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Post by Admin on Feb 6, 2022 0:33:21 GMT
392 Late Neolithic to Bronze Age: The beginning of the Bronze Age was a period of major cultural
393 and demographic change in Eurasia, accompanied by the spread of Yamnaya Steppe Pastoralist
394 related ancestry from Pontic-Caspian steppes into Europe and South Asia (16). The archaeological
395 record documents that the early Steppe pastoralists cultures of Yamnaya and Afanasievo, with
396 characteristic burial styles and pottery, appeared around ~3,300 to 2,600 BCE (35). These groups
397 were likely the result of a genetic admixture between the descendants of EHG-related groups and
398 CHG-related groups associated with the first farmers from Iran (8, 22, 36). Using qpAdm, we first
399 tested how well this model fits the data from 8 early Steppe pastoralist groups, including seven
400 groups associated with Yamnaya culture and one group related to the Afanasievo culture
401 (Methods). For all but two Yamnaya groups (from Hungary Baden and Russia Kalmykia), we
402 found this model provides a good fit to the data (Table S5.4). We note that the samples from
403 Kalmykia in our dataset were shotgun sequenced, and in the qpAdm analysis, we are mixing
404 shotgun and capture data that could potentially lead to technical issues. To understand the timing
405 of the formation of the early Steppe pastoralist-related groups, we applied DATES using pooled
406 EHG and pooled Iranian Neolithic farmers. Focusing on the groups with the largest sample sizes,
407 Yamnaya Samara (n=10) and Afanasievo (n=19), we inferred the admixture occurred between 40–
408 45 generations before the individuals lived, translating to an admixture timing of ~4,100 BCE
409 (Table S6.1). We obtained qualitatively similar dates across four Yamnaya and one Afanasievo
410 groups, consistent with the findings that these groups descend from a recent common ancestor (for
411 Ozera samples from Ukraine, the dates were not significant). This is also further supported by the
412 insight that the genetic differentiation across early Steppe pastoralist groups is very low (FST ~
413 0.000-0.006) (Table S6.2). Thus, we combined all early Steppe pastoralist individuals in one group
414 to obtain a more precise estimate for the genetic formation of proto-Yamnaya of ~4,400 to 4,000
415 BCE (Figure 2). These dates are noteworthy as they pre-date the archaeological evidence by more
416 than a millennium (37) and have important implications for understanding the origin of proto
417 Pontic Caspian cultures and their spread to Europe and South Asia.
418 Over the following millennium, the Yamnaya-derived groups of the Corded Ware Complex
419 (CWC) and Bell Beaker complex (BBC) cultures brought Steppe pastoralist-related ancestry to
420 Europe. Present-day Europeans derive between ~10-60% Steppe pastoralist-related ancestry,
421 which was not seen in Neolithic samples. To obtain a precise chronology of the spread of Steppe
422 pastoralist-related ancestry across Europe, we analyzed 109 late Neolithic, Chalcolithic, and BA
423 samples dated between 3,000-750 CE from 18 regions, including samples associated with the
424 CWC and BBC cultures. We first confirmed that most target samples had Steppe pastoralist-related
425 ancestry, in addition to European HG-related and Anatolian farmer-related ancestry using qpAdm.
426 We excluded 20 groups that could not be parsimoniously modeled as a three-way mixture even
427 after removing individual outliers. After filtering, we retained 79 groups for dating Steppe
428 pastoralist-related gene flow across Europe (Note S5, Table SH). As Bronze Age Europeans have
429 ancestry from three distinct groups, we applied DATES using the following two reference
430 populations, one group including early Steppe pastoralists (Yamnaya and Afanasievo) and the
431 other group with pooled samples of WHG-related and Anatolian farmer-related individuals, which
432 is the proxy for the ancestral Neolithic Europe population.
