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Post by Admin on Jul 28, 2022 5:58:59 GMT
Unearthing The Bronze Age Fortress Left Untouched For Over 3000 Years | Time Team | Odyssey
211,058 views Nov 6, 2021 A previously unexcavated massive Bronze Age promontory fort conceals the remains of a sophisticated society. Tony and the team have just three days to unearth the mysteries of one of the most significant Bronze Age finds in British archaeology...
Odyssey is your journey into the world of Ancient History; from the dawn of Mesopotamia to the fall of Rome. We'll be bringing you only the best documentaries that journey into the mysteries and ruins of worlds long lost.
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Post by Admin on Aug 20, 2023 19:12:30 GMT
Large-Scale Migration into Britain During the Middle to Late Bronze Age Abstract Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000–875 BCE, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across Central and Western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2–6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain’s independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in Central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in Central Europe over this period. Whole genome ancient DNA studies have shown that the first Neolithic farmers of the island of Great Britain (hereafter Britain) who lived 3950–2450 BCE derived roughly 80% of their ancestry from Early European Farmers (EEF) who originated in Anatolia more than two millennia earlier, and 20% from Mesolithic hunter-gatherers (Western European Hunter-Gatherers: WHG) with whom they mixed in continental Europe, indicating that local WHG in Britain contributed negligibly to later populations7–9. This ancestry profile remained stable for about a millennium and a half. From around 2450 BCE, there was another substantial migration (Box 1) into Britain (minimum 90% ancestry from the new migrants) coinciding with the spread of Bell Beaker traditions from continental Europe which brought a third major component: ‘Steppe ancestry’ derived originally from people living on the Pontic-Caspian Steppe ~3000 BCE8. In the original study8 reporting this ancestry shift in Britain, no significant average change in the proportion of EEF ancestry was detected from the Chalcolithic/Early Bronze Age (C/EBA; 2450–1550 BCE), through the Middle Bronze Age (MBA; 1550–1150 BCE) and Late Bronze Age (LBA; 1150–750 BCE), to the pre-Roman Iron Age (IA; 750 BCE-43 CE). However, that study contained little data after 1300 BCE (Fig. 1). Today, however, EEF ancestry is significantly higher on average in southern Britain than in northern Britain, raising the question of when this increase occurred1,8. The rise in EEF ancestry cannot be explained by migration from northern continental Europe in the early medieval period, as early medieval migrants harboured less EEF ancestry than in Bronze Age Britain10 and hence would have decreased EEF ancestry instead of increasing it as we observe1. Fig. 1: Ancient DNA Dataset. Geographic distribution of sites and temporal distribution of individuals 4000 BCE-43 CE. Newly reported in black; published in orange. Base maps made with Natural Earth; elevation data Copernicus, European Digital Elevation Model v1.1. The Britain map labels sites harbouring ancestry outliers relative to others of the same period. The timeline shows archaeological periods in the British chronology: Neolithic (3950–2450 BCE), Chalcolithic and Early Bronze Age (C/EBA, 2450–1550 BCE), Middle Bronze Age (MBA, 1550–1150 BCE), Late Bronze Age (LBA, 1150–750 BCE), and pre-Roman Iron Age (IA, 750 BCE-43 CE). We add jitter on the Y axis and sample dates from their probability distributions (Supplementary Table 1). Box 1 Reconciling archaeological and genetic understandings of “migration” “Migration” is a central concept in both population genetics and archaeology, but its meaning has evolved in divergent ways in the course of the development of these disciplines27. Population geneticists use “migration” to refer to any movement of genetic material from one region to another which would see even low-level symmetrical exchanges of mates between adjacent communities as representing migration, while archaeologists restrict its use to processes that result in significant demographic change due to permanent translocation of people from one region to another28. In European archaeology, discussions of prehistoric migrations have become fraught due to the ways in which theories of migration were exploited politically in the early-mid twentieth century, when movement of large numbers of people over short times was sometimes argued to be a primary mechanism for the spread of ethnic groups and archaeological reconstructions of such events were used to justify claims on territory29. Because of this, some archaeologists prefer to set a high bar for theorizing migration, for example by restricting its use to cases where there is evidence for organized movements of people over a short time. However, this can make it difficult to recognize the important effects that large-scale movements of people had in prehistory28, such as the westward movement of people from the Steppe beginning in the third millennium BCE that genetic data have shown contributed much of the ancestry of later Europeans8,30. We use the term “migration” here with intention, because the movement of people into Britain we document was demographically transformative. We emphasize that our findings are not sufficient to prove mass movement over a short time; indeed our radiocarbon dating and isotopic evidence shows that at least some of the migration was drawn out over hundreds of years. www.ncbi.nlm.nih.gov/pmc/articles/PMC8889665/
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Post by Admin on Aug 26, 2023 19:58:32 GMT
