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Post by Admin on Oct 26, 2021 20:03:21 GMT
Genetics proves it: Indo-European did not come to Europe on horseback 20 October 2021 Horses were first domesticated in South-West Russia, is the conclusion drawn by an international team of researchers writing in the well-respected journal Nature. Their conclusion resolves a longstanding archaeological question. But, surprisingly enough, this domestication did not contribute to the rapid spread of Indo-European languages in Europe, according to a sub-study carried out in Leiden. In the Nature article, the researchers conclude that the first horses were domesticated some five thousand years ago in the region between the Volga and the Don, two rivers in the west of Russia. Based on DNA research on 273 ancient horse skeletons, they have managed to determine the exact location where horses were first domesticated, thus settling a longstanding discussion in archaeology. A sub-study carried out by Leiden linguist Guus Kroonen has, however, shown that the domestication of horses was not the cause of the rapid spread of Indo-European languages in Europe in the same period. This language family was brought to Europe five thousand years ago by Russian immigrants, and became the dominant language here. Indo-European is still the predecessor of almost all European languages, including Dutch. But the recent domestication of horses did not play any meaningful role in this. Hypothesis in part dismissed This finding at least in part dismisses an important archaeological and linguistic hypothesis, Kroonen explains. Linguists have been trying for a long time to work out how the Indo-European language family managed to spread so rapidly and so successfully. Popular theory has it that the domestication of horses may have played a role in this because horses allowed people to travel faster. But this research shows that the theory does not hold for Europe. Kroonen reached this conclusion after he and several other archaeologists had examinations made of the remains of horses from the period when Indo-European was spreading over Europe. The examination showed that none of these European horses were descended from the horses from the Russian steppes, the animals that were the first to be domesticated. The conclusion is thus that the Russian immigrants must have come to Europe on foot, bringing the Indo-European language with them, but leaving the horses behind in Russia.  Guus Kroonen Horses did play a role in India Surprisingly enough, horses do seem to have played a role in the spread of the language family in India, thus from Russia in an easterly direction. Indo-European was introduced there one millennium later, together with combat chariots. 'Maybe it took that thousand years to breed and domesticate horses so that they were able to make such long journeys,' Kroonen hypothesises. 'You can imagine that a half-wild horse is unlikely to carry a rider or draw a chariot. Horses were probably kept in the early period mainly to provide meat and milk.' The research reported on in Nature was carried out by a multidisciplinary team of archaeologists, geneticists and linguists. For his sub-study, Kroonen worked with Leiden archaeologist Quentin Bourgeois, who went with Kroonen in search of ancient remains of horses. 'I think the collaboration among different disciplines is really fantastic,' Kroonen says. 'We are now able to test ages-old questions using evidence from genetics and archaeology. All of a sudden, that brings the answers to major questions within reach.' Looking for other causes Even so, the results of his own research came as a surprise, says Kroonen. 'Secretly, I suspected that the domestication of horses would play some kind of role. When this proved not to be the case, it felt like an anticlimax. But, on the other hand, we can now look further for the real causes. We know for sure that Indo-European appeared very suddenly, but this change was probably not related to a transport revolution, but to changes in lifestyle, such as the advent of pastoralism.' Neolithic population crash in northwest Europe associated with agricultural crisis Abstract The focus of this paper is the Neolithic of northwest Europe, where a rapid growth in population between ∼5950 and ∼ 5550 cal yr BP is followed by a decline that lasted until ∼ 4950 cal yr BP. The timing of the increase in population density correlates with the local appearance of farming and is attributed to the advantageous effects of agriculture. However, the sub-sequent population decline has yet to be satisfactorily explained. One possible explanation is the reduction in yields in Neo-lithic cereal-based agriculture due to worsening climatic conditions. The suggestion of a correlation between Neolithic climate deterioration, agricultural productivity, and a decrease in population requires testing for northwestern Europe. Data for our analyses were collected during the Cultural Evolution of Neolithic Europe project. We assess the correlation between agricultural productivity and population densities in the Neolithic of northwest Europe by examining the changing frequencies of crop and weed taxa before, during and after the population “boom and bust.” We show that the period of pop-ulation decline is coincidental with a decrease in cereal production linked to a shift towards less fertile soils. Keywords: Neolithic Europe; Population change; Farming systems; Agricultural productivity; |
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Post by Admin on Oct 26, 2021 21:15:30 GMT