433 To learn about the spread of CWC culture across Europe, we used seven late Neolithic and
434 Bronze age groups, including five associated with CWC artifacts. Using DATES, we inferred that
435 the oldest date of Steppe pastoralists gene flow in Europe was ~3,200 BCE in Scandinavia in
436 samples associated with Battle Axe Culture in Sweden and Single Grave Culture in Denmark that
437 were both contemporary to CWC. The samples from Scandinavia showed large heterogeneity in
438 ancestry, including some individuals with majority Steppe pastoralist-related ancestry (and
439 negligible amounts of Anatolian farmer-related ancestry), consistent with patterns expected from
440 recent gene flow (38). Strikingly, we inferred the timing of admixture in central Europe (Germany
441 and the Czech Republic) and eastern Europe (Estonia and Poland) to be remarkably similar. These
442 dates fall within a narrow range of ~3,000–2,900 BCE across diverse regions, suggesting that the
443 mixed population associated with the Corded Ware culture formed over a short time and spread
444 across Europe rapidly with very little further mixture (Table SC).
445 Following the Corded Ware culture, from around 2,800 to 2,300 BCE, Bell Beaker pottery
446 became widespread across Europe (39). Using 19 Chalcolithic and Bronze Age samples, including
447 ten associated with Beaker-complex artifacts, we inferred the dynamics of the spread of the Beaker
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Post by Admin on Feb 6, 2022 21:29:03 GMT
 Figure 3: Timeline of admixture events in ancient Europe.
448 complex across Europe. We inferred the oldest date of Steppe pastoralist-related admixture was
449 ~3,200 BCE (3600–2800 BCE) in EBA Mallorca samples from Iberia. We note the EBA Mallorca
450 sample is not directly associated with Beaker culture, but qpAdm modeling suggests that this
451 individual is clade with the small subset of Iberian Beaker-complex-associated individuals who
452 carried Steppe pastoralist-related (40). Most individuals from Iberia, however, had negligible
453 Steppe pastoralist-related ancestry suggesting the Beaker culture was not accompanied by major
454 gene flow in Iberia despite the earliest dates (Table SH). In central and western Europe, where
455 steppe gene flow was more pervasive, we inferred the median date of the mixture was ~2,700 BCE
456 with the oldest dates in the Netherlands, followed by Germany and France (Figure 3). There was,
457 however, large heterogeneity in the dates across Europe and even within the same region. For
458 example, comparing two BA groups from the Netherlands suggests a wide range of dates ~3,000
459 BCE and 2,500 BCE, and four groups from Germany indicate a range of ~2,900–2,700 BCE. From
460 central Europe, the Steppe pastoralist-related ancestry spread quickly to the British Isles, where
461 people with steppe ancestry replaced 90% of the genetic ancestry of individuals from Britain. Our
462 estimates for the time of gene flow in Bell Beakers samples from England suggest that the gene
463 flow occurred ~2,700 BCE (2770-2550 BCE). Our estimated dates of admixture are older than the
464 dates of arrival of this ancestry in Britain (41) and, interestingly, overlap the dates in central
465 Europe. Given that a significant fraction of the Beaker individuals were recent migrants from
466 central Europe, we interpret our dates reflect the admixture into ancestors of the British Beaker
467 people, occurring in mainland Europe (41).
468 The middle to late Bronze age led to the final integration of Steppe pastoralist-related
469 ancestry in Europe. In southern Europe, early BA samples had limited Steppe pastoralist-related
470 ancestry, though present-day individuals have between ~5–30% steppe ancestry (16). Using
471 pooled samples of middle to late BA from Spain, we inferred major mixture occurred ~2,500 BCE
472 in Iberia. We inferred a similar timing in Italy using individuals associated with the Bell Beaker
473 culture and early BA samples from Sicily (Table SC). In Sardinia, a majority of the BA samples
474 do not have Steppe pastoralist-related ancestry. In a few individuals, we found evidence for steppe
475 ancestry, though in most cases, the Steppe pastoralist-related ancestry proportion overlapped 0,
476 and the dates were very noisy (Table SH). Using Iron Age samples from Sardinia, we inferred the
477 gene flow occurred ~2,600 BCE, though there is large uncertainty associated with this estimate
478 (2,614 +/- 560 BCE). In other parts of continental Europe and the British Isles, the Steppe
479 pastoralist-related gene flow got diluted over time, as evidenced by more recent dates in LBA than
480 EBA or MBA samples in Germany, England, and Scotland, and increase in Neolithic farmer
481 ancestry during this period (42) (Table SC).