We generated genome-wide ancient DNA data from 416 previously unanalysed individuals from Britain, increasing the number of pre-Roman individuals to 598 and multiplying by 28-fold the number from the combined period of the LBA and IA (from 13 to 365) (Fig. 1, Supplementary Information section 1, Supplementary Table 1, Methods). We also report data from ancient individuals mostly dating to the LBA and IA from the Czech Republic (n=160), Hungary (n=54), France (n=52), the Netherlands (n=28), Slovakia (n=25), Croatia (n=21), Slovenia (n=14), Spain (n=10), Serbia (n=8) and Austria (n=3). We increased data quality on 33 previously published individuals (Supplementary Table 1). To generate these data (Methods), we prepared powder from bones and teeth, extracted DNA, and generated 1020 sequencing libraries all pretreated with uracil-DNA glycosylase to reduce characteristic cytosine-to-thymine errors of ancient DNA (Supplementary Table 2). We enriched libraries in solution for a targeted set of more than 1.2 million single nucleotide polymorphisms (SNPs), sequenced them, then co-analysed with previously reported data (Supplementary Table 3). We clustered by time and geography aided by 123 newly reported radiocarbon dates (Supplementary Table 4). We separately labelled individuals that were significantly different in ancestry from the majority cluster from each time period and region (Supplementary Information section 2, Supplementary Table 5). Although we report data from all individuals, we removed a subset from the main analysis: those with evidence of contamination, those with a rate of damage in the final nucleotide lower than the typical range for authentic ancient DNA, those that were first degree relatives of other higher coverage individuals in the dataset, or those with too little data for accurate ancestry inference (<30,000 single nucleotide polymorphisms (SNPs) covered at least once) (Supplementary Table 5, Methods). Fig. 1 shows a map of analysed individuals. We identified 123 individuals from 48 families as related (within the third degree) to at least one other newly reported individual in the dataset (Supplementary Table 6). British ancient DNA time transect We computed f4-statistics with Block Jackknife standard errors11 between all pairs of temporal groupings of individuals in Britain, testing for differences in the rate of allele sharing (genetic drift) with the two major source populations (Steppe and EEF). We document a significant increase in the degree of allele sharing with EEF populations in England and Wales over the M-LBA and into the IA (Extended Data Table 1). To estimate the proportions of EEF, Steppe, and WHG ancestry, we used qpAdm12, which takes advantage of the fact that if a “Target” population is a mixture of “Source” populations for which we have close surrogates in our dataset, we can compute all possible f4-statistics relating the “Targets” and “Sources” to a set of chosen outgroups, and then use qpAdm to find the values of the mixture coefficients αEEF,αSteppe, and αSteppe that fit all the statistics, while also providing a p-value for whether the “Target” population can in fact be modelled as a mixture of close relatives of the “Sources”. We carefully chose our set of “Sources” and “Outgroups” to provide much more accurate inferences than previous qpAdm setups due to their large sample sizes and the high degree of leverage they provide for teasing apart the three major components of European ancestry (Supplementary Information section 2). Our proxies for the “Sources” are 22 early Balkan Neolithic farmers with minimal hunter-gatherer admixture (EEF), 20 Yamnaya and Poltavka pastoralists (Steppe), and 18 Mesolithic hunter-gatherers from across Western Europe (WHG). Our “Outgroups” are close genetic cousins of the three Sources—24 Anatolian Neolithic individuals related to EEF, 19 Afanasievo individuals related to Yamnaya Steppe pastoralists, and 41 hunter-gatherers largely from the Danubian Iron Gates related to WHG—and a pool of 9 ancient sub-Saharan Africans processed using the same in-solution enrichment technology and without evidence of West Eurasian-related admixture. EEF-related ancestry increased in England and Wales from 31.0±0.5% in the C/EBA (n=69), to 34.7±0.6% in the MBA (n=26), to 36.1±0.6% in the LBA (n=23), and stabilized at 37.9±0.4% in the IA (n=273) (here and below, we quote one standard error). There was no significant change in Scotland (Fig. 2 and Extended Data Table 1). Increased EEF ancestry was widespread in southern Britain by the IA, with point estimates ranging from 36.0–38.8% across eight regions of England (Wales sample sizes are too small to provide accurate inference) (Table 1, Extended Data Table 2). We considered the possibility that the rise in EEF ancestry in southern Britain was due to a resurgence of archaeologically less visible populations with more ancestry from people living in Britain in the Neolithic, which we missed either due to geographic biases in sampling, or variation across cultural contexts in the way groups treated their dead for example through cremation. However, models of IA people of England and Wales as a mixture of groups in Neolithic and C/EBA Britain failed at high significance (Extended Data Fig. 1). This is due to IA populations in Britain sharing alleles with some Neolithic populations in continental Europe that was not present in early Neolithic or C/EBA groups in Britain (Supplementary Information section 3). The most plausible explanation for these patterns is migration of people carrying this distinctive ancestry into southern Britain in the M-LBA. Fig. 2: Increase in EEF ancestry during the Middle to Late Bronze Age. EEF ancestry increased in southern Britain beginning with the Margetts Pit MBA outliers but hardly in the north. Estimates from qpAdm are binned into four archaeological periods. We plot means and one standard error from a Block Jackknife. Sample sizes in the C-EBA/MBA/LBA/IA are 69/26/23/273 in England and Wales and 10/5/4/18 in Scotland.
