers have shown a clear Near Eastern/Anatolian genetic affinity with limited contribution from hunter-gatherers. However, no genomic data are available from modern-day France, where both routes converged, as evidenced by a mosaic cultural pattern. Here, we present genome-wide data from 101 individuals from 12 sites covering today's France and Germany from the Mesolithic (N = 3) to the Neolithic (N = 98) (7000-3000 BCE). Using the genetic substructure observed in European hunter-gatherers, we characterize diverse patterns of admixture in different regions, consistent with both routes of expansion. Early western European farmers show a higher proportion of distinctly western hunter-gatherer ancestry compared to central/southeastern farmers. Our data highlight the complexity of the biological interactions during the Neolithic expansion by revealing major regional variations.

Mitochondrial genomes from Bronze Age Poland reveal genetic continuity from the Late Neolithic and additional genetic affinities with the steppe populations

OBJECTIVE

In this work we aim to investigate the origins and genetic affinities of Bronze Age populations (2,400-1,100 BC) from the region of southern Poland and to trace maternal kinship patterns present in the burials of those populations by the use of complete mitochondrial genomes.

MATERIALS AND METHODS

We performed ancient DNA analyses for Bronze Age individuals from present-day Poland associated with the Strzyżow culture, the Mierzanowice culture, and the Trzciniec Cultural circle. To obtain complete mitochondrial genomes, we sequenced genomic libraries using Illumina platform. Additionally, hybridization capture was used to enrich some of the samples for mitochondrial DNA. AMS ¹⁴ C-dating was conducted for 51 individuals to verify chronological and cultural attribution of the analyzed samples.

RESULTS

Complete ancient mitochondrial genomes were generated for 80 of the Bronze Age individuals from present-day Poland. The results of the population genetic analyses indicate close maternal genetic affinity between Mierzanowice, Trzciniec, and Corded Ware culture-associated populations. This is in contrast to the genetically more distant Strzyżów people that displayed closer maternal genetic relation to steppe populations associated with the preceding Yamnaya culture and Catacomb culture, and with later Scythians. Potential maternal kinship relations were identified in burials of Mierzanowice and Trzciniec populations analyzed in this study.

DISCUSSION

Results revealed genetic continuity from the Late Neolithic Corded Ware groups to Bronze Age Mierzanowice and Trzciniec-associated populations, and possible additional genetic contribution from the steppe to the formation of the Strzyżów-associated group at the end of 3rd millennium BC. Mitochondrial patterns indicated several pairs of potentially maternally related individuals mostly in Trzciniec-associated group.

Inference of natural selection from ancient DNA

Evolutionary processes, including selection, can be indirectly inferred based on patterns of genomic variation among contemporary populations or species. However, this often requires unrealistic assumptions of ancestral demography and selective regimes. Sequencing ancient DNA from temporally spaced samples can inform about past selection processes, as time series data allow direct quantification of population parameters collected before, during, and after genetic changes driven by selection. In this Comment and Opinion, we advocate for the inclusion of temporal sampling and the generation of paleogenomic datasets in evolutionary biology, and highlight some of the recent advances that have yet to be broadly applied by evolutionary biologists. In doing so, we consider the expected signatures of balancing, purifying, and positive selection in time series data, and detail how this can advance our understanding of the chronology and tempo of genomic change driven by selection. However, we also recognize the limitations of such data, which can suffer from postmortem damage, fragmentation, low coverage, and typically low sample size. We therefore highlight the many assumptions and considerations associated with analyzing paleogenomic data and the assumptions associated with analytical methods.

Ancient cattle genomics, origins, and rapid turnover in the Fertile Crescent

Genome-wide analysis of 67 ancient Near Eastern cattle, Bos taurus, remains reveals regional variation that has since been obscured by admixture in modern populations. Comparisons of genomes of early domestic cattle to their aurochs progenitors identify diverse origins with separate introgressions of wild stock. A later region-wide Bronze Age shift indicates rapid and widespread introgression of zebu, Bos indicus, from the Indus Valley. This process was likely stimulated at the onset of the current geological age, ~4.2 thousand years ago, by a widespread multicentury drought. In contrast to genome-wide admixture, mitochondrial DNA stasis supports that this introgression was male-driven, suggesting that selection of arid-adapted zebu bulls enhanced herd survival. This human-mediated migration of zebu-derived genetics has continued through millennia, altering tropical herding on each continent.

