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Thursday, September 17, 2015
Uralian genes
Below is a graph based on a couple of D-statistics. Note that out of the five Uralic-speaking groups, only Hungarians remain under the upward-sloping red line, clustering among Indo-European-speakers. On the other hand, the Indo-European-speaking Russians from Kargopol cluster with Uralic speakers. However, Russia is a complex affair in this context, because much of the north and east of European Russia was Uralic-speaking until very recently. The relevant D-stats are available here.
See also...
Ancient genomes from NE Europe suggest the tandem spread of Siberian admixture and Uralic languages into the region >3,500 ya
Sunday, September 13, 2015
ASHG 2015 abstracts
The abstract search is here. Feel free to post your picks in the comments. Lots of detail in this one, which is very much appreciated.
It has hitherto been difficult to obtain genome-wide data from the Near East. By targeting the inner ear region of the petrous bone for extraction [Pinhasi et al., PLoS One 2015] and using a genome-wide capture technology [Haak et al., Nature, 2015] we achieved unprecedented success in obtaining genome-wide data on more than 1.2 million single nucleotide polymorphism targets from 34 Neolithic individuals from Northwestern Anatolia (~6,300 years BCE), including 18 at greater than 1× coverage. Our analysis reveals a homogeneous population that is genetically a plausible source for the first farmers of Europe in the sense of (i) having a high frequency of Y-chromosome haplogroup G2a, and (ii) low Fst distances from early farmers of Germany (0.004 ± 0.0004) and Spain (0.014 ± 0.0009). Model-free principal components and model-based admixture analyses confirm a strong genetic relationship between Anatolian and European farmers. We model early European farmers as mixtures of Neolithic Anatolians and Mesolithic European hunter-gatherers, revealing very limited admixture with indigenous hunter-gatherers during the initial spread of Neolithic farmers into Europe. Our results therefore provide an overwhelming support to the migration of Near Eastern/Anatolian farmers into southeast and Central Europe around 7,000-6,500 BCE [Ammerman & Cavalli Sforza, 1984, Pinhasi et al., PLoS Biology, 2005]. Our results also show differences between early Anatolians and all present-day populations from the Near East, Anatolia, and Caucasus, showing that the early Anatolian farmers, just as their European relatives, were later demographically replaced to a substantial degree.
I. Lazaridis, D. Fernandes, N. Rohland, S. Mallick, K. Stewardson, S. Alpaslan, N. Patterson, R. Pinhasi, D. Reich, Genome-wide data on 34 ancient Anatolians identifies the founding population of the European Neolithic. ASHG 2015 abstract. Talk to be held on October 9.
See also...
The ancient DNA case against the Anatolian hypothesis
Monday, September 7, 2015
Copper & Bronze Age genomes from northern Spain
Update: the paper is now available and open access here.
See also: Yamnaya-related admixture in Bronze Age northern Iberia
...
A paper titled "Ancient genomes link early farmers from Atapuerca in Spain to modern-day Basques", by Günther et al., will appear shortly in PNAS early edition. Here's the press release from Uppsala University.
An international team led by researchers at Uppsala University reports a surprising discovery from the genomes of eight Iberian Stone-Age farmer remains. The analyses revealed that early Iberian farmers are the closest ancestors to modern-day Basques, in contrast previous hypotheses that linked Basques to earlier pre-farming groups.
The team could also demonstrate that farming was brought to Iberia by the same/similar groups that migrated to northern and central Europe and that the incoming farmers admixed with local, Iberian hunter-gather groups, a process that continued for at least 2 millennia.
The study is published today, ahead of print, in the leading scientific journal Proceedings of the National Academy of Sciences of the USA, PNAS.
Most of the previous studies about the transition from small and mobile hunter-gatherer groups to larger and sedentary farming populations have focused on central and northern Europe, however much less in known about how this major event unfolded in Iberia. This time, the research team investigated eight individuals associated with archaeological remains from farming cultures in the El Portalón cave from the well-known Anthropological site Atapuerca in northern Spain.