 More than 5000 years ago, nomads known today as the Yamnaya rumbled out of the grasslands of modern-day Russia and Ukraine in heavy, ox-drawn wagons. Within just a few centuries they had expanded across Eurasia, leaving a genetic signature in populations from Mongolia to Hungary. Now, fossilized plaque from the teeth of more than 50 Bronze Age skeletons suggests an unlikely weapon powered their expansion: milk. “It’s great to see this type of evidence finally there,” says Wolfgang Haak, an archaeogeneticist at the Max Planck Institute for Evolutionary Anthropology who was not involved in the research. “It’s a convincing argument as far as dairy is concerned.” Researchers have long speculated that a combination of wagons, dairying, and horseback riding might have made it possible for the Yamnaya—whom Haak refers to as “eastern cowboys”—to develop a new, more mobile way of life, unleashing their unprecedented expansion. But there was little direct evidence to back that up that idea, aside from a few wagon burials and pottery sherds. To see what might have fueled the Yamnaya’s success, researchers from the United States, Europe, and Russia looked for milk proteins trapped and preserved in the dental calculus, or plaque, of people living on the steppes of modern-day Russia between 4600 and 1700 B.C.E. They examined 56 skeletons from more than two dozen sites north of the Caspian Sea. The team separated the preserved proteins from the mineral matrix of the plaque and then used mass spectrometry to identify individual proteins. Prior to 3300 B.C.E., calculus from the teeth of people living in settlements along the Volga and Don rivers contained virtually no milk proteins. Instead, these pre-Yamnaya groups likely consumed lots of freshwater fish, wild game, and the occasional meal of domesticated cow, sheep, or goat meat, as suggested by previous analysis of isotopes in their skeletons and animal bones at the sites. Then, around 3300 B.C.E., something changed. Samples scraped from the teeth of people living after that date were full of cow, sheep, and goat milk proteins—direct evidence they were eating dairy products. A few even had trace amounts of preserved horse milk. “There’s a cultural switch,” says lead author Shevan Wilkin, a biomolecular archaeologist at the University of Zurich Institute of Evolutionary Medicine. “It’s a huge change of perspective from ‘we eat these animals sometimes’ to ‘we milk them all the time.’” The proteins suggest the adoption of dairying and herding was key to the rapid transformation of hunter-gatherers into nomadic herders—and their expansion across Eurasia in the space of just 300 years, the researchers write today in Nature. “Horses, cattle, sheep, and goats turned grass into food, clothing, and shelter,” says Hartwick College archaeologist and co-author David Anthony. “The Yamnaya invented a new economy.”  But dairy didn’t do it alone: The introduction of wagons around the same time made carrying water and following grazing animals to distant pastures possible. Meanwhile, early domesticated horses might have enabled the newly nomadic Yamnaya to manage bigger herds. Together, the innovations opened up a vast new landscape. “Milk is a contributing factor, but not the only factor,” says University of Helsinki archaeologist Volker Heyd, who was not involved in the research. “It’s a new economy and a new way of life, and the origins are the invention of the wheel, horse riding, and dairying.” One mystery remains. Previous analyses of ancient DNA have shown the Yamnaya lacked the genetic ability to metabolize milk sugars—in other words, they were lactose intolerant. It’s possible, Wilkin says, that—much like modern Mongolians—the Yamnaya consumed fermented dairy products like yogurt or hard cheeses, which contain virtually no lactose. Whatever form of dairy they consumed, she adds, “I don’t know how you would have moved that far that fast [without it].” doi: 10.1126/science.acx9119 |
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Post by Admin on Oct 27, 2021 3:49:16 GMT
Dairying enabled Early Bronze Age Yamnaya steppe expansions
Abstract
During the Early Bronze Age, populations of the western Eurasian steppe expanded across an immense area of northern Eurasia. Combined archaeological and genetic evidence supports widespread Early Bronze Age population movements out of the Pontic–Caspian steppe that resulted in gene flow across vast distances, linking populations of Yamnaya pastoralists in Scandinavia with pastoral populations (known as the Afanasievo) far to the east in the Altai Mountains1,2 and Mongolia3. Although some models hold that this expansion was the outcome of a newly mobile pastoral economy characterized by horse traction, bulk wagon transport4,5,6 and regular dietary dependence on meat and milk5, hard evidence for these economic features has not been found. Here we draw on proteomic analysis of dental calculus from individuals from the western Eurasian steppe to demonstrate a major transition in dairying at the start of the Bronze Age. The rapid onset of ubiquitous dairying at a point in time when steppe populations are known to have begun dispersing offers critical insight into a key catalyst of steppe mobility. The identification of horse milk proteins also indicates horse domestication by the Early Bronze Age, which provides support for its role in steppe dispersals. Our results point to a potential epicentre for horse domestication in the Pontic–Caspian steppe by the third millennium BC, and offer strong support for the notion that the novel exploitation of secondary animal products was a key driver of the expansions of Eurasian steppe pastoralists by the Early Bronze Age.