Range-wide patterns of human-mediated hybridisation in European wildcats

Hybridisation between wild taxa and their domestic congeners is a significant conservation issue. Domestic species frequently outnumber their wild relatives in population size and distribution and may therefore genetically swamp the native species. The European wildcat (Felis silvestris) has been shown to hybridise with domestic cats (Felis catus). Previously suggested spatially divergent introgression levels have not been confirmed on a European scale due to significant differences in the applied methods to assess hybridisation of the European wildcat. We analysed 926 Felis spp. samples from 13 European countries, using a set of 86 selected ancestry-informative SNPs, 14 microsatellites, and ten mitochondrial and Y-chromosome markers to study regional hybridisation and introgression patterns and population differentiation. We detected 51 hybrids (four F1 and 47 F2 or backcrosses) and 521 pure wildcats throughout Europe. The abundance of hybrids varied considerably among studied populations. All samples from Scotland were identified as F2 hybrids or backcrosses, supporting previous findings that the genetic integrity of that wildcat population has been seriously compromised. In other European populations, low to moderate levels of hybridisation were found, with the lowest levels being in Central and Southeast Europe. The occurrence of distinct maternal and paternal markers between wildcat and domestic cat suggests that there were no severe hybridisation episodes in the past. The overall low (< 1%) prevalence of F1 hybrids suggests a low risk of hybridisation for the long-term genetic integrity of the wildcat in most of Europe. However, regionally elevated introgression rates confirm that hybridisation poses a potential threat. We propose regional in-depth monitoring of hybridisation rates to identify factors driving hybridisation so as to develop effective strategies for conservation.

Interactions between earliest Linearbandkeramik farmers and central European hunter gatherers at the dawn of European Neolithization

Archaeogenetic research over the last decade has demonstrated that European Neolithic farmers (ENFs) were descended primarily from Anatolian Neolithic farmers (ANFs). ENFs, including early Neolithic central European Linearbandkeramik (LBK) farming communities, also harbored ancestry from European Mesolithic hunter gatherers (WHGs) to varying extents, reflecting admixture between ENFs and WHGs. However, the timing and other details of this process are still imperfectly understood. In this report, we provide a bioarchaeological analysis of three individuals interred at the Brunn 2 site of the Brunn am Gebirge-Wolfholz archeological complex, one of the oldest LBK sites in central Europe. Two of the individuals had a mixture of WHG-related and ANF-related ancestry, one of them with approximately 50% of each, while the third individual had approximately all ANF-related ancestry. Stable carbon and nitrogen isotope ratios for all three individuals were within the range of variation reflecting diets of other Neolithic agrarian populations. Strontium isotope analysis revealed that the ~50% WHG-ANF individual was non-local to the Brunn 2 area. Overall, our data indicate interbreeding between incoming farmers, whose ancestors ultimately came from western Anatolia, and local HGs, starting within the first few generations of the arrival of the former in central Europe, as well as highlighting the integrative nature and composition of the early LBK communities.

A 5700 year-old human genome and oral microbiome from chewed birch pitch

The rise of ancient genomics has revolutionised our understanding of human prehistory but this work depends on the availability of suitable samples. Here we present a complete ancient human genome and oral microbiome sequenced from a 5700 year-old piece of chewed birch pitch from Denmark. We sequence the human genome to an average depth of 2.3× and find that the individual who chewed the pitch was female and that she was genetically more closely related to western hunter-gatherers from mainland Europe than hunter-gatherers from central Scandinavia. We also find that she likely had dark skin, dark brown hair and blue eyes. In addition, we identify DNA fragments from several bacterial and viral taxa, including Epstein-Barr virus, as well as animal and plant DNA, which may have derived from a recent meal. The results highlight the potential of chewed birch pitch as a source of ancient DNA.