482 Finally, the Corded Ware Complex expanded to the east to form the archaeological
483 complexes of Sintashta, Srubnaya, Andronovo, and the Bronze Age cultures of Kazakhstan.
484 Samples associated with these cultures harbor mixed ancestry from the Yamnaya Steppe
485 pastoralist-related groups (CWC, in some cases) and Neolithic individuals from central Europe
486 (Table S5.5) (8). Applying DATES to 8 Middle to late Bronze Age (MLBA) Steppe pastoralist
487 groups, we inferred the precise timing for the formation of these groups beginning in the third
488 millennium BCE. These groups were formed chronologically, with the date of genetic formation
489 of ~3,200 BCE for Sintashta culture, followed by ~2,900 BCE for Srubnaya and Andronovo
490 cultures. In the central Steppe region (present-day Kazakhstan), we obtained median dates of
491 ~2,800 BCE for the expansion of Steppe pastoralist-related ancestry in four Kazakh cultures of
492 Maitan Alakul, Aktogai, and Kairan. By ~2,700 BCE, most of these cultures had almost 60-70%
493 Yamnaya Steppe pastoralist-related ancestry (Table SC). These groups, in turn, expanded
494 eastwards, transforming the genetic composition of populations in South Asia.
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Post by Admin on Feb 6, 2022 23:48:44 GMT
495 Discussion
496
497 We developed DATES, a novel method to measure ancestry covariance in a single diploid
498 individual genome to estimate the time of admixture. Using extensive simulations, we show that
499 DATES provides accurate estimates of the timing of admixture for a range of demographic
500 scenarios. Application of DATES to present-day samples shows that the results are concordant with
501 published methods––Rolloff, ALDER, and Globetrotter. For sparse datasets, DATES outperforms
502 published methods as it does not require phased data and works reliably with limited samples,
503 large proportions of missing variants as well as pseudodiploid genotypes. This makes DATES
504 ideally suited for the analysis of ancient DNA samples.
505 We illustrate the application of DATES by reconstructing population movements and
506 admixtures during the European Holocene. The European continent was subject to two major
507 migrations during the Holocene: the movement of Anatolian farmers during the Neolithic and the
508 migration of Yamnaya Steppe pastoralists during the Bronze Age. First, we document that the
509 Mesolithic hunter-gatherers formed as a mixture of WHG and EHG ancestry ~10,200 to 7400
510 BCE. These dates are consistent with the archeological evidence for the appearance of lithic
511 technology associated with eastern HGs in Scandinavia and the Baltic regions and the spread of
512 WHG ancestry to east (17, 43, 44). Next, we studied the timing of the genetic formation of
513 Anatolian farmers. The earliest evidence of agriculture comes from the Fertile Crescent, the
514 southern Levant, and the Zagros Mountains of Iran and dates to around 10,000 BCE. In central
515 Anatolia, farming has been documented c. 8,300 BCE (45, 46). It has been long debated if
516 Neolithic farming groups from Iran and the Levant introduced agriculture to Anatolia or hunter517 gatherers in the region locally adopted agricultural practices. The early Anatolian farmers can be
518 modeled as a mixture of local hunter-gatherers people related to Caucasus hunter-gatherers or first
519 farmers from Iran (26). By applying DATES (assuming single instantaneous admixture), we
520 inferred that the Iran Neolithic gene flow occurred around 10,900 BCE (~12,200–9,600 BCE). An
521 alternate possibility is that there was a long period of gradual gene flow between the two groups
522 and our dates reflect intermediate dates between the start and end of the gene flow. An upper bound
523 for such mixture comes from the lack of Iran Neolithic ancestry in Anatolian HGs at 13,000 BCE,
524 and a lower bound comes from the C14 dates of early Anatolian farmers, one of which is directly
525 dated at 8269–8210 BCE (26). In either case (instantaneous admixture or gradual gene flow), the
526 genetic mixture that formed Anatolian farmers predates the advent of agriculture in this region.
