Population genomic analysis of ancient and modern genomes yields new insights into the genetic ancestry of the Tyrolean Iceman and the genetic structure of Europe

Genetic Diversity Based on Human Y Chromosome Analysis: A Bibliometric Review Between 2014 and 2023

The Y chromosome has gained significant importance in the examination of genetic studies of populations because of its non-recombinant character and its form of uniparental inheritance. This work seeks to offer a comprehensive review of the specialty literature in the field of population genetics, focusing specifically on the analysis of the human Y chromosome using a bibliometric approach and knowledge mapping. This involves establishing worldwide structural networks by identifying the primary research themes, authors, and papers that have had a significant impact on the academic community. The objective is to examine global publications by analyzing citations at both the document and country level. This will involve conducting co-citation analysis for references with a high number of citations, examining bibliographic coupling through journal analysis, analyzing the co-occurrence of keywords, and investigating collaboration between authors from a country perspective. The research papers have been extracted from the Web of Science database. The bibliometric analysis was performed using the Bibliometrix and VOSviewer software tools. The purpose of this article is to serve as a starting point for future research dedicated to the analysis of the diversity of human Y chromosome haplotypes. The objectives of the study were to identify and present the most cited publications and references with the highest number of citations, and to highlight current publications at the national level.

Evolutionary immuno-genetics of endoplasmic reticulum aminopeptidase II (ERAP2)

Endoplasmic reticulum aminopeptidase 2 (ERAP2) is a proteolytic enzyme involved in adaptive immunity. The ERAP2 gene is highly polymorphic and encodes haplotypes that confer resistance against lethal infectious diseases, but also increase the risk for autoimmune disorders. Identifying how ERAP2 influences susceptibility to these traits requires an understanding of the selective pressures that shaped and maintained allelic variation throughout human evolution. Our review discusses the genetic regulation of haplotypes and diversity in naturally occurring ERAP2 allotypes in the global population. We outline how these ERAP2 haplotypes evolved during human history and highlight the presence of Neanderthal DNA sequences in ERAP2 of modern humans. Recent evidence suggests that human adaptation during the last ~10,000 years and historic pandemics left a significant mark on the ERAP2 gene that determines susceptibility to infectious and inflammatory diseases today.

Bioarchaeological and paleogenomic profiling of the unusual Neolithic burial from Grotta di Pietra Sant'Angelo (Calabria, Italy)

The Neolithic burial of Grotta di Pietra Sant'Angelo (CS) represents a unique archaeological finding for the prehistory of Southern Italy. The unusual placement of the inhumation at a rather high altitude and far from inhabited areas, the lack of funerary equipment and the prone deposition of the body find limited similarities in coeval Italian sites. These elements have prompted wider questions on mortuary customs during the prehistory of Southern Italy. This atypical case requires an interdisciplinary approach aimed to build an integrated bioarchaeological profile of the individual. The paleopathological investigation of the skeletal remains revealed the presence of numerous markers that could be associated with craft activities, suggesting possible interpretations of the individual's lifestyle. CT analyses, carried out on the maxillary bones, showed the presence of a peculiar type of dental wear, but also a good density of the bone matrix. Biomolecular and micromorphological analyses of dental calculus highlight the presence of a rich Neolithic-like oral microbiome, the composition of which is consistent with the presence pathologies. Finally, paleogenomic data obtained from the individual were compared with ancient and modern Mediterranean populations, including unpublished high-resolution genome-wide data for 20 modern inhabitants of the nearby village of San Lorenzo Bellizzi, which provided interesting insights into the biodemographic landscape of the Neolithic in Southern Italy.

A Protective HLA Extended Haplotype Outweighs the Major COVID-19 Risk Factor Inherited From Neanderthals in the Sardinian Population

Sardinia has one of the lowest incidences of hospitalization and related mortality in Europe and yet a very high frequency of the Neanderthal risk locus variant on chromosome 3 (rs35044562), considered to be a major risk factor for a severe SARS-CoV-2 disease course. We evaluated 358 SARS-CoV-2 patients and 314 healthy Sardinian controls. One hundred and twenty patients were asymptomatic, 90 were pauci-symptomatic, 108 presented a moderate disease course and 40 were severely ill. All patients were analyzed for the Neanderthal-derived genetic variants reported as being protective (rs1156361) or causative (rs35044562) for severe illness. The β°39 C>T Thalassemia variant (rs11549407), HLA haplotypes, KIR genes, KIRs and their HLA class I ligand combinations were also investigated. Our findings revealed an increased risk for severe disease in Sardinian patients carrying the rs35044562 high risk variant [OR 5.32 (95% CI 2.53 - 12.01), p = 0.000]. Conversely, the protective effect of the HLA-A*02:01, B*18:01, DRB*03:01 three-loci extended haplotype in the Sardinian population was shown to efficiently contrast the high risk of a severe and devastating outcome of the infection predicted for carriers of the Neanderthal locus [OR 15.47 (95% CI 5.8 - 41.0), p < 0.0001]. This result suggests that the balance between risk and protective immunogenetic factors plays an important role in the evolution of COVID-19. A better understanding of these mechanisms may well turn out to be the biggest advantage in the race for the development of more efficient drugs and vaccines.

Circum-Saharan Prehistory through the Lens of mtDNA Diversity

African history has been significantly influenced by the Sahara, which has represented a barrier for migrations of all living beings, including humans. Major exceptions were the gene flow events that took place between North African and sub-Saharan populations during the so-called African Humid Periods, especially in the Early Holocene (11.5 to 5.5 thousand years ago), and more recently in connection with trans-Saharan commercial routes. In this study, we describe mitochondrial DNA (mtDNA) diversity of human populations from both sides of the Sahara Desert, i.e., both from North Africa and the Sahel/Savannah belt. The final dataset of 7213 mtDNA sequences from 134 African populations encompasses 470 newly collected and 6743 previously published samples, which were analyzed using descriptive methods and Bayesian statistics. We completely sequenced 26 mtDNAs from sub-Saharan samples belonging to the Eurasian haplogroup N1. Analyses of these N1 mitogenomes revealed their possible routes to the Sahel, mostly via Bab el-Mandab. Our results indicate that maternal gene flow must have been important in this circum-Saharan space, not only within North Africa and the Sahel/Savannah belt but also between these two regions.

Alignment-free methods for polyploid genomes: Quick and reliable genetic distance estimation

Polyploid genomes pose several inherent challenges to population genetic analyses. While alignment-based methods are fundamentally limited in their applicability to polyploids, alignment-free methods bypass most of these limits. We investigated the use of Mash, a k-mer analysis tool that uses the MinHash method to reduce complexity in large genomic data sets, for basic population genetic analyses of polyploid sequences. We measured the degree to which Mash correctly estimated pairwise genetic distance in simulated haploid and polyploid short-read sequences with various levels of missing data. Mash-based estimates of genetic distance were comparable to alignment-based estimates, and were less impacted by missing data. We also used Mash to analyse publicly available short-read data for three polyploid and one diploid species, then compared Mash results to published results. For both simulated and real data, Mash accurately estimated pairwise genetic differences for polyploids as well as diploids as much as 476 times faster than alignment-based methods, though we found that Mash genetic distance estimates could be biased by per-sample read depth. Mash may be a particularly useful addition to the toolkit of polyploid geneticists for rapid confirmation of alignment-based results and for basic population genetics in reference-free systems or those with only poor-quality sequence data available.

