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Beginning in 1948, the Soviet Union launched a series of wildly ambitious projects to implement Joseph Stalin's vision of a total \"transformation of nature.\" Intended to increase agricultural yields dramatically, this utopian impulse quickly spread to the newly communist states of Eastern Europe, captivating political elites and war-fatigued publics alike. By the time of Stalin's death, however, these attempts at \"transformation\"-which relied upon ideologically corrupted and pseudoscientific theories-had proven a spectacular failure. This richly detailed volume follows the history of such projects in three communist states-Poland, Hungary, and Czechoslovakia-and explores their varied, but largely disastrous, consequences.

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc . The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries. Genome-wide data from 400 individuals indicate that the initial spread of the Beaker archaeological complex between Iberia and central Europe was propelled by cultural diffusion, but that its spread into Britain involved a large-scale migration that permanently replaced about ninety per cent of the ancestry in the previously resident population. Genomic insights into the Beaker culture Bell Beaker refers to a distinctive pottery style found across western and central Europe during the end of the Neolithic. Previous studies have had conflicting results on the origin and mechanisms of spread of the Beaker culture. David Reich and colleagues report genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, from 136 different archaeological sites, and including 226 Beaker-associated individuals. These individuals were highly genetically heterogeneous, which supports a model in which cultural transmission and human migration both had important roles in the spread of the Beaker culture, with the relative balance of these two processes varying by region. Elsewhere in this issue, David Reich and colleagues analyse genome-wide genomic data from 225 individuals who lived in southeastern European and the surrounding regions between 12000 and 500 bc . They analyse these data in combination with previous genomic datasets to update existing models of the early spread of farming into and across Europe.

Hepatitis B virus (HBV) is a major cause of human hepatitis. There is considerable uncertainty about the timescale of its evolution and its association with humans. Here we present 12 full or partial ancient HBV genomes that are between approximately 0.8 and 4.5 thousand years old. The ancient sequences group either within or in a sister relationship with extant human or other ape HBV clades. Generally, the genome properties follow those of modern HBV. The root of the HBV tree is projected to between 8.6 and 20.9 thousand years ago, and we estimate a substitution rate of 8.04 × 10 −6 –1.51 × 10 −5 nucleotide substitutions per site per year. In several cases, the geographical locations of the ancient genotypes do not match present-day distributions. Genotypes that today are typical of Africa and Asia, and a subgenotype from India, are shown to have an early Eurasian presence. The geographical and temporal patterns that we observe in ancient and modern HBV genotypes are compatible with well-documented human migrations during the Bronze and Iron Ages 1 , 2 . We provide evidence for the creation of HBV genotype A via recombination, and for a long-term association of modern HBV genotypes with humans, including the discovery of a human genotype that is now extinct. These data expose a complexity of HBV evolution that is not evident when considering modern sequences alone. Phylogenies reconstructed using 12 hepatitis B virus genomes, which were recovered from ancient human genome data, reveal a complex history of hepatitis B evolution that is not evident when using only modern samples.

Western Eurasia witnessed several large-scale human migrations during the Holocene 1 – 5 . Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp , consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp , resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations. An analysis involving the shotgun sequencing of more than 300 ancient genomes from Eurasia reveals a deep east–west genetic divide from the Black Sea to the Baltic, and provides insight into the distinct effects of the Neolithic transition on either side of this boundary.

A sequencing study comparing ancient and contemporary genomes reveals that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, ancient north Eurasians (related to Upper Palaeolithic Siberians) and early European farmers of mainly Near Eastern origin. The genetics of European prehistory By sequencing and comparing the genomes of nine ancient Europeans that bridge the transition to agriculture in Europe between 8,000 and 7,000 years ago, David Reich and colleagues show that most present-day Europeans derive from at least three highly differentiated populations — west European hunter-gatherers, ancient north Eurasians (related to Upper Palaeolithic Siberians) and early European farmers of mainly Near Eastern origin. They further propose that early European farmers had about 44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages. These results raise interesting new questions, for instance that of where and when the Near Eastern farmers mixed with European hunter-gatherers to produce the early European farmers. We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes 1 , 2 , 3 , 4 with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians 3 , who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations’ deep relationships and show that early European farmers had ∼44% ancestry from a ‘basal Eurasian’ population that split before the diversification of other non-African lineages.