527 This supports the model that Anatolian hunter-gatherers locally transitioned to agricultura
528 subsistence, and most probably, there was cultural diffusion from other regions in Near East (Iran
529 and Levant) (26). Future studies with more dense temporal sampling will shed light on the
530 demographic processes that led to the transition from foraging to farming in the Near East, and in
531 turn, elucidate the relative roles of demic and cultural diffusion in the dispersal of technologies
532 like agriculture across populations.
533 Using data from sixteen regions in Europe, we reconstruct a detailed chronology and
534 dynamics of the expansion and admixture of Anatolian farmers during the Neolithic period. We
535 infer that starting in ~6,400 BCE, gene flow from Anatolian farmers became widespread across
536 Europe, and by ~4,300 BCE, it was present in almost all parts of continental Europe and the British
537 Isles. These dates are significantly more recent than the estimates of farming based on
538 archaeological evidence in some parts of Europe, suggesting that the local hunter-gatherers and
539 farmers co-existed for more than a millennium before the mixture occurred (16, 31). In many
540 regions, after the initial mixture, there was a resurgence of HG ancestry, highlighting the
541 complexities of these ancient interactions. We note that our results are consistent with two previous
542 genetic studies, Lipson et al. (2017) and Rivollat et al. (2020), that applied genetic dating methods
543 to a subset of samples we used in our analysis. Lipson et al. (2017) used a modified version of
544 ALDER to infer the timing of admixture in three regions (n=151), and we obtained statistically
545 consistent results for all overlapping samples (within two standard errors). An advantage of our
546 approach over the modified ALDER approach is that we do not rely on helper samples (higher
547 coverage individuals combined with the target group) for dating; unless these have a similar
548 ancestry profile, they could bias the inferred dates. Our results are concordant with Rivollat et al.
549 (2020) that used a previous version of DATES to infer the timing of Neolithic gene flow in 32
550 groups (vs. 86 groups in our study). We find the performance of both versions of DATES is similar,
551 though some implementation details have improved (see Note S3, Table S3.3).
552 The second major migration occurred when populations associated with the Yamnaya
553 culture in the Pontic-Caspian steppe expanded to central and western Europe from far eastern
554 Europe. Our analysis reveals the precise timing of the genetic formation of these early Steppe
555 pastoralists groups–Yamnaya and Afanasievo–occurred ~4,400-4,000 BCE. This estimate
556 predates the archaeological evidence by more than a millennium (37) and suggests the presence of
557 an ancient “ghost” population of proto-Yamnaya around this time. Understanding the source and
558 location of this ghost population will provide deep insights into the history of Pontic-Caspian
559 cultures and the origin of Indo-European languages that have been associated to have spread with
560 Steppe pastoralists ancestry to Europe and South Asia (16, 47). Starting in ~3,200 BCE, the
561 Yamnaya-derived cultures of Corded Ware Complex and Bell Beaker complex spread westwards,
562 bringing steppe ancestry to Europe. Our analysis reveals striking differences in the spread of these
563 three cultures: the Yamnaya were genetically formed a millennium before the evidence for
564 pastoralism, while CWC formation is coincident with the archaeological dates and similar across
565 diverse regions separated by thousands of kilometers, suggesting a rapid spread after the initial
566 formation of this group. In contrast, the formation and expansion of people with Steppe pastoralist
567 related ancestry associated with Bell Beakers cultural artifacts are much more complex and
568 heterogeneous across regions. We find the earliest evidence of Steppe pastoralist-related ancestry
569 in Iberia around 3200 BCE, though this ancestry only becomes widespread after 2,500 BCE. In
570 central Europe, the gene flow occurred simultaneously with archaeological evidence and was
571 coexisting with the Corded Ware complex in some parts (41, 48). Finally, in the British Isles, the
572 Bell Beaker culture spreads rapidly from central Europe and replaces almost 90% of the ancestry
573 of individuals in this region (41).