Main
The pastoralist populations of the Eurasian steppe have long been a source of archaeological and historical fascination. Although the later history of steppe pastoralists—including the rise of the Xiongnu and Mongol empires in the east—is reasonably well-established, the early emergence and expansion of pastoralist groups in the steppe occurred before the historical era and has largely been reconstructed on the basis of archaeological and linguistic data1,6,7. More recently, ancient DNA evidence has provided insights into early steppe populations, revealing evidence for a major influx of steppe ancestry into Europe in the Late Neolithic that effectively transformed the European genetic landscape1,2,8. Archaeogenetic data also link these same populations (referred to as Yamnaya) with pastoral Afanasievo populations far to the east in the Altai Mountains1,2 and Mongolia3. Combined archaeological and genetic evidence supports widespread population movements in the Early Bronze Age (about 3300 to 2500 BC) from the Pontic–Caspian steppe that resulted in gene flow across vast distances, linking Yamnaya pastoralist populations in Scandinavia with groups that expanded into Siberia9.
Although the Yamnaya expansions are well-established, the driving forces behind them remain unclear. A widely cited theory holds that the early spread of herders across Eurasia was facilitated by a newly mobile pastoral economy that was made possible by a combination of horse traction and bulk wagon transport4,5,6. Together with regular dietary dependence on meat and milk5, this opened up the steppe to exploitation and occupation by pastoralist communities. Yet for all its persuasiveness, the model remains inadequately supported by direct archaeological or biomolecular data. Archaeological evidence for the use of bulk wagon transport by the Eneolithic Maikop and Early Bronze Age Yamnaya groups exists in the form of carts and bridling materials10, but two other critical components of the model—a reliance on domesticated horses and ruminant dairying—remain archaeologically unproven.
The domestication status of Eurasian horses has long been debated5,6,11,12,13,14, and recent archaeogenetic findings15 have shifted our understanding of early horses at the Eneolithic site of Botai in northern Kazakhstan by identifying them as Equus przewalskii rather than the modern-day domestic horse (Equus caballus)5,6. Although horses do appear in Early Bronze Age assemblages on the steppe, it remains unclear whether they were being ridden7,11,16,17, or indeed whether they were part of pastoral herds or simply hunted. On the eastern Eurasian steppe, growing evidence suggests that horses were not ridden11,12,18 or milked19 before about 1200 BC, and horses may have been uncommon in early pastoralist assemblages20. Early ruminant dairying on the western steppe has also been inadequately demonstrated, as human stable isotope data from the region suggests—but cannot confirm—dairy consumption21,22. Palaeoproteomics, which is the only method that is able to evince individual dairy consumption (rather than milk production) and provide taxonomic resolution, has so far been minimally applied to steppe populations. Across Yamnaya and Afanasievo populations, dairying evidence is available only for a few individuals from the eastern steppe who have ancestry from western steppe groups; the earliest individual provides only a taxonomically ambiguous ruminant (Ovis/Bos) peptide result19.
