Yersinia pestis, the etiologic agent of plague, is a bacterium associated with wild rodents and their fleas. Historically it was responsible for three pandemics: the Plague of Justinian in the 6th century AD, which persisted until the 8th century [ 1 ]; the renowned Black Death of the 14th century [ 2, 3 ], with recurrent outbreaks until the 18th century [ 4 ]; and the most recent 19th century pandemic, in which Y. pestis spread worldwide [ 5 ] and became endemic in several regions [ 6 ]. The discovery of molecular signatures of Y. pestis in prehistoric Eurasian individuals and two genomes from Southern Siberia suggest that Y. pestis caused some form of disease in humans prior to the first historically documented pandemic [ 7 ]. Here, we present six new European Y. pestis genomes spanning the Late Neolithic to the Bronze Age (LNBA; 4,800 to 3,700 calibrated years before present). This time period is characterized by major transformative cultural and social changes that led to cross-European networks of contact and exchange [ 8, 9 ]. We show that all known LNBA strains form a single putatively extinct clade in the Y. pestis phylogeny. Interpreting our data within the context of recent ancient human genomic evidence that suggests an increase in human mobility during the LNBA, we propose a possible scenario for the early spread of Y. pestis: the pathogen may have entered Europe from Central Eurasia following an expansion of people from the steppe, persisted within Europe until the mid-Bronze Age, and moved back toward Central Eurasia in parallel with human populations.
It seems that, notwithstanding the simplistic (white) arrows of steppe ancestry expansion shown in their map (see below), the actual expansion of Yersinia pestis might have in fact accompanied Yamna migrants from the Pontic-Caspian steppe into Early Bronze Age cultures from the Balkans, including Bell Beaker migrants, as the phylogenetic analysis and dates suggest – and as the potential arrows of the plague expansion in the map (in green) show.
Instead of warring nature, close ties, and mobility of Corded Ware peoples (reasons I used to justify the rapid spread of the disease among CWC groups), I guess it was rather the higher population density of SE Europecompared to the regions north of the loess belt, as well as the greater admixture of Yamna migrants with native SE European populations, the factors which might have helped expand the disease.
Nevertheless, lacking more data, it is unclear if the disease expanded with both steppe groups.
A popular science article on Indo-European migrations has appeared at Science News, entitled How Asian nomadic herders built new Bronze Age cultures, signed by Bruce Bower. While the article is well-balanced and introduces new readers to the current status quo of the controversy on Indo-European migrations – including the opposing theories led by Kristiansen/Anthony vs. Heyd – , it reverberates yet again the conclusions of the 2015 Nature articles on the subject, especially with its featured image.
Corded Ware culture emerged as a hybrid way of life that included crop cultivation, breeding of farm animals and some hunting and gathering, Kristiansen argues. Communal living structures and group graves of earlier European farmers were replaced by smaller structures suitable for families and single graves covered by earthen mounds. Yamnaya families had lived out of their wagons even before trekking to Europe. A shared emphasis on family life and burying the dead individually indicates that members of the Yamnaya and Corded Ware cultures kept possessions among close relatives, in Kristiansen’s view.
“The Yamnaya and the Corded Ware culture were unified by a new idea of transmitting property between related individuals and families,” Kristiansen says.
Yamnaya migrants must have spoken a fledgling version of Indo-European languages that later spread across Europe and parts of Asia, Kristiansen’s group contends. Anthony, a longtime Kristiansen collaborator, agrees. Reconstructed vocabularies for people of the Corded Ware culture include words related to wagons, wheels and horse breeding that could have come only from the Yamnaya, Anthony says.
I have already talked about Kristiansen’s continuation of Gimbutas’ outdated ideas: we are seeing a renewed effort by some Scandinavian (mainly Danish) scholars to boost (and somehow capitalise) the revitalised concept of the “Kurgan people”, although now the fundamental issue has been more clearly shifted to the language spoken by Corded Ware migrants.
I think he is thus showing a great deal of restraint, not jumping on the bandwagon of this recent trend based on scarce genetic finds – and therefore losing also the opportunity to publish articles in journals of high impact factor….
This newly created Danish school, on the other hand, seems to be swimming with the tide. Kristiansen, known for his controversial ‘universal’ interpretations of European Prehistory – which are nevertheless more readable and interesting than most specialised literature on Archaeology, at least for us non-archaeologists – , has apparently seized the opportunity to give a strong impulse to his theories.