From old markers to next generation: reconstructing the history of the peopling of Sardinia

CONTEXT

For many years the Sardinian population has been the object of numerous studies because of its unique genetic structure. Despite the extreme abundance of papers, various aspects of the peopling and genetic structure of Sardinia still remain uncertain and sometimes controversial.

OBJECTIVE

We reviewed what has emerged from different studies, focussing on some still open questions, such as the origin of Sardinians, their relationship with the Corsican population, and the intra-regional genetic heterogeneity.

METHODS

The various issues have been addressed through the analysis of classical markers, molecular markers and, finally, genomic data through next generation sequencing.

RESULTS AND CONCLUSIONS

Although the most ancient human remains date back to the end of the Palaeolithic, Mesolithic populations brought founding lineages that left evident traces in the modern population. Then, with the Neolithic, the island underwent an important demographic expansion. Subsequently, isolation and genetic drift contributed to maintain a significant genetic heterogeneity, but preserving the overall homogeneity on a regional scale. At the same time, isolation and genetic drift contributed to differentiate Sardinia from Corsica, which saw an important gene flow from the mainland. However, the isolation did not prevent gene flow from the neighbouring populations whose contribution are still recognisable in the genome of Sardinians.

Insights into Punic genetic signatures in the southern necropolis of Tharros (Sardinia)

BACKGROUND

Phoenician and Punic expansions have been protagonists of intense trade networks and settlements in the Mediterranean Sea.

AIMS

The maternal genetic variability of ancient Punic samples from the Sardinian necropolis of Tharros was analysed, with the aim to explore genetic interactions and signatures of past population events.

SUBJECTS AND METHODS

The mtDNA HVS-I and coding region SNPs were analysed in 14 Punic samples and 74 modern individuals from Cabras and Belvì (for which the HVS-II region was also analysed). The results were compared with 5,590 modern Euro-Mediterranean sequences and 127 ancient samples.

RESULTS

While contemporary groups fall within the genetic variability of other modern Sardinians, our Punic samples reveal proximity to present-day North-African and Iberian populations. Furthermore, Cabras and Belvì cluster mainly with pre-Phoenician groups, while samples from Tharros project with other Punic Sardinian individuals.

CONCLUSION

This study provides the first preliminary insights into the population dynamics of the Punic site of Tharros. While the number of currently available samples does not allow definitive investigation of the connection with indigenous Sardinian groups, our results seem to confirm internal migratory phenomena in the central-western Mediterranean and female participation in the Punic mobility.

The genetic and cultural impact of the Steppe migration into Europe

BACKGROUND

During the early 3rd millennium BCE migration from Pontic Steppe, mainly related to Yamnaya culture, has affected European populations both culturally and genetically, however, it has long been debated to what extent this migration was male-driven, and how this replacement process took place which eliminated partially/largely Neolithic male lines over time.

AIM

This paper aims to evaluate the influence of the Steppe migration on European Bronze Age populations by calculating both male and female genetic contributions of the Steppe-related ancestry to the European Bronze Age populations. With this approach, we will be able to clarify the hypotheses on whether it was male-biased migration or not.

SUBJECTS AND METHODS

To evaluate the genetic impact and the proportion of the Steppe-related ancestry to the European Bronze Age populations, we performed PCA and qpAdm analyses by using published genome-wide data. In addition, we quantified male and female genetic contribution into Europe by using the analysis of uniparental markers and the X-chromosome.

RESULTS

The Steppe migration had a considerable impact on the genetic makeup of the Bronze Age European populations. The data suggest that the Steppe-related ancestry arriving into Central Europe was male-driven, dominantly in the Corded Ware culture populations and lesser in the Bell Beaker populations. In fact, there is no evidence that this migration had a significant input on the mitochondrial genetic pool of all European Bronze Age populations.

CONCLUSIONS

Our analyses suggest that the Steppe-related ancestry had genetic impact on mainly Central-Eastern Europe. Moreover, this migration was male-driven for most of the Central European populations belonging to the Corded Ware groups, and to a lesser extent for the Bell Beaker groups.

[The Iceman : Life scenarios and pathological findings from 30 years of research on the glacier mummy "Ötzi"]

The comprehensive investigation of the excellently preserved mummy of Ötzi, the Iceman, and his equipment over the last 30 years has provided a wealth of information about the life and disease of this late Neolithic individual. This research has indicated that his origin was from a local southern Alpine population, that he grew up in the valleys of the Southern Alps, and that he had considerable local mobility. He had well-balanced nutrition with a mixed vegetable and animal diet. He was very mobile in the alpine terrain and of athletic constitution. The Iceman suffered from mild to moderate degenerative joint disease primarily of the right hip joint, slight spondylosis of the cervical and lumbar spine, a minor focal (premature) arteriosclerosis, lung anthracosis and possibly silicosis, previous pleuritic inflammation (possibly of post-specific origin), intestinal infections of the stomach by Helicobacter pylori and Trichuris trichiura worm infestation in the intestines, a mild osteomalacia of cancellous bone, and diverse pathologies of his teeth with dental caries and periodontitis, as well as hair anomalies. The presence of borreliosis is still under debate. As potential remedies, the Iceman carried some anthelmintic substances with him: a birch polypore and an anthelmintic fern. The numerous tattoos may also have had therapeutic effects. Finally, the last days of Ötzi could be reconstructed quite precisely: his gastrointestinal content indicates that the Iceman moved from Alpine heights to a lower location and then again up to the glacier region where he died. During this journey he encountered two attacks: the first, several days before his death, lead to a stabbing wound in his right hand; the second was an arrow hit that wounded the Iceman lethally at his left axilla by laceration of the subclavian artery.

Ancient genomes reveal structural shifts after the arrival of Steppe-related ancestry in the Italian Peninsula

Across Europe, the genetics of the Chalcolithic/Bronze Age transition is increasingly characterized in terms of an influx of Steppe-related ancestry. The effect of this major shift on the genetic structure of populations in the Italian Peninsula remains underexplored. Here, genome-wide shotgun data for 22 individuals from commingled cave and single burials in Northeastern and Central Italy dated between 3200 and 1500 BCE provide the first genomic characterization of Bronze Age individuals (n = 8; 0.001-1.2× coverage) from the central Italian Peninsula, filling a gap in the literature between 1950 and 1500 BCE. Our study confirms a diversity of ancestry components during the Chalcolithic and the arrival of Steppe-related ancestry in the central Italian Peninsula as early as 1600 BCE, with this ancestry component increasing through time. We detect close patrilineal kinship in the burial patterns of Chalcolithic commingled cave burials and a shift away from this in the Bronze Age (2200-900 BCE) along with lowered runs of homozygosity, which may reflect larger changes in population structure. Finally, we find no evidence that the arrival of Steppe-related ancestry in Central Italy directly led to changes in frequency of 115 phenotypes present in the dataset, rather that the post-Roman Imperial period had a stronger influence, particularly on the frequency of variants associated with protection against Hansen's disease (leprosy). Our study provides a closer look at local dynamics of demography and phenotypic shifts as they occurred as part of a broader phenomenon of widespread admixture during the Chalcolithic/Bronze Age transition.