To address the heavily debated question of what drove Yamnaya expansions across the steppe6,23,24,25, we conducted proteomic analysis of dental calculus sampled from 56 steppe individuals who span the Eneolithic to Late Bronze Age, and who date from between 4600 and 1700 BC. Our samples from the Eneolithic (about 4600 to 3300 BC) are from 19 individuals from 5 sites: Murzikha 2 (6 individuals), Khvalynsk 1 and Khvalynsk 2 (9 individuals), Ekaterinovka Mys (1 individual), Lebyazhinka 5 (1 individual) and Khlopkov Bugor (2 individuals) (Fig. 1, Supplementary Fig. 1a). Ancient DNA results from Khvalynsk and other Eneolithic sites in the Volga and northern Caucasus2,7,26 support the existence of an Eneolithic population across this region that was genetically similar to the Yamnaya population, but who lacked the additional farmer (Anatolian) ancestry that would arrive later on the steppe7. Published stable isotope and archaeological studies applied to Eneolithic populations from the Pontic region point to an economy based on fishing, the gathering of local plants and the keeping of domesticated animals6,21,27,28.Given the importance of the horse in reconstructions of early pastoralist expansions, we also examined dental calculus from two individuals from the well-known site of Botai. With faunal assemblages dominated by horse remains11,12,13 and early lipid studies of ceramics indicating horse milking at the site by 3500 BC13, the site is central to discussions of early horse milking and dairying in the Eurasian steppe.
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Post by Admin on Oct 27, 2021 19:56:23 GMT
Fig. 1: Map showing sites that yielded individuals with preserved ancient proteins.  a–c, Eneolithic (a), Early Bronze Age (b) and Middle–Late Bronze Age (c) sites in the Pontic–Caspian region, showing the number of individuals with a positive dairy identification out of the total number of individuals with preserved ancient proteins for each site. Strong evidence of preservation of equine or ruminant milk protein identifiers are depicted with black animal icons; the single individual with equivocally identified casein peptides is shown with a grey icon. For a map of all sites (including those without preserved proteins), see Supplementary Fig. 1. Base maps were created using QGIS 3.12 (https://qgis.org/en/site/), and use Natural Earth vector map data from www.naturalearthdata.com/downloads/. The horse image is reproduced from ref. 33; sheep silhouette, public domain (https://thenounproject.com/icon/12538/). Our Bronze Age samples come from 35 individuals from 20 sites in the Volga–Ural steppes that can be divided into two chronological groups: the Early Bronze Age (about 3300 to 2500 BC) era of Yamnaya-culture mobile pastoralism29,30; and the Middle–Late Bronze Age transition (about 2500–1700 BC), when chariots, fortified settlements and new western-derived influence genetic ancestries appeared with the Sintashta culture31. The cemetery sites and the number of individuals (in parentheses) from the Early Bronze Age are: Krasikovskyi 1 (2) Krasnokholm 3 (1), Krivyanskiy 9 (2), Kutuluk 1 (2), Leshchevskoe 1 (1), Lopatino 1 (1), Mustayevo 5 (2), Nizhnaya Pavlovka (1), Panitskoe (1), Podlesnoe (1), Pyatiletka (1) and Trudovoy (1); and, from the Middle–Late Bronze Age transition, Bolshekaraganskyi (1), Kalinovsky 1 (2), Kamennyi Ambar 5 (3), Krasikovskyi I (1), Krivyanskiy 9 (3), Lopatino 1 and Lopatino 2 (2), Potapovka 1 (1), Shumayevo 2 (1) and Utevka 6 (5) (Supplementary Fig. 1b, c). Archaeological and stable isotope findings6,22 indicate that the diet of Early Bronze Age Yamnaya groups was focused on herd animals, specifically cattle, sheep and goat. Horse remains also appear in quantity on a few steppe archaeological sites, but the status of Early Bronze Age horses—whether domesticated or hunted—has remained unclear32,33. The Middle–Late Bronze Age transition saw a shift to greater horse exploitation and chariot use, within the context of an ongoing dietary focus on domesticated livestock. Of the 56 ancient human dental calculus samples we tested, 55 were successfully extracted and produced identifiable protein data. Of these 55, 48 (87%) were determined to have strong signals for preservation through an assessment of proteins commonly found within the oral cavity; detailed information on this assessment is provided in Methods, Supplementary Table 3. The earliest samples in our study (about 4600 to 4000 BC) are from 5 Eneolithic sites in southwestern Russia located on or close to the Volga River and its tributaries. Of the samples