“The El Portalon cave is a fantastic site with amazing preservation of artefact material,” says Dr. Cristina Valdiosera of Uppsala University and La Trobe University, one of the lead authors.
“Every year we find human and animal bones and artifacts, including stone tools, ceramics, bone artefacts and metal objects, it is like a detailed book of the last 10,000 years, providing a wonderful understanding of this period. The preservation of organic remains is great and this has enabled us to study the genetic material complementing the archaeology,” Dr. Cristina Valdiosera continues.
From these individuals who lived 3,500-5,500 years ago, the authors generated the first genome-wide sequence data from Iberian ancient farmers and observed that these share a similar story to those of central and northern Europe. That is, they originate from a southern wave of expansion, and also admixed with local hunter-gatherer populations and spread agricultural practices through population expansions. The authors noticed that although they share these similarities with other European farmers, this early Iberian population has its own particularities.
“We show that the hunter-gatherer genetic component increases with time during several millennia, which means that later farmers were genetically more similar to hunter-gatherers than their forefathers who brought farming to Europe,” says Dr. Torsten Günther of Uppsala University and one of the lead authors.
“We also see that different farmers mixed with different hunter-gatherer groups across Europe, for example, Iberian farmers mixed with Iberian hunter-gatherers and Scandinavian farmers mixed with Scandinavian hunter-gatherers.” Dr. Cristina Valdiosera adds.
The study also reports that compared to all modern Spanish populations, the El Portalón individuals are genetically most similar to modern-day Basques. Basques have so far – based on their distinct culture, non-indo-European language, but also genetic make-up – been thought of as a population with a long continuity in the area, probably since more than 10,000 years ago.
“Our results show that the Basques trace their ancestry to early farming groups from Iberia, which contradicts previous views of them being a remnant population that trace their ancestry to Mesolithic hunter-gatherer groups,” says Prof. Mattias Jakobsson of Uppsala University, who headed the study.
“The difference between Basques and other Iberian groups is these latter ones show distinct features of admixture from the east and from north Africa.” he continues.
These findings shed light into the demographic processes taking place in Europe and Iberia during the last 5,000 years which highlights the unique opportunities gained from the collaborative work of archaeologists, anthropologists and geneticists in the analysis of ancient DNA.
“One of the great things about working with ancient DNA is that the data obtained is like opening a time capsule. Seeing the similarities between modern Basques and these early farmers directly tells us that Basques remained relatively isolated for the last 5,000 years but not much longer,” says Dr. Torsten Günther.
Source: Ancient genomes link early farmers to Basques
Wednesday, September 2, 2015
A multidimensional approach
This is arguably the most interesting Principal Component Analysis (PCA) I've run to date. Note that overall the ancient steppe genomes appear to be the crucial link in the Indo-European chain, basically bridging the gap between European and South Asian Indo-European-speakers. A plot with all of the samples labeled individually can be downloaded here. If you have any questions about the methodology, just ask in the comments.
In this analysis I used samples from the Allentoft et al., Haak et al. and Lazaridis et al. datasets, all of which are publicly available. The latter two are found at the Reich Lab site here.
See also...
No significant genetic substructures within (eastern) Yamnaya
Saturday, August 29, 2015
Children of the Divine Twins
The Trundholm sun chariot was found in a peat bog on the island of Zealand, Denmark, in 1902. It's thought to be an Indo-European religious artefact dating back to the Nordic Bronze Age; a representation of a horse pulling the sun and perhaps also the moon in a spoked wheel chariot. So one way or another it appears to be a reference to the Divine Twins mythos.
The Divine Twins are a key part of Indo-European religion, and they appear in the Rigveda, the most archaic of the Indo-Aryan Vedic texts.
However, because the concept includes the spoked wheel chariot, it probably can't be much older than 2,000 BC. That's because the invention of the spoked wheel chariot is more often than not credited to the Sintashta Culture of the Trans-Urals, which is dated to 2100-1800 BC.
Considering these cultural and technological ties between Bronze Age Scandinavia and South Asia, it's an interesting question whether there were also strong genetic links between these two outposts of the early Indo-European world.