Human population dynamics and Yersinia pestis in ancient northeast Asia

We present genome-wide data from 40 individuals dating to c.16,900 to 550 years ago in northeast Asia. We describe hitherto unknown gene flow and admixture events in the region, revealing a complex population history. While populations east of Lake Baikal remained relatively stable from the Mesolithic to the Bronze Age, those from Yakutia and west of Lake Baikal witnessed major population transformations, from the Late Upper Paleolithic to the Neolithic, and during the Bronze Age, respectively. We further locate the Asian ancestors of Paleo-Inuits, using direct genetic evidence. Last, we report the most northeastern ancient occurrence of the plague-related bacterium, Yersinia pestis Our findings indicate the highly connected and dynamic nature of northeast Asia populations throughout the Holocene.

Population genetics of wild Macaca fascicularis with low-coverage shotgun sequencing of museum specimens

OBJECTIVES

Long-tailed macaques (Macaca fascicularis) are widely distributed throughout the mainland and islands of Southeast Asia, making them a useful model for understanding the complex biogeographical history resulting from drastic changes in sea levels throughout the Pleistocene. Past studies based on mitochondrial genomes (mitogenomes) of long-tailed macaque museum specimens have traced their colonization patterns throughout the archipelago, but mitogenomes trace only the maternal history. Here, our objectives were to trace phylogeographic patterns of long-tailed macaques using low-coverage nuclear DNA (nDNA) data from museum specimens.

METHODS

We performed population genetic analyses and phylogenetic reconstruction on nuclear single nucleotide polymorphisms (SNPs) from shotgun sequencing of 75 long-tailed macaque museum specimens from localities throughout Southeast Asia.

RESULTS

We show that shotgun sequencing of museum specimens yields sufficient genome coverage (average ~1.7%) for reconstructing population relationships using SNP data. Contrary to expectations of divergent results between nuclear and mitochondrial genomes for a female philopatric species, phylogeographical patterns based on nuclear SNPs proved to be closely similar to those found using mitogenomes. In particular, population genetic analyses and phylogenetic reconstruction from the nDNA identify two major clades within M. fascicularis: Clade A includes all individuals from the mainland along with individuals from northern Sumatra, while Clade B consists of the remaining island-living individuals, including those from southern Sumatra.

CONCLUSIONS

Overall, we demonstrate that low-coverage sequencing of nDNA from museum specimens provides enough data for examining broad phylogeographic patterns, although greater genome coverage and sequencing depth would be needed to distinguish between very closely related populations, such as those throughout the Philippines.

Sahelian pastoralism from the perspective of variants associated with lactase persistence

OBJECTIVES

Archeological evidence shows that first nomadic pastoralists came to the African Sahel from northeastern Sahara, where milking is reported by ~7.5 ka. A second wave of pastoralists arrived with the expansion of Arabic tribes in 7th-14th century CE. All Sahelian pastoralists depend on milk production but genetic diversity underlying their lactase persistence (LP) is poorly understood.

MATERIALS AND METHODS

We investigated SNP variants associated with LP in 1,241 individuals from 29 mostly pastoralist populations in the Sahel. Then, we analyzed six SNPs in the neighboring fragment (419 kb) in the Fulani and Tuareg with the -13910*T mutation, reconstructed haplotypes, and calculated expansion age and growth rate of this variant.

RESULTS

Our results reveal a geographic localization of two different LP variants in the Sahel: -13910*T west of Lake Chad (Fulani and Tuareg pastoralists) and -13915*G east of there (mostly Arabic-speaking pastoralists). We show that -13910*T has a more diversified haplotype background among the Fulani than among the Tuareg and that the age estimate for expansion of this variant among the Fulani (~8.5 ka) corresponds to introduction of cattle to the area.

CONCLUSIONS

This is the first study showing that the "Eurasian" LP allele -13910*T is widespread both in northern Europe and in the Sahel; however, it is limited to pastoralists in the Sahel. Since the Fulani haplotype with -13910*T is shared with contemporary Eurasians, its origin could be in a region encompassing the Near East and northeastern Africa in a population ancestral to both Saharan pastoralists and European farmers.

Genomic history of the Italian population recapitulates key evolutionary dynamics of both Continental and Southern Europeans

BACKGROUND

The cline of human genetic diversity observable across Europe is recapitulated at a micro-geographic scale by variation within the Italian population. Besides resulting from extensive gene flow, this might be ascribable also to local adaptations to diverse ecological contexts evolved by people who anciently spread along the Italian Peninsula. Dissecting the evolutionary history of the ancestors of present-day Italians may thus improve the understanding of demographic and biological processes that contributed to shape the gene pool of European populations. However, previous SNP array-based studies failed to investigate the full spectrum of Italian variation, generally neglecting low-frequency genetic variants and examining a limited set of small effect size alleles, which may represent important determinants of population structure and complex adaptive traits. To overcome these issues, we analyzed 38 high-coverage whole-genome sequences representative of population clusters at the opposite ends of the cline of Italian variation, along with a large panel of modern and ancient Euro-Mediterranean genomes.

RESULTS

We provided evidence for the early divergence of Italian groups dating back to the Late Glacial and for Neolithic and distinct Bronze Age migrations having further differentiated their gene pools. We inferred adaptive evolution at insulin-related loci in people from Italian regions with a temperate climate, while possible adaptations to pathogens and ultraviolet radiation were observed in Mediterranean Italians. Some of these adaptive events may also have secondarily modulated population disease or longevity predisposition.

CONCLUSIONS

We disentangled the contribution of multiple migratory and adaptive events in shaping the heterogeneous Italian genomic background, which exemplify population dynamics and gene-environment interactions that played significant roles also in the formation of the Continental and Southern European genomic landscapes.

The spatiotemporal spread of human migrations during the European Holocene

The European continent was subject to two major migrations of peoples during the Holocene: the northwestward movement of Anatolian farmer populations during the Neolithic and the westward movement of Yamnaya steppe peoples during the Bronze Age. These movements changed the genetic composition of the continent's inhabitants. The Holocene was also characterized by major changes in vegetation composition, which altered the environment occupied by the original hunter-gatherer populations. We aim to test to what extent vegetation change through time is associated with changes in population composition as a consequence of these migrations, or with changes in climate. Using ancient DNA in combination with geostatistical techniques, we produce detailed maps of ancient population movements, which allow us to visualize how these migrations unfolded through time and space. We find that the spread of Neolithic farmer ancestry had a two-pronged wavefront, in agreement with similar findings on the cultural spread of farming from radiocarbon-dated archaeological sites. This movement, however, did not have a strong association with changes in the vegetational landscape. In contrast, the Yamnaya migration speed was at least twice as fast and coincided with a reduction in the amount of broad-leaf forest and an increase in the amount of pasture and natural grasslands in the continent. We demonstrate the utility of integrating ancient genomes with archaeometric datasets in a spatiotemporal statistical framework, which we foresee will enable future studies of ancient populations' movements, and their putative effects on local fauna and flora.