Not that there is nothing wrong with that, of course, but sometimes it might seem that a lot of papers (or even researchers) support something, when in fact there are only a few of them, working closely together…
I see therefore three main “branches” of this support (two of them, Genetics and Linguistics, only recently giving some limited air to this dying hypothesis), with a closely related group of people involved in this model, and they are lending continuous support to each other, by repeating the same theory – and repeating the same misleading map images (like the one shown in the article) – , so that the circular reasoning they represent is concealed behind seemingly independent works.
After this proposal, there are mostly just his publications supporting this model. Nevertheless, Kristiansen’s model, I gather, did not involve the sudden Yamnaya -> Corded Ware migrations discussed in recent genetic articles, but long-lasting contacts between peoples and cultures from the North Pontic steppe, Trypillian, and Globular Amphora, that formed a new mixed one, the Corded Ware people and culture. Also, in Gimbutas’ original model of migration (1963), waves of Kurgan migrants are also described into Vučedol and Bell Beaker, which have been apparently forgotten in recent models*.
* The most recent model by Anthony describes such migrations into Early Bronze Age Balkan cultures – as do most archaeological publications today – , but he is unable to recognize migration waves from Yamna into the Corded Ware culture, and because of that describes mere potential routes (or modes) of cultural diffusion including language change.
This recently created Danish pressure group is not something bad per se. I don’t agree with their hypothesis (or rather evolving hypotheses, since they change with new genetic results and linguistic proposals, as is shown in Kristiansen et al. 2017), but I understand that the group continues a recent tradition:
Publications are always great to advance in knowledge, and if they bring some deal of publicity, and more publications (with the always craved impact factor), and maybe more investment in the departments (with more local jobs and prestige)… why not?
However, this model of workgroup research system is reminiscent of the Anatolian homeland group loosely created around Renfrew; the Palaeolithic Continuity workgroup around Cavalli-Sforza; or (more recently) the Celtic from the West group around Cunliffe and Koch. The difference between Kristiansen’s workgroup and supporters of all those other models, in my opinion, is that (at least for the moment) their collaboration is not obvious to many.
Therefore, to be fair with any outsider, I think this group should clearly state their end model: I propose the general term “Indo-European Corded Ware Theory” (IECWT) workgroup, because ‘Danish’ is too narrow, and ‘Scandinavian’ too broad to represent the whole group. But any name will do.
Not for a solid model of PIE expansion from Corded Ware, not even within the IECWT group, where there is no support (to date) for a Balto-Slavic expansion associated with the Corded Ware culture… Or any other dialect, for that matter;
Not for a unified Pre-Germanic community before the Dagger Period, and still less linked with the expansion of the Corded Ware culture from the steppe – that connection is found only in Anthony (2007), where he links it with a cultural diffusion into Usatovo, which seems too late for a linguistic expansion with Corded Ware peoples, with the current genetic data.
However, a lot of people are willing to consume post-truth genetic-based citebait like crazy, in a time when Twitter, Facebook, blogs, etc. seem to shape the general knowledge, while dozens of new, carefully prepared papers on Archaeology and Linguistics related to Indo-European peoples get published weekly and don’t attract any attention, just because they do not support these simplistic claims, or precisely because they fully reject them.
An older connection of Germanic to Scandinavia – and thus an ancestral Indo-European cultural diffusion from north to south – seems to better fit the traditional idea of an autochthonous Germanic homeland in Scandinavia, instead of a bunch of southern Bell Beaker invaders bringing the language that could only later develop as a common Nordic language during the Bronze Age, in a genetically-diverse community…
One is left to wonder whether the support of Corded Ware + haplogroup R1a representing Pre-Germanic is also in line with the most natural human Kossinnian trends, whereby the older your paternal line and your ancestral language are connected to your historical territory, the better. The lack of researchers from Norway – where R1b subclades brought by Bell Beakers peak – in the workgroup is revealing.
It is not intended to be against these researchers individually, though. All of them have certainly contributed in great ways to their fields, indeed more than I have to any field: Kristiansen is well-known for his careful, global interpretations of European prehistory (and has been supporting his model for quite a long time). I do like Kroonen’s ideas of a Pre-Germanic substratum. And people involved in the group do so probably because they collaborate closely with each other, and because of the huge pressure to publish in journals of high impact factor, so to mix their disparate research within a common model seems only natural.