The Bronze Age of Eurasia (around 3000–1000 BC ) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought. An analysis of 101 ancient human genomes from the Bronze Age (3000–1000 bc ) reveals large-scale population migrations in Eurasia consistent with the spread of Indo-European languages; individuals frequently had light skin pigmentation but were not lactose tolerant. Population changes in Bronze Age Eurasia Was the Bronze Age of a period of major cultural changes because of circulation of ideas or because of large-scale migrations? The authors sequence and analyse low-coverage genomes from 101 ancient humans from across Eurasia to reveal large-scale population migrations and replacements during this time. Analyses indicate that light skin pigmentation was already frequent among Europeans in the Bronze Age but not lactose tolerance, indicating a more recent onset of positive selection on the latter trait than previously believed. The reported findings are also consistent with the spread of Indo-European languages during the Early Bronze Age reported on page 207 of this issue.

A genome-wide analysis of 69 ancient Europeans reveals the history of population migrations around the time that Indo-European languages arose in Europe, when there was a large migration into Europe from the Eurasian steppe in the east (providing a genetic ancestry still present in Europeans today); these findings support a ‘steppe origin’ hypothesis for how some Indo-European languages arose. Steppe change for European languages David Reich and colleagues generated genome-wide data from 69 Europeans who lived between 8,000 and 3,000 years ago. Their analyses reveal that closely related groups of early farmers — different from indigenous hunter-gatherers — appeared in Germany, Hungary and Spain at around 8,000 to 7,000 years ago. At the same time Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a 24,000-year-old Siberian. By 6,000 to 5,000 years ago, a resurgence of hunter-gatherer ancestry had occurred throughout much of Europe, apart from in Russia. Western and Eastern Europe came into contact about 4,500 years ago, leaving traces of steppe ancestry in present-day Europeans. In addition to providing new insights into Neolithic population dynamics, these analyses lend support to the theory of a steppe origin of at least some of the Indo-European languages of Europe. The reported findings are also consistent with a study of 101 Bronze Age genomes reported on page 167 of this issue. We generated genome-wide data from 69 Europeans who lived between 8,000–3,000 years ago by enriching ancient DNA libraries for a target set of almost 400,000 polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and to obtain new insights about the past. We show that the populations of Western and Far Eastern Europe followed opposite trajectories between 8,000–5,000 years ago. At the beginning of the Neolithic period in Europe, ∼8,000–7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a ∼24,000-year-old Siberian 6 . By ∼6,000–5,000 years ago, farmers throughout much of Europe had more hunter-gatherer ancestry than their predecessors, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but also from a population of Near Eastern ancestry. Western and Eastern Europe came into contact ∼4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced ∼75% of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least ∼3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for a steppe origin 9 of at least some of the Indo-European languages of Europe.

Modern humans have populated Europe for more than 45,000 years 1,2 . Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period 3 . Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe 4 , but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants.

Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. Here we analyse genome-wide data from 51 Eurasians from ~45,000–7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas there is no evidence of the earliest modern humans in Europe contributing to the genetic composition of present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans. An ~35,000-year-old individual from northwest Europe represents an early branch of this founder population which was then displaced across a broad region, before reappearing in southwest Europe at the height of the last Ice Age ~19,000 years ago. During the major warming period after ~14,000 years ago, a genetic component related to present-day Near Easterners became widespread in Europe. These results document how population turnover and migration have been recurring themes of European prehistory. Analysis of ancient genomic data of 51 humans from Eurasia dating from 45,000 to 7,000 years ago provides insight into the population history of pre-Neolithic Europe and support for recurring migration and population turnover in Europe during this period. Eurasian humans of the Upper Paleolithic David Reich, Svante Pääbo and colleagues analyse ancient genomic data from 51 Eurasian humans who lived between 45,000 and 7,000 years ago. The data provide the most comprehensive view to date of the population history of pre-Neolithic Europe, and provide support for recurring migration and population turnover in European populations during this period. Neanderthal ancestry has reduced during the past 45,000 years from 3–6% to the present day value of around 2%.