Corded Ware cultural complexity uncovered using genomic and isotopic analysis from south-eastern Poland

During the Final Eneolithic the Corded Ware Complex (CWC) emerges, chiefly identified by its specific burial rites. This complex spanned most of central Europe and exhibits demographic and cultural associations to the Yamnaya culture. To study the genetic structure and kin relations in CWC communities, we sequenced the genomes of 19 individuals located in the heartland of the CWC complex region, south-eastern Poland. Whole genome sequence and strontium isotope data allowed us to investigate genetic ancestry, admixture, kinship and mobility. The analysis showed a unique pattern, not detected in other parts of Poland; maternally the individuals are linked to earlier Neolithic lineages, whereas on the paternal side a Steppe ancestry is clearly visible. We identified three cases of kinship. Of these two were between individuals buried in double graves. Interestingly, we identified kinship between a local and a non-local individual thus discovering a novel, previously unknown burial custom.

Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia

The island of Sardinia has been of particular interest to geneticists for decades. The current model for Sardinia's genetic history describes the island as harboring a founder population that was established largely from the Neolithic peoples of southern Europe and remained isolated from later Bronze Age expansions on the mainland. To evaluate this model, we generate genome-wide ancient DNA data for 70 individuals from 21 Sardinian archaeological sites spanning the Middle Neolithic through the Medieval period. The earliest individuals show a strong affinity to western Mediterranean Neolithic populations, followed by an extended period of genetic continuity on the island through the Nuragic period (second millennium BCE). Beginning with individuals from Phoenician/Punic sites (first millennium BCE), we observe spatially-varying signals of admixture with sources principally from the eastern and northern Mediterranean. Overall, our analysis sheds light on the genetic history of Sardinia, revealing how relationships to mainland populations shifted over time.

The spread of steppe and Iranian-related ancestry in the islands of the western Mediterranean

Steppe-pastoralist-related ancestry reached Central Europe by at least 2500 BC, whereas Iranian farmer-related ancestry was present in Aegean Europe by at least 1900 BC. However, the spread of these ancestries into the western Mediterranean, where they have contributed to many populations that live today, remains poorly understood. Here, we generated genome-wide ancient-DNA data from the Balearic Islands, Sicily and Sardinia, increasing the number of individuals with reported data from 5 to 66. The oldest individual from the Balearic Islands (~2400 BC) carried ancestry from steppe pastoralists that probably derived from west-to-east migration from Iberia, although two later Balearic individuals had less ancestry from steppe pastoralists. In Sicily, steppe pastoralist ancestry arrived by ~2200 BC, in part from Iberia; Iranian-related ancestry arrived by the mid-second millennium BC, contemporary to its previously documented spread to the Aegean; and there was large-scale population replacement after the Bronze Age. In Sardinia, nearly all ancestry derived from the island's early farmers until the first millennium BC, with the exception of an outlier from the third millennium BC, who had primarily North African ancestry and who-along with an approximately contemporary Iberian-documents widespread Africa-to-Europe gene flow in the Chalcolithic. Major immigration into Sardinia began in the first millennium BC and, at present, no more than 56-62% of Sardinian ancestry is from its first farmers. This value is lower than previous estimates, highlighting that Sardinia, similar to every other region in Europe, has been a stage for major movement and mixtures of people.

Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case

Many anthropological, linguistic, genetic and genomic analyses have been carried out to evaluate the potential impact that evolutionary forces had in shaping the present-day Sardinian gene pool, the main outlier in the genetic landscape of Europe. However, due to the homogenizing effect of internal movements, which have intensified over the past fifty years, only partial information has been obtained about the main demographic events. To overcome this limitation, we analyzed the male-specific region of the Y chromosome in three population samples obtained by reallocating a large number of Sardinian subjects to the place of origin of their monophyletic surnames, which are paternally transmitted through generations in most of the populations, much like the Y chromosome. Three Y-chromosome founding lineages, G2-L91, I2-M26 and R1b-V88, were identified as strongly contributing to the definition of the outlying position of Sardinians in the European genetic context and marking a significant differentiation within the island. The present distribution of these lineages does not always mirror that detected in ancient DNAs. Our results show that the analysis of the Y-chromosome gene pool coupled with a sampling method based on the origin of the family name, is an efficient approach to unravelling past heterogeneity, often hidden by recent movements, in the gene pool of modern populations. Furthermore, the reconstruction and comparison of past genetic isolates represent a starting point to better assess the genetic information deriving from the increasing number of available ancient DNA samples.

EGFR, KRAS, BRAF, ALK, and cMET genetic alterations in 1440 Sardinian patients with lung adenocarcinoma

BACKGROUND

Lung cancer is one of the most incident neoplastic diseases, and a leading cause of death for cancer worldwide. Knowledge of the incidence of druggable genetic alterations, their correlation with clinical and pathological features of the disease, and their interplay in cases of co-occurrence is crucial for selecting the best therapeutic strategies of patients with non-small cell lung cancer. In this real-life study, we describe the molecular epidemiology of genetic alterations in five driver genes and their correlations with the demographic and clinical characteristics of Sardinian patients with lung adenocarcinoma.

METHODS

Data from 1440 consecutive Sardinian patients with a histologically proven diagnosis of lung adenocarcinoma from January 2011 through July 2016 were prospectively investigated. EGFR mutation analysis was performed for all of them, while KRAS and BRAF mutations were searched in 1047 cases; ALK alterations were determined with fluorescence in situ hybridization in 899 cases, and cMET amplifications in 788 cases.

RESULTS

KRAS mutations were the most common genetic alterations involving 22.1% of the cases and being mutually exclusive with the EGFR mutations, which were found in 12.6% of them. BRAF mutations, ALK rearrangements, and cMET amplifications were detected in 3.2, 5.3, and 2.1% of the cases, respectively. Concomitant mutations were detected only in a few cases.

CONCLUSIONS

Almost all the genetic alterations studied showed a similar incidence in comparison with other Caucasian populations. Concomitant mutations were rare, and they probably have a scarce impact on the clinical management of Sardinians with lung adenocarcinoma. The low incidence of concomitant cMET amplifications at diagnosis suggests that these alterations are acquired in subsequent phases of the disease, often during treatment with TKIs.

The Current Situation of the Tyrolean Iceman

The Tyrolean Iceman, commonly known as Ötzi, is the world's oldest glacier mummy and one of the best investigated ancient human remains in the world. Since the discovery of the 5,300-year-old Copper Age individual in 1991, in a glacier in the Eastern Italian Alps, a variety of morphological, biochemical, and molecular analyses have been performed that revealed important insights into his origin, his life habits, and the circumstances surrounding his demise. In more recent research, the mummy was subjected to cutting-edge modern research methodologies currently focusing on high-throughput sequence analysis of ancient biomolecules (DNA, proteins, lipids) that are still preserved in the mummified tissues. This application of innovative "-omics" technologies revealed novel insights on the ancestry, disease predisposition, diet, and the presence of pathogens in the glacier mummy. In this review, the most important and actual results of the molecular studies will be highlighted.