from these 19 individuals, 11 were successfully extracted and well-preserved, and 10 of these did not show any evidence for dairy consumption (Figs. 1a, 2a). The calculus of one individual contained two peptides specific to bovine (Bos, Bubalis and Bison) α-S1-casein, a milk curd protein. However, as the only dietary peptides contained in this sample were specific to casein and evidence for the most commonly recovered dairy protein β-lactoglobulin (BLG) was lacking, dairy consumption in this individual could not be confidently confirmed. In general, casein peptides appear to preserve more poorly than BLG in archaeological calculus, and thus are most often identified together with other dairy protein peptides rather than alone19,34,35,36,37. Additionally, within the two identified casein peptides, there is only one possible amino acid deamidation site, which renders any estimation of the antiquity of these peptides exceedingly challenging. A previously published paper38 demonstrates the extreme variability in deamidation of amino acids in milk proteins, which further limits our ability to confirm the authenticity of this dairy finding. The calculus from the two additional Botai individuals demonstrated adequate preservation, but also lacked evidence for dairy consumption. |
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Post by Admin on Oct 27, 2021 22:54:25 GMT
Fig. 2: Histogram of taxonomic specificity of dairy peptide spectral matches per individual.  a–c, Histograms for individuals with evidence for consumption of dairy, from the Eneolithic (a), Early Bronze Age (b) and Middle and Late Bronze Age (c). PSM, peptide spectral match. For the Early Bronze Age individuals (dating to the onset of the Yamnaya cultural horizon), dairy peptides were recovered from 15 of the 16 individual calculus samples we analysed (Fig. 1b, 2b). All 15 individuals with positive dairy results contained multiple peptide spectral matches to ruminant dairy proteins (including BLG), and some individuals also contained α-S1 casein, α-S2-casein or both. Although many of the milk peptides were only specific to higher taxonomic levels (such as Pecora, an infraorder within Artiodactyla (cow, sheep, goat, buffalo, yak, reindeer, deer and antelope)), others enabled more specific taxonomic classifications, including to family, genus or species. We found Ovis, Capra and Bos attributions, and the calculus of many individuals contained dairy peptides from several species. Notably, we identified Equus milk peptides from the protein BLGI in 2 of 17 Early Bronze Age individuals, both from the southwestern site of Krivyanskiy 9 (3305 to 2633 calibrated years BC (Supplementary Table 5 provides individual accelerator mass spectrometry dating information)). Although the genus Equus includes horse, donkey and kiang, only horse species (E. caballus, E. przewalskii, Equus hemionus and Equus ferus) are archaeologically attested in the steppe in the Early Bronze Age, supporting the Equus identification as horse. For the Middle–Late Bronze Age transition, calculus samples from 15 of 19 individuals were positive for evidence of ruminant milk consumption (Figs. 1c, 2c). Similar to the Early Bronze Age, we identified BLG, α-S1-casein and α-S2-casein, as well as the whey protein α-lactalbumin. Taxonomic identifications again ranged from the Pecora infraorder to genus-level identifications (including Ovis and Bos), but without any specific identifications for Capra or Equus. Supplementary Table 4 provides a full accounting of all identified dairy proteins for each individual. Overall, our results point to a clear and marked shift in milk consumption patterns between the Eneolithic and Early Bronze Age in the Pontic–Caspian Steppe. The majority of Eneolithic individuals (10 out of 11 (92%)) in our assemblage lack any evidence for milk consumption, whereas the overwhelming majority of Early Bronze Age individuals (15 out of 16 (94%)) contain ample proteomic evidence for dairy consumption in their calculus. Although a single individual at Eneolithic Khvalynsk with somewhat equivocal evidence for the consumption of dairy from cattle may indicate small-scale dairy use, the reliability of this single identification is questionable. Our findings suggest that regular dairy consumption in the Pontic–Caspian Steppe began only at the time of the Eneolithic-to-Early Bronze Age transition. Although neighbouring Eneolithic farming populations in Europe appear to have been dairying39, those living across the steppe frontier did not adopt milking practices, which suggests the presence of a cultural