Human mitochondrial DNA lineages in Iron-Age Fennoscandia suggest incipient admixture and eastern introduction of farming-related maternal ancestry

Human ancient DNA studies have revealed high mobility in Europe’s past, and have helped to decode the human history on the Eurasian continent. Northeastern Europe, especially north of the Baltic Sea, however, remains less well understood largely due to the lack of preserved human remains. Finland, with a divergent population history from most of Europe, offers a unique perspective to hunter-gatherer way of life, but thus far genetic information on prehistoric human groups in Finland is nearly absent. Here we report 103 complete ancient mitochondrial genomes from human remains dated to AD 300–1800, and explore mtDNA diversity associated with hunter-gatherers and Neolithic farmers. The results indicate largely unadmixed mtDNA pools of differing ancestries from Iron-Age on, suggesting a rather late genetic shift from hunter-gatherers towards farmers in North-East Europe. Furthermore, the data suggest eastern introduction of farmer-related haplogroups into Finland, contradicting contemporary genetic patterns in Finns.

Shifts in the Genetic Landscape of the Western Eurasian Steppe Associated with the Beginning and End of the Scythian Dominance

The Early Iron Age nomadic Scythians have been described as a confederation of tribes of different origins, based on ancient DNA evidence [1-3]. It is still unclear how much of the Scythian dominance in the Eurasian Steppe was due to movements of people and how much reflected cultural diffusion and elite dominance. We present new whole-genome sequences of 31 ancient Western and Eastern Steppe individuals, including Scythians as well as samples pre- and postdating them, allowing us to set the Scythians in a temporal context (in the Western, i.e., Ponto-Caspian Steppe). We detect an increase of eastern (Altaian) affinity along with a decrease in eastern hunter-gatherer (EHG) ancestry in the Early Iron Age Ponto-Caspian gene pool at the start of the Scythian dominance. On the other hand, samples of the Chernyakhiv culture postdating the Scythians in Ukraine have a significantly higher proportion of Near Eastern ancestry than other samples of this study. Our results agree with the Gothic source of the Chernyakhiv culture and support the hypothesis that the Scythian dominance did involve a demic component.

Mitochondrial DNA, a Powerful Tool to Decipher Ancient Human Civilization from Domestication to Music, and to Uncover Historical Murder Cases

Mitochondria are unique organelles carrying their own genetic material, independent from that in the nucleus. This review will discuss the nature of mitochondrial DNA (mtDNA) and its levels in the cell, which are the key elements to consider when trying to achieve molecular identification in ancient and degraded samples. mtDNA sequence analysis has been appropriately validated and is a consistent molecular target for the examination of biological evidence encountered in forensic cases—and profiling, in certain conditions—especially for burnt bodies and degraded samples of all types. Exceptional cases and samples will be discussed in this review, such as mtDNA from leather in Beethoven’s grand piano, mtDNA in mummies, and solving famous historical criminal cases. In addition, this review will be discussing the use of ancient mtDNA to understand past human diet, to trace historical civilizations and ancient trade routes, and to uncover geographical domestication origins and lineage relationships. In each topic, we will present the power of mtDNA and how, in many cases, no nuclear DNA was left, leaving mitochondrial DNA analysis as a powerful alternative. Exploring this powerful tool further will be extremely useful to modern science and researchers, due to its capabilities in providing us with previously unattainable knowledge.

Ancient human mitochondrial genomes from Bronze Age Bulgaria: new insights into the genetic history of Thracians

One of the best documented Indo-European civilizations that inhabited Bulgaria is the Thracians, who lasted for more than five millennia and whose origin and relationships with other past and present-day populations are debated among researchers. Here we report 25 new complete mitochondrial genomes of ancient individuals coming from three necropolises located in different regions of Bulgaria – Shekerdja mogila, Gabrova mogila and Bereketska mogila – dated to II-III millennium BC. The identified mtDNA haplogroup composition reflects the mitochondrial variability of Western Eurasia. In particular, within the ancient Eurasian genetic landscape, Thracians locate in an intermediate position between Early Neolithic farmers and Late Neolithic-Bronze Age steppe pastoralists, supporting the scenario that the Balkan region has been a link between Eastern Europe and the Mediterranean since the prehistoric time. Spatial Principal Component Analysis (sPCA) performed on Thracian and modern mtDNA sequences, confirms the pattern highlighted on ancient populations, overall indicating that the maternal gene pool of Thracians reflects their central geographical position at the gateway of Europe.