But their collaboration is boosting certain wrong ideas, and is giving way to certain misconceptions in Linguistics, and also sadly renewed past ethnocentric views of language in Northern Europe – that will be luckily demonstrated, again, wrong. After all, publications (like ideas in general) are subjected to criticism, as mine are. Researchers who publish know their work is subjected to criticism, and not only before publication, but also – and probably more so – after it. That a paper can be incorrect, biased, or even completely absurd, does not mean the person who wrote it is a fool. That’s the difference between criticising ideas and insulting. If criticism offends you, you shouldn’t be publishing. Period.
Human ancestry can only help solve anthropological questions by using all anthropological disciplines involved. I have said that many times in this blog.
Correlation does not mean causation
Really, it does not.
You might think the tenet ‘correlation does not mean causation‘ must be evident at this point in Statistics, and it must also be for all those using statistical methods in their research. But it is sadly not so. A lot of researchers just look for correlation, and derive conclusions – without even an initial sound hypothesis to be contrasted… You can judge for yourself, e.g. reading the many instances of this complaint in recent publications of Biomedical and Social Sciences, on the interesting blog Statistical Modeling, Causal Inference, and Social Science.
In anthropological questions regarding Indo-European studies there is an added handicap: not taking correlation to mean causation does also mean – to avoid at least the most obvious confounders – taking into account the multiple linguistic and archaeological data that are available right now, to explain the expansion of Indo-European languages.
You might also believe that international researchers in Human Evolutionary Biology – after all, this is essentially a biomedical discipline – are acquainted with statistical methods and their problems when applied to their field. And that scientific journals – and especially those with the highest impact factors, like Nature, Science, or PNAS – have professional, careful reviewers who would never accept papers that equal correlation with causation, especially when Social Sciences are involved (because this alone might make errors grow exponentially…). Sadly, this is obviously not so, either.
Both studies [Haak et al. (2015) and this one] found a genetic affinity between samples from a central European culture known as Corded Ware, which existed from around 2500 bc, and samples from the earlier Yamnaya steppe culture. This similarity between distant populations is best explained by a substantial westward expansion of the Yamnaya or their close relatives into central Europe (Fig. 1b). Such an expansion is consistent with the steppe hypothesis, which argues that Corded Ware cultures were a conduit for the dispersal of Indo-European languages into Europe.
More interesting than these vague words – and the short, almost invisible suggestion that Yamna may not be exactly the population behind Corded Ware peoples – are the maps that illustrated in Nature their risky hypothesis: they called it “steppe hypothesis“, like that (in general terms), as if everyone defending a steppe origin for Proto-Indo-European would support such a model, when they actually referred to the specific hypothesis of one of their authors (Kristiansen), one of the few archaeologists who keep Gimbutas’ concept of the ‘Kurgan peoples’ alive, based on the Corded Ware culture:
In many publications that followed, the trend has been to reproduce this graphical model, by asserting (or implying) that Bell Beaker peoples were the result of subsequent Corded Ware migrations, and indeed that Corded Ware peoples migrated from the Yamna culture, and were thus the vector of expansion for Indo-European languages in Europe.
We shall see then just a rather surreptitious shift in terminology from ‘Yamnaya’ to ‘steppe’ component, to adapt to the new data – i.e. some damage control while the ship of ‘Yamnaya ancestry’ capsizes – but little else. “Earlier ‘Yamnaya ancestry’, you say? Just, you know, let’s call it ‘steppe ancestry’ and shift the expansion of Indo-European languages to one or two thousand years earlier, and done!”
The damage of this post-truth genetics is already done: we will see the unending distribution on the Internet in general, and on social networks in particular, of these grandiose conclusions, of far-fetched Indo-European migration models that include the Corded Ware culture, of simplistic maps with apparently harmless ‘arrows of migration’ (like the above) representing fictional population movements suggesting nonexistent dialectal branches.
You might be one of those sceptics wary of so many boring statistical rules: “But it’s a safe reasoning: Yamanaya samples have an ‘ancestral component’ that is found elevated in Corded Ware samples, and less so in Bell Beaker samples, and PCA showed a similar result…so the migration model Yamnaya -> Corded Ware -> Bell Beaker is a priori correct, right?”
The ‘Future American’ hypothesis
Let me illustrate this attractive “Correlation = Causation” argument, using it to solve the problem of Future American languages.
Suppose we live in a future post-apocalyptic world ca. 3500 AD, with no surviving historical records before 3000 AD. None. Just investigation of cultures and their relationship by Archaeology, proto-languages reconstructed and language families identified by Linguistics, etc.