Possible evidence for care and treatment in the Tyrolean Iceman

The Tyrolean Iceman is the world's oldest glacier mummy. He was found in September 1991 in the Italian part of the Ötztal Alps. Since his discovery a variety of morphological, radiological and molecular analyses have been performed that revealed detailed insights into his state of health. Despite the various pathological conditions found in the Iceman, little is known about possible forms of care and treatment during the Copper Age in Northern Italy. A possible approach to this topic is the presence of tattoos on the mummified body. In previous work, it was already believed that the tattoos were administered as a kind of treatment for his lower back pain and degenerative joint disease of his knees, hip and wrist. In other studies, the tattoos of the Iceman have been related to an early form of acupuncture. We carefully re-evaluated the various health issues of the Iceman, including joint diseases, gastrointestinal problems and arterial calcifications and compared them to the location and number of tattoos. Together with the finding of medically effective fungi and plants, such as the birch polypore or fern in his equipment and intestines, we suggest that care and treatment was already common during the Iceman's time.

The genetic prehistory of the Andean highlands 7000 years BP though European contact

The peopling of the Andean highlands above 2500 m in elevation was a complex process that included cultural, biological, and genetic adaptations. Here, we present a time series of ancient whole genomes from the Andes of Peru, dating back to 7000 calendar years before the present (BP), and compare them to 42 new genome-wide genetic variation datasets from both highland and lowland populations. We infer three significant features: a split between low- and high-elevation populations that occurred between 9200 and 8200 BP; a population collapse after European contact that is significantly more severe in South American lowlanders than in highland populations; and evidence for positive selection at genetic loci related to starch digestion and plausibly pathogen resistance after European contact. We do not find selective sweep signals related to known components of the human hypoxia response, which may suggest more complex modes of genetic adaptation to high altitude.

Genomic history of the Sardinian population

The population of the Mediterranean island of Sardinia has made important contributions to genome-wide association studies of complex disease traits and, based on ancient DNA (aDNA) studies of mainland Europe, Sardinia is hypothesized to be a unique refuge for early Neolithic ancestry. To provide new insights on the genetic history of this flagship population, we analyzed 3,514 whole-genome sequenced individuals from Sardinia. We find Sardinian samples show elevated levels of shared ancestry with Basque individuals, especially samples from the more historically isolated regions of Sardinia. Our analysis also uniquely illuminates how levels of genetic similarity with mainland aDNA samples varies subtly across the island. Together, our results indicate within-island sub-structure and sex-biased processes have substantially impacted the genetic history of Sardinia. These results give new insight to the demography of ancestral Sardinians and help further the understanding of sharing of disease risk alleles between Sardinia and mainland populations.

Four millennia of Iberian biomolecular prehistory illustrate the impact of prehistoric migrations at the far end of Eurasia

Population genomic studies of ancient human remains have shown how modern-day European population structure has been shaped by a number of prehistoric migrations. The Neolithization of Europe has been associated with large-scale migrations from Anatolia, which was followed by migrations of herders from the Pontic steppe at the onset of the Bronze Age. Southwestern Europe was one of the last parts of the continent reached by these migrations, and modern-day populations from this region show intriguing similarities to the initial Neolithic migrants. Partly due to climatic conditions that are unfavorable for DNA preservation, regional studies on the Mediterranean remain challenging. Here, we present genome-wide sequence data from 13 individuals combined with stable isotope analysis from the north and south of Iberia covering a four-millennial temporal transect (7,500-3,500 BP). Early Iberian farmers and Early Central European farmers exhibit significant genetic differences, suggesting two independent fronts of the Neolithic expansion. The first Neolithic migrants that arrived in Iberia had low levels of genetic diversity, potentially reflecting a small number of individuals; this diversity gradually increased over time from mixing with local hunter-gatherers and potential population expansion. The impact of post-Neolithic migrations on Iberia was much smaller than for the rest of the continent, showing little external influence from the Neolithic to the Bronze Age. Paleodietary reconstruction shows that these populations have a remarkable degree of dietary homogeneity across space and time, suggesting a strong reliance on terrestrial food resources despite changing culture and genetic make-up.

Analysis of Human Sequence Data Reveals Two Pulses of Archaic Denisovan Admixture

Anatomically modern humans interbred with Neanderthals and with a related archaic population known as Denisovans. Genomes of several Neanderthals and one Denisovan have been sequenced, and these reference genomes have been used to detect introgressed genetic material in present-day human genomes. Segments of introgression also can be detected without use of reference genomes, and doing so can be advantageous for finding introgressed segments that are less closely related to the sequenced archaic genomes. We apply a new reference-free method for detecting archaic introgression to 5,639 whole-genome sequences from Eurasia and Oceania. We find Denisovan ancestry in populations from East and South Asia and Papuans. Denisovan ancestry comprises two components with differing similarity to the sequenced Altai Denisovan individual. This indicates that at least two distinct instances of Denisovan admixture into modern humans occurred, involving Denisovan populations that had different levels of relatedness to the sequenced Altai Denisovan. VIDEO ABSTRACT.

Reconciling evidence from ancient and contemporary genomes: a major source for the European Neolithic within Mediterranean Europe

Important gaps remain in our understanding of the spread of farming into Europe, due partly to apparent contradictions between studies of contemporary genetic variation and ancient DNA. It seems clear that farming was introduced into central, northern, and eastern Europe from the south by pioneer colonization. It is often argued that these dispersals originated in the Near East, where the potential source genetic pool resembles that of the early European farmers, but clear ancient DNA evidence from Mediterranean Europe is lacking, and there are suggestions that Mediterranean Europe may have resembled the Near East more than the rest of Europe in the Mesolithic. Here, we test this proposal by dating mitogenome founder lineages from the Near East in different regions of Europe. We find that whereas the lineages date mainly to the Neolithic in central Europe and Iberia, they largely date to the Late Glacial period in central/eastern Mediterranean Europe. This supports a scenario in which the genetic pool of Mediterranean Europe was partly a result of Late Glacial expansions from a Near Eastern refuge, and that this formed an important source pool for subsequent Neolithic expansions into the rest of Europe.

Allele and haplotype diversity of 12 X-STRs in Sardinia

The analysis of clusters of tightly linked X-chromosome short tandem repeat (STR) markers can assist the interpretation of complex kinship cases. However, when linkage disequilibrium (LD) is present in the population of origin of tested individuals, haplotype rather than allele frequencies should be used in likelihood calculations. The diversity of twelve X-STRs arranged in four linkage groups (I: DXS10148-DXS10135-DXS8378; II: DXS7132-DXS10079-DXS10074; III: DXS10103-HPRTB-DXS10101; IV: DXS10146-DXS10134-DXS7423) was tested in a Sardinian population sample (n=516) including three open populations from the Northern, Central and Southern part of the island, and three isolates (Benetutti, Desulo, Carloforte). Evidence of LD was detected in Sardinia within each linkage group. Significant differences in haplotype and allele frequency distribution of X-STR markers was seen between isolates and open populations, which on the contrary appeared highly homogeneous. The percentage of Sardinian haplotypes previously unobserved in a similar dataset compiled for the Italian population was: 76.3% (linkage group I), 61.3% (linkage group II), 54.1% (linkage group III), 58.9% (linkage group IV). Significant pairwise genetic differences were seen between mainland Italy, the three Sardinian isolates, and the open population of Southern Sardinia. The study confirms the presence of high levels and complex patterns of LD along the X chromosome in Sardinia, and provides population-specific haplotype data for biostatistical evaluation in kinship testing.