574 Recent analysis has shown remarkable parallels in the history of Europe and South Asia;
575 with both groups deriving ancestry from local indigenous HGs, Near Eastern farmers, and Steppe
576 pastoralist-related groups (8). Interestingly, however, the timing of the two major migrations
577 events differs across the two subcontinents. Both mixtures occurred in Europe almost a millennium
578 before they occurred in South Asia. In Europe, the Neolithic migrations primarily involved
579 Anatolian farmers, while the source of Neolithic ancestry is closer to Iran Neolithic farmers in
580 South Asia. The Steppe pastoralist-related gene flow occurred in the context of the spread of CWC
581 and BBC cultures in Europe around 3,200-2,500 BCE; in South Asia, this ancestry arrived with
582 Steppe MLBA cultures in 1,800-1,500 BCE (8). The Steppe MLBA groups were genetically
583 formed as an admixture of Steppe pastoralist-derived groups and European Neolithic farmers
584 following the eastward expansion of CWC groups between ~3,200–2,700 BCE. Understanding the
585 origin and migration paths of the ancestral groups thus helps to illuminate the differences in the
586 timeline of the spread of steppe genetics across the two subcontinents of Eurasia.
587 Genomic dating methods like DATES provide an independent and complementary
588 approach for reconstructing population history. By focusing on genetic clocks like recombination
589 rate, we provide an independent estimate of the timing of evolutionary events up to several
590 thousands of years. Our analysis also has advantages over temporal sampling of ancient DNA, in
591 that we can obtain direct estimates of when a population was formed, rather than inferring putative
592 bounds for the timing based on the absence/presence of a particular ancestry signature (which may
593 be sensitive to sampling choice and density). Genetic approaches provide complementary evidence
594 to archaeology and linguistics as they date the time of gene flow and not migration. Both dates are
595 similar in many contemporary populations like African Americans and Latinos, though this may
596 not be generally true (2). This is underscored by our dates for the Neolithic farmer mixture, which
597 post-dates evidence of material culture related to agriculture by almost two millennia in some
598 regions. This suggests that European HGs and farmers resided side by side for several thousand
599 years before gene exchange (49, 50). This highlights how genetic dates can provide
600 complementary evidence to archaeology and help to build a comprehensive picture of population
601 origins and movements.
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Post by Admin on Mar 7, 2022 21:21:21 GMT
Re-examining Late Chalcolithic Cultural Collapse in South-East Europe Harvey Benjamin Smith University of Arkansas, Fayetteville  ABSTRACT Research into the Balkan Chalcolithic often overlooks the dramatic changes in society that occurred beginning in the late Fifth Millennium BCE. Most settlements were abandoned along with changes in mortuary customs, ceramic and decorative traditions, domestic rituals, crafts, housing styles, mining, and metallurgy. These changes happened at a time when these Chalcolithic societies seemed to be at their peak. Theories as to what caused these changes include migrations/invasions, anthropogenic environmental degradation, gradual internal changes through innovation and outside contacts, and climate change. This thesis attempts to synthesize, and critique material relating to this topic, and ultimately provide my own opinions and suggestions for further research.