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Post by Admin on Aug 27, 2023 19:23:16 GMT
Table 1: Regional variation in ancestry in Iron Age Britain
Latitude Modeling Ancestry With Pre-Bronze Age Sources With Middle to Late Bronze Age Sources Region N P WHG EEF Steppe P Continental Scotland Orkney 2 59 0.22 14.2±1.1% 34.1±1.2% 51.6±1.6% 0.10 20±9% West 4 58 0.12 13.0±.8% 32.3±1.0% 54.7±1.2% 0.19 8±7% Southeast 12 56 0.67 12.1±.6% 33.9±.7% 54.0±.9% 0.39 16±5% England North 10 54 0.35 13.4±.6% 36.3±.8% 50.3±1.0% 0.76 35±5% E. Yorkshire 47 54 0.61 13.2±.4% 37.0±.5% 49.8±.6% 0.86 44±4% Midlands 18 53 0.66 12.6±.5% 36.0±.6% 51.4±.8% 0.77 36±4% Southwest 84 53 0.30 13.7±.4% 38.7±.4% 47.6±.6% 0.56 55±5% East Anglia 21 52 0.44 13.5±.5% 37.0±.5% 49.5±.7% 0.52 44±4% Southcentral 38 52 0.32 13.9±.4% 38.8±.5% 47.2±.6% 0.35 56±5% Southeast 3 51 0.13 13.9±.5% 38.3±.5% 47.8±.6% 0.40 52±5% Cornwall 16 50 0.40 13.5±.5% 36.4±.7% 50.1±.8% 0.64 39±5% Wales North 1 53 0.20 12.1±1.6% 34.7±2.0% 53.2±2.5% 0.53 22±14% South 2 51 0.66 14.2±1.2% 38.6±1.5% 47.2±1.8% 0.57 53±11%
Notes: Regions are ordered first by large grouping (Scotland-England-Wales), then latitude. We separate “England East Yorkshire” from “England North” because of distinctive cultural context in the IA (Arras). For the final two columns, we use as the Britain source Britain_C.EBA and as the continental source Margetts Pit / Cliffs End Farm pool.