The Eastern side of the Westernmost Europeans: Insights from subclades within Y-chromosome haplogroup J-M304

OBJECTIVES

We examined internal lineages and haplotype diversity in Portuguese samples belonging to J-M304 to improve the spatial and temporal understanding of the introduction of this haplogroup in Iberia, using the available knowledge about the phylogeography of its main branches, J1-M267 and J2-M172.

METHODS

A total of 110 males of Portuguese descent were analyzed for 17 Y-chromosome bi-allelic markers and seven Y-chromosome short tandem repeats (Y-STR) loci.

RESULTS

Among J1-M267 individuals (n = 36), five different sub-haplogroups were identified, with the most common being J1a2b2-L147.1 (∼72%), which encompassed the majority of representatives of the J1a2b-P58 subclade. One sample belonged to the rare J1a1-M365.1 lineage and presented a core Y-STR haplotype consistent with the Iberian settlement during the fifth century by the Alans, a people of Iranian heritage. The analysis of J2-M172 Portuguese males (n = 74) enabled the detection of the two main subclades at very dissimilar frequencies, J2a-M410 (∼80%) and J2b-M12 (∼20%), among which the most common branches were J2a1(xJ2a1b,h)-L26 (22.9%), J2a1b(xJ2a1b1)-M67 (20.3%), J2a1h-L24 (27%), and J2b2-M241 (20.3%).

CONCLUSIONS

While previous inferences based on modern haplogroup J Y-chromosomes implicated a main Neolithic dissemination, here we propose a later arrival of J lineages into Iberia using a combination of novel Portuguese Y-chromosomal data and recent evidence from ancient DNA. Our analysis suggests that a substantial tranche of J1-M267 lineages was likely carried into the Iberian Peninsula as a consequence of the trans-Mediterranean contacts during the first millennium BC, while most of the J2-M172 lineages may be associated with post-Neolithic population movements within Europe.

Genetic Ancestry of Rapanui before and after European Contact

The origins and lifeways of the inhabitants of Rapa Nui (Easter Island), a remote island in the southeast Pacific Ocean, have been debated for generations. Archaeological evidence substantiates the widely accepted view that the island was first settled by people of Polynesian origin, as late as 1200 CE [1-4]. What remains controversial, however, is the nature of events in the island's population history prior to the first historic contact with Europeans in 1722 CE. Purported contact between Rapa Nui and South America is particularly contentious, and recent studies have reported genetic evidence for Native American admixture in present-day indigenous inhabitants of Rapa Nui [5-8]. Statistical modeling has suggested that this genetic contribution might have occurred prior to European contact [6]. Here we directly test the hypothesis that the Native American admixture of the current Rapa Nui population predates the arrival of Europeans with a paleogenomic analysis of five individual samples excavated from Ahu Nau Nau, Anakena, dating to pre- and post-European contact, respectively. Complete mitochondrial genomes and low-coverage autosomal genomes show that the analyzed individuals fall within the genetic diversity of present-day and ancient Polynesians, and we can reject the hypothesis that any of these individuals had substantial Native American ancestry. Our data thus suggest that the Native American ancestry in contemporary Easter Islanders was not present on the island prior to European contact and may thus be due to events in more recent history.

Mitogenome Diversity in Sardinians: A Genetic Window onto an Island's Past

Sardinians are "outliers" in the European genetic landscape and, according to paleogenomic nuclear data, the closest to early European Neolithic farmers. To learn more about their genetic ancestry, we analyzed 3,491 modern and 21 ancient mitogenomes from Sardinia. We observed that 78.4% of modern mitogenomes cluster into 89 haplogroups that most likely arose in situ. For each Sardinian-specific haplogroup (SSH), we also identified the upstream node in the phylogeny, from which non-Sardinian mitogenomes radiate. This provided minimum and maximum time estimates for the presence of each SSH on the island. In agreement with demographic evidence, almost all SSHs coalesce in the post-Nuragic, Nuragic and Neolithic-Copper Age periods. For some rare SSHs, however, we could not dismiss the possibility that they might have been on the island prior to the Neolithic, a scenario that would be in agreement with archeological evidence of a Mesolithic occupation of Sardinia.

Sources of Materials for Paleomicrobiology

The Paleomicrobiology establishes the diagnosis of ancient infectious diseases by studying ancient pathogens. This recent science also analyzes the evolution of these pathogens, virulence, and their adaptation to their habitat and their vectors. The DNA persists a long time after the death of an organism despite the chemical and enzymatic degradation. The possibility of sequencing bacterial, viral, parasitic and archaeal DNA molecules persists over time.Various sources are used for these studies: frozen tissue and particularly human tissue are a exceptional source for the analysis because at very low temperatures, all biological activity is suspended. The coprolites are a source of choice for studying the human microbiome. Other sources, the ancient bones are the most abundant, however, they may contain only small amounts of DNA due to natural leaching. When the use of the tooth is possible, is a particularly interesting source because of its highly mineralized structure, which gives greater persistence than bone. The calcified tartar deposited on teeth is a source of interest for the study of oral microbiome.All these sources are subject to precautions (gloves and masks hat) at the time of sampling to avoid cross contamination and also be listed in the most precise way because they are precious and rare.

Paleogenomic Evidence for Multi-generational Mixing between Neolithic Farmers and Mesolithic Hunter-Gatherers in the Lower Danube Basin

The transition from hunting and gathering to farming involved profound cultural and technological changes. In Western and Central Europe, these changes occurred rapidly and synchronously after the arrival of early farmers of Anatolian origin [1-3], who largely replaced the local Mesolithic hunter-gatherers [1, 4-6]. Further east, in the Baltic region, the transition was gradual, with little or no genetic input from incoming farmers [7]. Here we use ancient DNA to investigate the relationship between hunter-gatherers and farmers in the Lower Danube basin, a geographically intermediate area that is characterized by a rapid Neolithic transition but also by the presence of archaeological evidence that points to cultural exchange, and thus possible admixture, between hunter-gatherers and farmers. We recovered four human paleogenomes (1.1× to 4.1× coverage) from Romania spanning a time transect between 8.8 thousand years ago (kya) and 5.4 kya and supplemented them with two Mesolithic genomes (1.7× and 5.3×) from Spain to provide further context on the genetic background of Mesolithic Europe. Our results show major Western hunter-gatherer (WHG) ancestry in a Romanian Eneolithic sample with a minor, but sizeable, contribution from Anatolian farmers, suggesting multiple admixture events between hunter-gatherers and farmers. Dietary stable-isotope analysis of this sample suggests a mixed terrestrial/aquatic diet. Our results provide support for complex interactions among hunter-gatherers and farmers in the Danube basin, demonstrating that in some regions, demic and cultural diffusion were not mutually exclusive, but merely the ends of a continuum for the process of Neolithization.