Unfortunately, we don't yet have any ancient genomes from South Asia to compare to the Late Neolithic/Bronze Age (LN/BA) Nordic genomes published recently with Allentoft et al. 2015. However, we do have the Kalash.
The Kalash people of the Hindu Kush are Indo-Aryans, but they're also an extreme cultural and genetic isolate. It's likely that they haven't mixed very much with any of their neighbors since the Bronze Age. About half of them also practice a unique Vedic religion that celebrates the sun and moon (see section 1.5.4. "Creation myths" in Witzel 2002).
In the TreeMix analysis below I used three random Kalash individuals from the Human Origins dataset (HGDP00311, HGDP00313 and HGDP00315). I didn't run the whole set of 18 because they seem to create a genetic monolith that is impossible to break down and analyze correctly with TreeMix.
Note that after their Central Asian admixture is accounted for with a migration edge of 33%, the Kalash sit on what seems to be an early Indo-European branch that also includes the LN/BA Scandinavians. The full output from this analysis is available for download here.
I also employed the qpAdm software to model all of the Kalash from the Human Origins as a mixture of LN/BA Scandinavians, various ancient and present-day West Asians and Dai from south China. The ancestry proportions are listed at the bottom of the sheets. To check the success of the models consult the chisq, tail prob and standard (std.) errors.
Nordic LN-BA/Armenia BA/DaiNow, qpAdm is easy to run but very difficult to use correctly. However, even when fumbling around like a drunk with this software, it's easy to pick up some useful hints. Clearly, even if the ancestry proportions are way off, the Kalash show stronger affinity to the ancient Scandinavians than to West Asians. Also, the models more or less reflect the TreeMix analysis above.
Nordic LN-BA/Iranian/Dai
Nordic LN-BA/Iranian Jew/Dai
Nordic LN-BA/Georgian/Dai
Thus, the answer to my question is a resounding yes; there were indeed strong genetic ties between Scandinavia and South Asia during the Bronze Age.
See also...
The Poltavka outlier
The mystery of the Sintashta people
The real thing
Monday, August 24, 2015
Pre- and Post-Kurgan Europe
The Principal Component Analysis (PCA) below is based on four sets of D-statistics. The second image shows what they are and how they affect the components. The datasheet is available here. If you don't know what EHG, SHG and WHG stand for, see here.
Note that the post-Kurgan Europeans are shifted east, towards the Bronze Age steppe groups (most of which are in fact classified as Kurgan cultures), relative to the pre-Kurgan Europeans. Coincidence? Certainly not. Interestingly, the West Asians show a similar shift to the east, although it's not yet clear who caused it and when.
In this analysis I used samples from the Allentoft et al., Haak et al. and Lazaridis et al. datasets, all of which are publicly available. The latter two are found at the Reich Lab site here.
Update 12/09/2015: Matt posted these graphs in the comments. The first graph shows Yamnaya-related ancestry proportions for a series of points along the Yamnaya-Middle Neolithic continuum, which can be used to estimate Yamnaya-related admixture in samples that cluster near these points.
See also...
Smarter than the average bear
Smarter than the average bear
Using a few ancient hunter-gatherer sequences, formal statistics, and enough present-day samples, I can predict with basically 100% accuracy whether an ethnic group is of European or extra-European origin. Actually, there's probably an infinite number of ways of doing the same thing nowadays, but I thought this was an effective way of visualizing it. The datasheet can be downloaded here.
I also tried to analyze the Indo-European expansion in a similar way. The results are a lot less obvious, and there are a number of reasons for this. One of the main factors, I'd say, is that languages can be learned or imposed very quickly, and this happened often during historic times, well after the Proto-Indo-European dispersals.
For instance, Sardinians spoke Paleo-Sardinian or Nuragic languages until they adopted Indo-European speech, in the form of Latin, from the Romans (see page 118 here). Indeed, it's highly unlikely that any Proto-Indo-Europeans ever stepped foot on Sardinia. The relevant datasheet is here.