Late Pleistocene human genome suggests a local origin for the first farmers of central Anatolia

Anatolia was home to some of the earliest farming communities. It has been long debated whether a migration of farming groups introduced agriculture to central Anatolia. Here, we report the first genome-wide data from a 15,000-year-old Anatolian hunter-gatherer and from seven Anatolian and Levantine early farmers. We find high genetic continuity (~80–90%) between the hunter-gatherers and early farmers of Anatolia and detect two distinct incoming ancestries: an early Iranian/Caucasus related one and a later one linked to the ancient Levant. Finally, we observe a genetic link between southern Europe and the Near East predating 15,000 years ago. Our results suggest a limited role of human migration in the emergence of agriculture in central Anatolia.

Central Anatolia harbored some of the earliest farming societies outside the Fertile Crescent of the Near East. Here, the authors report and analyze genome-wide data from a 15,000-year-old Anatolian hunter-gatherer and from seven Anatolian and Levantine early farmers, and suggest high genetic continuity between the hunter-gatherers and early farmers of Anatolia.

Ancient Mitochondrial Genomes Reveal the Absence of Maternal Kinship in the Burials of Çatalhöyük People and Their Genetic Affinities

Çatalhöyük is one of the most widely recognized and extensively researched Neolithic settlements. The site has been used to discuss a wide range of aspects associated with the spread of the Neolithic lifestyle and the social organization of Neolithic societies. Here, we address both topics using newly generated mitochondrial genomes, obtained by direct sequencing and capture-based enrichment of genomic libraries, for a group of individuals buried under a cluster of neighboring houses from the classical layer of the site’s occupation. Our data suggests a lack of maternal kinship between individuals interred under the floors of Çatalhöyük buildings. The findings could potentially be explained either by a high variability of maternal lineages within a larger kin group, or alternatively, an intentional selection of individuals for burial based on factors other than biological kinship. Our population analyses shows that Neolithic Central Anatolian groups, including Çatalhöyük, share the closest affinity with the population from the Marmara Region and are, in contrast, set further apart from the Levantine populations. Our findings support the hypothesis about the emergence and the direction of spread of the Neolithic within Anatolian Peninsula and beyond, emphasizing a significant role of Central Anatolia in this process.

Bayesian estimation of partial population continuity using ancient DNA and spatially explicit simulations

The retrieval of ancient DNA from osteological material provides direct evidence of human genetic diversity in the past. Ancient DNA samples are often used to investigate whether there was population continuity in the settlement history of an area. Methods based on the serial coalescent algorithm have been developed to test whether the population continuity hypothesis can be statistically rejected by analysing DNA samples from the same region but of different ages. Rejection of this hypothesis is indicative of a large genetic shift, possibly due to immigration occurring between two sampling times. However, this approach is only able to reject a model of full continuity model (a total absence of genetic input from outside), but admixture between local and immigrant populations may lead to partial continuity. We have recently developed a method to test for population continuity that explicitly considers the spatial and temporal dynamics of populations. Here, we extended this approach to estimate the proportion of genetic continuity between two populations, using ancient genetic samples. We applied our original approach to the question of the Neolithic transition in Central Europe. Our results confirmed the rejection of full continuity, but our approach represents an important step forward by estimating the relative contribution of immigrant farmers and of local hunter-gatherers to the final Central European Neolithic genetic pool. Furthermore, we show that a substantial proportion of genes brought by the farmers in this region were assimilated from other hunter-gatherer populations along the way from Anatolia, which was not detectable by previous continuity tests. Our approach is also able to jointly estimate demographic parameters, as we show here by finding both low density and low migration rate for pre-Neolithic hunter-gatherers. It provides a useful tool for the analysis of the numerous ancient DNA data sets that are currently being produced for many different species.

The female ancestor's tale: Long-term matrilineal continuity in a nonisolated region of Tuscany

OBJECTIVES

With the advent of ancient DNA analyses, it has been possible to disentangle the contribution of ancient populations to the genetic pool of the modern inhabitants of many regions. Reconstructing the maternal ancestry has often highlighted genetic continuity over several millennia, but almost always in isolated areas. Here we analyze North-western Tuscany, a region that was a corridor of exchanges between Central Italy and the Western Mediterranean coast.

MATERIALS AND METHODS

We newly obtained mitochondrial HVRI sequences from 28 individuals, and after gathering published data, we collected genetic information for 119 individuals from the region. Those span five periods during the last 5,000 years: Prehistory, Etruscan age, Roman age, Renaissance, and Present-day. We used serial coalescent simulations in an approximate Bayesian computation framework to test for continuity between the mentioned groups.