The study of human Y chromosome variation through ancient DNA

High throughput sequencing methods have completely transformed the study of human Y chromosome variation by offering a genome-scale view on genetic variation retrieved from ancient human remains in context of a growing number of high coverage whole Y chromosome sequence data from living populations from across the world. The ancient Y chromosome sequences are providing us the first exciting glimpses into the past variation of male-specific compartment of the genome and the opportunity to evaluate models based on previously made inferences from patterns of genetic variation in living populations. Analyses of the ancient Y chromosome sequences are challenging not only because of issues generally related to ancient DNA work, such as DNA damage-induced mutations and low content of endogenous DNA in most human remains, but also because of specific properties of the Y chromosome, such as its highly repetitive nature and high homology with the X chromosome. Shotgun sequencing of uniquely mapping regions of the Y chromosomes to sufficiently high coverage is still challenging and costly in poorly preserved samples. To increase the coverage of specific target SNPs capture-based methods have been developed and used in recent years to generate Y chromosome sequence data from hundreds of prehistoric skeletal remains. Besides the prospects of testing directly as how much genetic change in a given time period has accompanied changes in material culture the sequencing of ancient Y chromosomes allows us also to better understand the rate at which mutations accumulate and get fixed over time. This review considers genome-scale evidence on ancient Y chromosome diversity that has recently started to accumulate in geographic areas favourable to DNA preservation. More specifically the review focuses on examples of regional continuity and change of the Y chromosome haplogroups in North Eurasia and in the New World.

Origin and spread of human mitochondrial DNA haplogroup U7

Human mitochondrial DNA haplogroup U is among the initial maternal founders in Southwest Asia and Europe and one that best indicates matrilineal genetic continuity between late Pleistocene hunter-gatherer groups and present-day populations of Europe. While most haplogroup U subclades are older than 30 thousand years, the comparatively recent coalescence time of the extant variation of haplogroup U7 (~16–19 thousand years ago) suggests that its current distribution is the consequence of more recent dispersal events, despite its wide geographical range across Europe, the Near East and South Asia. Here we report 267 new U7 mitogenomes that – analysed alongside 100 published ones – enable us to discern at least two distinct temporal phases of dispersal, both of which most likely emanated from the Near East. The earlier one began prior to the Holocene (~11.5 thousand years ago) towards South Asia, while the later dispersal took place more recently towards Mediterranean Europe during the Neolithic (~8 thousand years ago). These findings imply that the carriers of haplogroup U7 spread to South Asia and Europe before the suggested Bronze Age expansion of Indo-European languages from the Pontic-Caspian Steppe region.

Ancient individuals from the North American Northwest Coast reveal 10,000 years of regional genetic continuity

Recent genomic studies of both ancient and modern indigenous people of the Americas have shed light on the demographic processes involved during the first peopling. The Pacific Northwest Coast proves an intriguing focus for these studies because of its association with coastal migration models and genetic ancestral patterns that are difficult to reconcile with modern DNA alone. Here, we report the low-coverage genome sequence of an ancient individual known as "Shuká Káa" ("Man Ahead of Us") recovered from the On Your Knees Cave (OYKC) in southeastern Alaska (archaeological site 49-PET-408). The human remains date to ∼10,300 calendar (cal) y B.P. We also analyze low-coverage genomes of three more recent individuals from the nearby coast of British Columbia dating from ∼6,075 to 1,750 cal y B.P. From the resulting time series of genetic data, we show that the Pacific Northwest Coast exhibits genetic continuity for at least the past 10,300 cal y B.P. We also infer that population structure existed in the late Pleistocene of North America with Shuká Káa on a different ancestral line compared with other North American individuals from the late Pleistocene or early Holocene (i.e., Anzick-1 and Kennewick Man). Despite regional shifts in mtDNA haplogroups, we conclude from individuals sampled through time that people of the northern Northwest Coast belong to an early genetic lineage that may stem from a late Pleistocene coastal migration into the Americas.

Complete mitochondrial sequences from Mesolithic Sardinia

Little is known about the genetic prehistory of Sardinia because of the scarcity of pre-Neolithic human remains. From a genetic perspective, modern Sardinians are known as genetic outliers in Europe, showing unusually high levels of internal diversity and a close relationship to early European Neolithic farmers. However, how far this peculiar genetic structure extends and how it originated was to date impossible to test. Here we present the first and oldest complete mitochondrial sequences from Sardinia, dated back to 10,000 yBP. These two individuals, while confirming a Mesolithic occupation of the island, belong to rare mtDNA lineages, which have never been found before in Mesolithic samples and that are currently present at low frequencies not only in Sardinia, but in the whole Europe. Preliminary Approximate Bayesian Computations, restricted by biased reference samples for Mesolithic Sardinia (the two typed samples) and Neolithic Europe (limited to central and north European sequences), suggest that the first inhabitants of the island have had a small or negligible contribution to the present-day Sardinian population, which mainly derives its genetic diversity from continental migration into the island by Neolithic times.

Genome-wide data from two early Neolithic East Asian individuals dating to 7700 years ago

Ancient genomes have revolutionized our understanding of Holocene prehistory and, particularly, the Neolithic transition in western Eurasia. In contrast, East Asia has so far received little attention, despite representing a core region at which the Neolithic transition took place independently ~3 millennia after its onset in the Near East. We report genome-wide data from two hunter-gatherers from Devil's Gate, an early Neolithic cave site (dated to ~7.7 thousand years ago) located in East Asia, on the border between Russia and Korea. Both of these individuals are genetically most similar to geographically close modern populations from the Amur Basin, all speaking Tungusic languages, and, in particular, to the Ulchi. The similarity to nearby modern populations and the low levels of additional genetic material in the Ulchi imply a high level of genetic continuity in this region during the Holocene, a pattern that markedly contrasts with that reported for Europe.

Archaic Hominin Admixture Facilitated Adaptation to Out-of-Africa Environments

As modern humans dispersed from Africa throughout the world, they encountered and interbred with archaic hominins, including Neanderthals and Denisovans [1, 2]. Although genome-scale maps of introgressed sequences have been constructed [3-6], considerable gaps in knowledge remain about the functional, phenotypic, and evolutionary significance of archaic hominin DNA that persists in present-day individuals. Here, we describe a comprehensive set of analyses that identified 126 high-frequency archaic haplotypes as putative targets of adaptive introgression in geographically diverse populations. These loci are enriched for immune-related genes (such as OAS1/2/3, TLR1/6/10, and TNFAIP3) and also encompass genes (including OCA2 and BNC2) that influence skin pigmentation phenotypes. Furthermore, we leveraged existing and novel large-scale gene expression datasets to show many positively selected archaic haplotypes act as expression quantitative trait loci (eQTLs), suggesting that modulation of transcript abundance was a common mechanism facilitating adaptive introgression. Our results demonstrate that hybridization between modern and archaic hominins provided an important reservoir of advantageous alleles that enabled adaptation to out-of-Africa environments.