frontier. The proteomic data are in broad agreement with findings from lipid analyses in the Ukraine (Supplementary Information section 2, Supplementary Table 2). They also agree with stable isotope analysis of individuals from Eneolithic-to-Bronze-Age Samara showing a corresponding shift from a heavy reliance on fish, deer and other riverine forest (C3) resources to a greater reliance on terrestrial and grassland (C3 and C4) animal products22,40. One important advantage of proteomic data is their ability, in some cases, to provide species-specific protein identifications. Our study offers evidence for the Bronze Age milking of sheep, goat and cattle, which fits with evidence for the herding of these animals. The lush valleys of the Pontic–Caspian Steppe provided ample forage and hydration for mixed herds of arid-adapted sheep and goat, as well as more water-reliant cattle41,42. Although a recent study has shown that lactase persistence—which results from the presence of an allele that enables production of lactase into adulthood—was rare in steppe populations of the Early Bronze Age43, we find that the western steppe community was regularly consuming dairy that could have included fresh milk and/or other processed products with reduced lactose, such as yogurts, cheeses or fermented milk beverages. Our study of dental calculus from the Eneolithic site of Botai to the east, where early horse milking has been suggested by lipid analysis (albeit equivocally44), did not yield milk proteins. Although two samples are insufficient for drawing broad conclusions, this finding does not support widespread milk consumption at the site13,45,46. However, two calculus samples from Early Bronze Age individuals of the Pontic–Caspian region do provide evidence for the consumption of horse milk. Combined with archaeogenetic evidence15 that places the Botai horses on a different evolutionary trajectory than the domesticated DOM2 E. caballus lineage, this finding—if backed up by further sampling and analysis—would seem to firmly shift the focus of sustained early horse domestication on the Eurasian steppe to the Pontic–Caspian region. So far, the oldest horse specimens that carry the DOM2 lineage date to between 2074 to 1625 calibrated years BC, at which time the lineage is archaeologically attested in present-day Russia, Romania and Georgia15. Our identification of—to our knowledge—the earliest horse milk proteins yet identified on the steppe or anywhere else reveals the presence of domestic horses in the western steppe by the Early Bronze Age, which suggests that the region (where the first evidence for horse chariots later emerged at about 2000 BC47) may have been the initial epicentre for domestication of the DOM2 lineage during the late fourth or third millennium BC. Overall, our findings offer strong support to the notion of a secondary products revolution48,49 in the Eurasian steppe by the Early Bronze Age. This change in subsistence economy, indicated by dietary stable isotopes in human bones as well as by proteomics, was accompanied by the widespread abandonment of Eneolithic riverine settlement sites, the appearance of kurgan cemeteries in the previously unexploited arid plateaus between the river valleys, and the inclusion of wheeled vehicles and occasional horse bones in Yamnaya graves. At the same time, the steppe Yamnaya population expanded westward into Europe and eastward to the Altai Mountains (a range of 6,000 km)1,3,50. Although we cannot offer direct insight into the question of horse riding or traction on the basis of our data, evidence for milked horses certainly makes horse domestication more likely, and may indicate that horses had a role in the spread of Yamnaya groups. The triad of animal traction, dairying and horse domestication appears to have had an instrumental role in transforming Pontic–Caspian economies and opening up the broader steppe to human habitation by the Early Bronze Age. If some or even all of these elements were present before the Bronze Age, it is only from this latter period that we witness their intensive and sustained exploitation amongst numerous groups. Although other factors will no doubt also have been important, the emergence of more mobile, pastoralist societies adapted to survival on the cold and arid steppe—where horses may have opened up snow-covered pasturage for other animals18, and milk would have provided a sustained source of protein, nutrients and fluids—was undoubtedly critical to the expansion of Bronze Age pastoralists such the Yamnaya groups. |
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