INTRODUCTION
The Chalcolithic period in Southeast Europe was a remarkable and dynamic time in
prehistory. It was an autonomous cultural-complex that was on the verge of what we would call
civilized life with its achievements in the metallurgical industry, architecture, trade, art, ideology
and the rise of craft productions and divisions of labor. It was among the most sophisticated and
technologically advanced regions in the world. The Copper Age was a crucial period for the
development of both technology and social complexity. There is no evidence of social hierarchy prior to this period. The centuries between 5000 and 3500 B.C. can now be seen as a crucial transition period during which early Europeans began to use metal tools, develop more complex social structures, and established far reaching cultural and trading
networks.
Yet perhaps even more remarkable and deserving of research is how these societies
ended. One of the most dramatic and overlooked changes to occur in the Old World prehistory
was that which took place in the fourth millennium BC in Southeast Europe during what is called
the Chalcolithic-Early Bronze Age transition. It was more than just a change in metallurgical
technology. There is uncontestable evidence of an entire restructuring of
society throughout the whole region. There were ubiquitous transformations in settlement and
land use, technology, material culture, and even perhaps ideology and language. Much like the
Late Bronze Age Collapse that is marked by the collapse of many of the great Bronze Age
civilizations in the Eastern Mediterranean, the Late Chalcolithic collapse in the Balkans remains
mysterious with a number of different hypothetical causes. In this thesis I will
provide a synthesis of some of the major works done on this topic, the different hypothesis and
ideas up to this point. The main focus of this paper will be on the collapse on the Gumelnita
culture, but I will look at other areas as well to look for possible connections.
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Post by Admin on Mar 7, 2022 22:04:03 GMT
First it is necessary to go over the cultural patterns and chronology of the Southeast European
Chalcolithic and what made it unique in order to understand the changes that occurred at the
end of this period. I will also provide a brief background of the history of archaeology in
Southeast Europe in which we stand on now. How did we get to know the Chalcolithic Balkans
as a unique cultural entity?
The Chalcolithic, or Copper Age, is commonly used as a transitional period between the
Neolithic and Bronze Age because it does not fit into the classic three Three-Age System. It is
also commonly referred to as the Eneolithic in Bulgaria. In the Balkans, the Copper Age
deserves its own proper distinction because it lasted for so long there (as long or longer than
the bronze age) and produced such a unique society. Colin Renfrew lent credit to this idea with
his book that he expressively titled The Autonomy of the Southeast European Copper Age
(1969). It was perhaps one of the most densely populated regions on Earth at its climax in the
mid-fifth millennium. It is in Serbia that we actually find evidence of some of the oldest copper
smelting at 7000 years old (Chapman 1981, Bower 2010). If not the oldest,
then certainly independent from Southwest Asian or Caucasian sources at least. We also find the
first gold ornaments and possible evidence of social elites at the necropolis at Varna in the midfifth millennium (Ivanov 1978, Renfrew 1986). But why was there so much settlement abandonment and cultural change on a regional scale in the 4rth millennium in a different trajectory.
As I examine the different literature pertaining to this matter, I will provide some
critiques and provide a summary analysis tying it all together, a history of theory. My goal is to
synthesize and reexamine old ideas. I will reevaluate them as all logical in their own right.
Where are we today as far as understanding this problem and how has it changed? I will give a
brief historiography of the most important developments in our understanding of
the Chalcolithic and then give a lengthier review of the literature pertaining to its collapse. The
choice of those who are to be analyzed will be weighted toward those who have had the most
theoretical stance and influence in academic and professional circles. Whereas local Balkan
countries are taking the initiative to do new fieldwork often in cooperation with the Germans,
new research seems to be lacking from English speaking institutions (Currently the German
Archaeological Institute is conducting fieldwork with the research goals of this essay in mind). I
will also give my suggestions on what is needed to take Balkans Chalcolithic archaeology to the
next level in an area that is perhaps lacking in new data.
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