The Demographic Development of the First Farmers in Anatolia

The archaeological documentation of the development of sedentary farming societies in Anatolia is not yet mirrored by a genetic understanding of the human populations involved, in contrast to the spread of farming in Europe [1-3]. Sedentary farming communities emerged in parts of the Fertile Crescent during the tenth millennium and early ninth millennium calibrated (cal) BC and had appeared in central Anatolia by 8300 cal BC [4]. Farming spread into west Anatolia by the early seventh millennium cal BC and quasi-synchronously into Europe, although the timing and process of this movement remain unclear. Using genome sequence data that we generated from nine central Anatolian Neolithic individuals, we studied the transition period from early Aceramic (Pre-Pottery) to the later Pottery Neolithic, when farming expanded west of the Fertile Crescent. We find that genetic diversity in the earliest farmers was conspicuously low, on a par with European foraging groups. With the advent of the Pottery Neolithic, genetic variation within societies reached levels later found in early European farmers. Our results confirm that the earliest Neolithic central Anatolians belonged to the same gene pool as the first Neolithic migrants spreading into Europe. Further, genetic affinities between later Anatolian farmers and fourth to third millennium BC Chalcolithic south Europeans suggest an additional wave of Anatolian migrants, after the initial Neolithic spread but before the Yamnaya-related migrations. We propose that the earliest farming societies demographically resembled foragers and that only after regional gene flow and rising heterogeneity did the farming population expansions into Europe occur.

Fine-Scale Human Population Structure in Southern Africa Reflects Ecogeographic Boundaries

Recent genetic studies have established that the KhoeSan populations of southern Africa are distinct from all other African populations and have remained largely isolated during human prehistory until ∼2000 years ago. Dozens of different KhoeSan groups exist, belonging to three different language families, but very little is known about their population history. We examine new genome-wide polymorphism data and whole mitochondrial genomes for >100 South Africans from the ≠Khomani San and Nama populations of the Northern Cape, analyzed in conjunction with 19 additional southern African populations. Our analyses reveal fine-scale population structure in and around the Kalahari Desert. Surprisingly, this structure does not always correspond to linguistic or subsistence categories as previously suggested, but rather reflects the role of geographic barriers and the ecology of the greater Kalahari Basin. Regardless of subsistence strategy, the indigenous Khoe-speaking Nama pastoralists and the N|u-speaking ≠Khomani (formerly hunter-gatherers) share ancestry with other Khoe-speaking forager populations that form a rim around the Kalahari Desert. We reconstruct earlier migration patterns and estimate that the southern Kalahari populations were among the last to experience gene flow from Bantu speakers, ∼14 generations ago. We conclude that local adoption of pastoralism, at least by the Nama, appears to have been primarily a cultural process with limited genetic impact from eastern Africa.

Early Neolithic genomes from the eastern Fertile Crescent

We sequenced Early Neolithic genomes from the Zagros region of Iran (eastern Fertile Crescent), where some of the earliest evidence for farming is found, and identify a previously uncharacterized population that is neither ancestral to the first European farmers nor has contributed substantially to the ancestry of modern Europeans. These people are estimated to have separated from Early Neolithic farmers in Anatolia some 46,000 to 77,000 years ago and show affinities to modern-day Pakistani and Afghan populations, but particularly to Iranian Zoroastrians. We conclude that multiple, genetically differentiated hunter-gatherer populations adopted farming in southwestern Asia, that components of pre-Neolithic population structure were preserved as farming spread into neighboring regions, and that the Zagros region was the cradle of eastward expansion.

CT Scan of Thirteen Natural Mummies Dating Back to the XVI-XVIII Centuries: An Emerging Tool to Investigate Living Conditions and Diseases in History

Objectives

To correlate the radiologic findings detected with computed tomography scan with anthropological data in 13 naturally mummified bodies discovered during works of recovery of an ancient church in a crypt in Roccapelago, in the Italian Apennines.

Methods

From a group of about sixty not-intentionally mummified bodies, thirteen were selected to be investigated with volumetric computed tomography (CT). Once CT scan was performed, axial images were processed to gather MPR and Volume Rendering reconstructions. Elaborations of these images provided anthropometric measurements and a non-invasive analysis of the residual anatomical structures. For each body the grade of preservation and the eventual pathological changes were recorded. Furthermore, in order to identify nutritional and occupational markers, radiologic signs of bone tropism and degenerative changes were analysed and graded.

Results

Mummies included seven females and six males, with an estimated age ranging from 20 to 60 years. The first relevant finding identified was a general low grade of preservation, due to the lack of anatomic tissues different from bones, tendons and dehydrated skin. The low grade of preservation was related to the natural process of mummification. Analysing bone degenerative changes on CT scan, the majority of the bodies had significant occupational markers consisting of arthritis in the spine, lower limbs and shoulders even in young age. Few were the pathological findings identified. Among these, the most relevant included a severe bilateral congenital hip dysplasia and a wide osteolytic lesion involving left orbit and petrous bone that was likely the cause of death.

Conclusions

Although the low grade of preservation of these mummies, the multidisciplinary approach of anthropologists and radiologists allowed several important advances in knowledge for the epidemiology of Roccapelago. First of all, a profile of living conditions was delineated. It included occupational and nutritional conditions. Moreover, identification of some causes of death and, most importantly the definition of general living conditions.

Ancient DNA and human history

We review studies of genomic data obtained by sequencing hominin fossils with particular emphasis on the unique information that ancient DNA (aDNA) can provide about the demographic history of humans and our closest relatives. We concentrate on nuclear genomic sequences that have been published in the past few years. In many cases, particularly in the Arctic, the Americas, and Europe, aDNA has revealed historical demographic patterns in a way that could not be resolved by analyzing present-day genomes alone. Ancient DNA from archaic hominins has revealed a rich history of admixture between early modern humans, Neanderthals, and Denisovans, and has allowed us to disentangle complex selective processes. Information from aDNA studies is nowhere near saturation, and we believe that future aDNA sequences will continue to change our understanding of hominin history.

Efficient analysis of large datasets and sex bias with ADMIXTURE

BACKGROUND

A number of large genomic datasets are being generated for studies of human ancestry and diseases. The ADMIXTURE program is commonly used to infer individual ancestry from genomic data.

RESULTS

We describe two improvements to the ADMIXTURE software. The first enables ADMIXTURE to infer ancestry for a new set of individuals using cluster allele frequencies from a reference set of individuals. Using data from the 1000 Genomes Project, we show that this allows ADMIXTURE to infer ancestry for 10,920 individuals in a few hours (a 5 × speedup). This mode also allows ADMIXTURE to correctly estimate individual ancestry and allele frequencies from a set of related individuals. The second modification allows ADMIXTURE to correctly handle X-chromosome (and other haploid) data from both males and females. We demonstrate increased power to detect sex-biased admixture in African-American individuals from the 1000 Genomes project using this extension.

CONCLUSIONS

These modifications make ADMIXTURE more efficient and versatile, allowing users to extract more information from large genomic datasets.