In this analysis I used samples from the Allentoft et al., Haak et al. and Lazaridis et al. datasets, all of which are publicly available. The latter two are found at the Reich Lab site here.
See also...
Pre and Post-Kurgan Europe
Wednesday, August 19, 2015
No significant genetic substructures within (eastern) Yamnaya
It's interesting and perhaps important that there's practically no difference between the two sets of Yamnaya samples published to date, despite the fact that they're from regions separated by ~1,000 kilometers. Yamnaya_Rise is from between the Black and Caspian seas, while Yamnaya_Haak from just north of the Caspian.
Note the lack of significant Z scores (around 3 or more) in these D-stats. Although the almost significant Z score with Loschbour, a Mesolithic Western Hunter-Gatherer (WHG) from Luxembourg, does look somewhat curious.
It's difficult to know what all of this means exactly without seeing any ancient samples from archaeological cultures that preceded Yamnaya on the Pontic-Caspian Steppe. However, it could mean that the Yamnaya nomads arrived north of the Caspian from the south, which is also what preliminary Y-chromosome data is hinting at (see here).
Yamnaya was succeeded northeast of the Caspian by its offshoot, the Poltavka Culture, which in turn was replaced by the Sintashta Culture. The most widely accepted theory, based on archaeological data, is that Sintashta formed from a chain of cultures derived from the late Corded Ware horizon of East-Central Europe. This is backed up by the D-stats below, which suggest some western admixture in Sintashta that is missing in Yamnaya.
In this analysis I used samples from the Allentoft et al. (Rise Project), Haak et al. and Lazaridis et al. datasets, all of which are publicly available. The latter two are found at the Reich Lab site here.
See also...
A multidimensional approach
Tuesday, August 18, 2015
Warfare and torture in the last years of the LBK
More than half of the 26 victims of an apparent ambush on a Linear Pottery (LBK) village in Neolithic Germany had their legs broken. The archaeologists studying the site think it was either torture or ritual mutilation. Also note the lack of young women in the death pit. They were probably kidnapped. The paper is behind a pay wall, but there's a news feature on the findings here.
Abstract: Conflict and warfare are central but also disputed themes in discussions about the European Neolithic. Although a few recent population studies provide broad overviews, only a very limited number of currently known key sites provide precise insights into moments of extreme and mass violence and their impact on Neolithic societies. The massacre sites of Talheim, Germany, and Asparn/Schletz, Austria, have long been the focal points around which hypotheses concerning a final lethal crisis of the first Central European farmers of the Early Neolithic Linearbandkeramik Culture (LBK) have concentrated. With the recently examined LBK mass grave site of Schöneck-Kilianstädten, Germany, we present new conclusive and indisputable evidence for another massacre, adding new data to the discussion of LBK violence patterns. At least 26 individuals were violently killed by blunt force and arrow injuries before being deposited in a commingled mass grave. Although the absence and possible abduction of younger females has been suggested for other sites previously, a new violence-related pattern was identified here: the intentional and systematic breaking of lower limbs. The abundance of the identified perimortem fractures clearly indicates torture and/or mutilation of the victims. The new evidence presented here for unequivocal lethal violence on a large scale is put into perspective for the Early Neolithic of Central Europe and, in conjunction with previous results, indicates that massacres of entire communities were not isolated occurrences but rather were frequent features of the last phases of the LBK.
Meyer et al., The massacre mass grave of Schöneck-Kilianstädten reveals new insights into collective violence in Early Neolithic Central Europe, Published online before print August 17, 2015, doi: 10.1073/pnas.1504365112
Sunday, August 16, 2015
D(Outgroup, PopTest) (Pop1, Pop2)
I ran these tests using 65-112K transversion sites, so the results should be very solid. The spreadsheet is here. My impression is that MA1-related (ANE?) ancestry was present in South Central Asia before R1a-Z93 steppe people moved into the area during the Bronze Age. Any thoughts?
All of the samples are from the recent Allentoft et al. and Haak et al. papers, available on request from the authors and here, respectively.
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