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Post by Admin on Aug 28, 2023 18:31:06 GMT
We modelled ancestry in each individual, labelling significant ancestry outliers relative to most individuals of their period. We highlight key observations (Fig. 3, Extended Data Fig. 2). Fig. 3: By-individual analysis of the southern Britain time transect. (A) Estimates of EEF ancestry and one standard error for all individuals fitting a three-way admixture model (EEF + WHG + Yamnaya) at p>0.01 using qpAdm; we restrict to 2450 BCE-43 CE using the best date estimate from Supplementary Table 5. Most individuals are in blue, while significant outliers at the ancestry tails are in red (outliers are identified as p<0.005 based on a qpWave test from the main cluster from their period and |Z|>3 for a difference in EEF proportion, or p<0.1 and |Z|>3.5). We use a horizontal bar to show one standard error for the date (Supplementary Table 5). The black line shows population-wide EEF ancestry at each time obtained by weighting each individual’s EEF estimate by the inverse square of their standard error and the probability that their date falls at that time (based on the mean and standard error in Supplementary Table 5 assuming normality; we filter out individuals with standard errors >120 years). The incorporation of increased EEF ancestry into the majority of individuals occurred ~1000–875 BCE. (B) Proportion of outliers over 300-year sliding windows centered on each point, based on randomly sampling dates of all individuals 100 times assuming normality and their mean and standard deviation in Supplementary Table 5 (removing individuals with EEF errors >0.022 and date errors >120 years). Major epochs of migration into Britain are periods with elevated proportions of outliers: between 2450–1800 BCE (17% outliers) and 1300–750 BCE (17% again). The fact that there was an elevated rate of outliers prior to the 1000–875 BCE population-wide rise in EEF ancestry may reflect a delay between the time of arrival of migrants and their full incorporation into the population. First, replicating previous results8,9, we infer a cluster of Neolithic individuals from western Scotland with high WHG admixture, likely reflecting unions between recent migrants from Europe and descendants of local Mesolithic groups in Britain (Extended Data Fig. 2). Second, we infer high variability in EEF ancestry in the C/EBA, before EEF ancestry became relatively homogeneous after ~2000 BCE8 (Fig. 3). This is apparent at Amesbury Down where EEF ancestry in some burials is significantly below the average of 29.9±0.4% (e.g. I2417 at 22.2±1.8%), plausibly reflecting Beaker-period migrants who mixed with local Neolithic farmers to produce the intermediate EEF ancestry that prevailed by the end of the EBA. Others are above the group average including individual I14200 at 45.3±2.2%, known as the “Amesbury Archer,” who was buried in the most well-furnished grave recovered from the Stonehenge mortuary landscape and had an isotopic profile indicating that he spent parts of his childhood outside Britain, possibly in the Alps13. The fact that the Archer was a migrant but had too little Steppe ancestry to be from the population that drove Steppe ancestry to the level observed in C/EBA Britain, shows that Beaker-associated migrants to Britain were not genetically homogeneous. The ‘Companion’ (I2565), a burial found next to the Archer whose isotopic profile like most others at the site was consistent with a local upbringing, was not an ancestry outlier (32.7±3.0% EEF; Fig. 3). The Archer and the Companion shared a rare tarsal morphology and similar grave goods, hypothesized to reflect close genetic relationship (Supplementary Information section 4)14, but our results rule out first- or second-degree relatedness. Third, we observe four outliers with high EEF ancestry in the late MBA and LBA who are candidates for being first generation migrants or the offspring of recent migrants, all of whom were buried in Kent in the southeasternmost part of Britain. The earlier two are from Margetts Pit: 47.8±1.8% in individual I13716 (1391–1129 calBCE) and 43.6±1.8% in I13617 (1214–1052 calBCE). The latter two are from Cliffs End Farm: 43.2±2.0% in individual I14865 (967–811 calBCE) and 43.4±1.8% in I14861 (912–808 calBCE). We considered the possibility that we are observing the effect of a short burst of migration in the MBA which included the Margetts Pit outliers, followed by co-existence of separate communities with different EEF ancestry for at least a couple of hundred years, including the Cliffs End Farm outliers. However, strontium and oxygen isotope analyses identify multiple individuals of non-local origin at Cliffs End Farm15, including outlier I14861, suggesting that this was not a single mass migration but instead a stream of migrants over hundreds of years (Supplementary Information section 5). Fourth, the fraction of individuals whose ancestry is significantly different from the main group is 17% over the first part of the C/EBA (2450–1800 BCE), 4% from the end of the EBA through the beginning of the MBA (1800–1300 BCE), 17% from the end of the MBA through the LBA (1300–750 BCE), and 3% through the IA (Fig. 3). This is consistent with two periods of relatively high rates of migration into southern Britain in the Chalcolithic and then again in the M-LBA. We considered the possibility that our failure to observe a high rate of outliers in the IA compared with the preceding period was because ancestry had, by this time, homogenized to some extent between Britain and continental regions, which could make outliers more difficult to detect. However, average EEF ancestry in Britain in the IA was 37.9±0.4%, substantially different from much of contemporary Western and Central Europe—52.6±0.6% in Iberia, 49.8±0.4% in Austria, Hungary, and Slovenia, 45.4±0.5% in the Czech Republic, Slovakia and Germany, 45.6±0.5% in France and Switzerland, and 34.4±1.2% in the Netherlands (Fig. 4A)—which would have made the majority of migrants from these regions detectable given the <2% standard errors in most of our ancestry estimates (Supplementary Table 5). Our sampling from western France and Belgium is poor, and it is possible that EEF ancestry proportions there were similar to Britain, so we cannot rule out migration from this region in the IA. Nevertheless, our results are consistent with reduced migration from continental Europe and suggest a substantial degree of genetic isolation of Britain from much of continental Europe during the IA16.
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