RESULTS

Our analyses always favor continuity over discontinuity for all groups considered, with the Etruscans being part of the genealogy. Moreover, the posterior distributions of the parameters support very small female effective population sizes.

CONCLUSIONS

The observed signals of long-term genetic continuity and isolation are in contrast with the history of the region, conquered several times (Etruscans, Romans, Lombards, and French). While the Etruscans appear as a local population, intermediate between the prehistoric and the other samples, we suggest that the other conquerors-arriving from far-had a consistent social or sex bias, hence only marginally affecting the maternal lineages. At the same time, our results show that long-term genealogical continuity is not necessarily linked to geographical isolation.

Ancient Genomics of Modern Humans: The First Decade

The first decade of ancient genomics has revolutionized the study of human prehistory and evolution. We review new insights based on prehistoric modern human genomes, including greatly increased resolution of the timing and structure of the out-of-Africa expansion, the diversification of present-day non-African populations, and the earliest expansions of those populations into Eurasia and America. Prehistoric genomes now document population transformations on every inhabited continent—in particular the effect of agricultural expansions in Africa, Europe, and Oceania—and record a history of natural selection that shapes present-day phenotypic diversity. Despite these advances, much remains unknown, in particular about the genomic histories of Asia (the most populous continent) and Africa (the continent that contains the most genetic diversity). Ancient genomes from these and other regions, integrated with a growing understanding of the genomic basis of human phenotypic diversity, will be in focus during the next decade of research in the field.

Mitochondrial variability in the Mediterranean area: a complex stage for human migrations

CONTEXT

The Mediterranean area has always played a significant role in human dispersal due to the large number of migratory events contributing to shape the cultural features and the genetic pool of its populations.

OBJECTIVE

This paper aims to review and diachronically describe the mitogenome variability in the Mediterranean population and the main demic diffusions that occurred in this area over time.

METHODS

Frequency distributions of the leading mitochondrial haplogroups have been geographically and chronologically evaluated. The variability of U5b and K lineages has been focussed to broaden the knowledge of their genetic histories.

RESULTS

The mitochondrial genetic makeup of Palaeolithic hunter-gatherers is poorly defined within the extant Mediterranean populations, since only a few traces of their genetic contribution are still detectable. The Neolithic lineages are more represented, suggesting that the Neolithic revolution had a marked effect on the peopling of the Mediterranean area. The largest effect, however, was provided by historical migrations.

CONCLUSION

Although the mitogenome variability has been widely used to try and clarify the evolution of the Mediterranean genetic makeup throughout almost 50 000 years, it is necessary to collect whole genome data on both extinct and extant populations from this area to fully reconstruct and interpret the impact of multiple migratory waves and their cultural and genetic consequences on the structure of the Mediterranean populations.

The importance of fine-scale studies for integrating paleogenomics and archaeology

There has been an undercurrent of intellectual tension between geneticists studying human population history and archaeologists for almost 40 years. The rapid development of paleogenomics, with geneticists working on the very material discovered by archaeologists, appears to have recently heightened this tension. The relationship between these two fields thus far has largely been of a multidisciplinary nature, with archaeologists providing the raw materials for sequencing, as well as a scaffold of hypotheses based on interpretation of archaeological cultures from which the geneticists can ground their inferences from the genomic data. Much of this work has taken place in the context of western Eurasia, which is acting as testing ground for the interaction between the disciplines. Perhaps the major finding has not been any particular historical episode, but rather the apparent pervasiveness of migration events, some apparently of substantial scale, over the past ∼5000 years, challenging the prevailing view of archaeology that largely dismissed migration as a driving force of cultural change in the 1960s. However, while the genetic evidence for `migration' is generally statistically sound, the description of these events as structured behaviours is lacking, which, coupled with often over simplistic archaeological definitions, prevents the use of this information by archaeologists for studying the social processes they are interested in. In order to integrate paleogenomics and archaeology in a truly interdisciplinary manner, it will be necessary to focus less on grand narratives over space and time, and instead integrate genomic data with other form of archaeological information at the level of individual communities to understand the internal social dynamics, which can then be connected amongst communities to model migration at a regional level. A smattering of recent studies have begun to follow this approach, resulting in inferences that are not only helping ask questions that are currently relevant to archaeologists, but also potentially opening up new avenues of research.