We have thus Future Germanic and Future Romance as the only language families spoken in Future Western Europe and in the Future Americas, in a distribution similar to the present day*, and we have certain somehow related archaeologically-defined cultures on both sides of the Atlantic, like Briton, Iberian, Norman, or Lowlandish, although their distribution remains partly undefined in time and space.
* If you are really curious about this scenario, you can read about the potential evolution of a Future North-American language.
But what languages did the ancestors of Future Americans speak, and who spread them? That question remains far from being settled by our future researchers, in spite of the solidest linguistic and migration models (talking mainly about Briton and Iberian cultures): too many authorities out there questioning them, fighting to impose their own pet theories.
Suddenly, the newly developed field of Human Ancestry comes to save the day. So let’s say we have this map of ancient samples recovered (dated from, say, the 6th to the 18th century AD), and our study is centered on the newly described “Western European” component (a precise combination of, say, WHG+steppe), which peaks in early samples from the Low Lands – hence we call it, quite daringly, “Lowlandic component“.
Our group is keen to demonstrate that the ancient Lowlandic culture described in Archaeology (marked especially by the worldwide distribution of tulips among other traits) is the origin of Western European and American languages… Now, let’s reach conclusions about migrations in the Middle Ages!
PCA shows that South-West European samples cluster closely to some North-West European samples, and that some late South American samples available cluster at some distance from North American samples – nearer to a native component represented by two individuals with 0% Lowlandic ancestry and a different cluster in PCA. And some North-American samples cluster quite closely to North-West European samples.
Based on the decrease in ‘Lowlandic component’ in the different samples and on PCA, we conclude that Lowlandic peoples (“or their close relatives”) must have migrated at the same time to North America, South America (or potentially from North America to South America?) as well as western, central, and northern Europe. Both migration events must have happened roughly at the same time, in part because both distinct language families appear in a north-south distribution, and Proto-Lowlandic must be (according to Genetics) the ancestor of both, Proto-Future-Germanic and Proto-Future-Romance.
That makes a lot of sense! A huge Lowlandic pressure for migration, you see. Push-pull mechanisms and stuff. A Lowlandic Empire probably (scattered remains are found everywhere)! And, judging by the presence of the ‘Lowlandic component’ in Future East Europe from the Elbe to the Vistula, maybe Lowlandic peoples spread Proto-Slavic, too! We can even date the common Lowlandic-Slavic proto-language this way! So many groundbreaking conclusions!
Future scholars supporting the Lowlandic homeland are on fire; they can’t get enough of publishing papers on the subject. “Two different Future American language families with cultural origins in Britain and Iberia, my ass! Because genetics.”
And don’t forget the future people of haplogroup R1b-U106 and high Lowlandic component: Wow, they are the heirs of those who expanded Future Germanic and Future Romance languages everywhere, aren’t they? How proud they must be. And who wouldn’t want to have these tall, blond, blue-eyed Lowlanders as their forefathers? Personalised genetic analysis is selling like crazy: “let’s know our Lowlandic percentage!”. Everyone is happy, colourful maps with lots of arrows and shit…
But – your future you might ask in awe, seeing that this doesn’t sound quite right, based on your basic archaeological and linguistic knowledge:
What about specific models of migration proposed to date? The solidest ones, not just anyone that seems to fit?
What about the dialectal classification of languages? The mainstream ones, not those that are compatible with this interpretation?
What about archaeological cultures to which individual samples belonged?
What about the actual dates of each sample? And how this date relates to the state of the culture to which it belongs?
What about the haplogroups, and the actual subclade of each haplogroup?
What about the territories, cultures, and dates not sampled, could they change this interpretation in light of known archaeological models?
And what about the actual origin of that ancestral component they so frivolously named? Dit it really appear ex nihilo in the Low Lands, and expanded from it?
“Who cares! This new data is sooo coool… And it proves what we wanted, what a coincidence! And it’s numbers, mate! Numbers don’t lie.”
The recording is available as audio (see above) or video (see below) with captions and multiple subtitles. The captions in North-West Indo-European show acute accents over accented vowels, while stressed syllables are underlined:
I think such a recording was necessary for comparison with the most commonly reconstructed pronunciation, as taught usually in courses. And I am not referring to those professors still using only stress – instead of pitch – accent to pronounce PIE, but to those that, using pitch accent, do place stress over the same syllable.
Apart from some controversial decisions regarding the Proto-Indo-Hittite reconstruction – see our explanation of our version, or e.g. Kortlandt’s reconstruction of the Fable (PDF) for more details – , his recitation does not seem to contrast enough pitch and stress accent, to the extent that pitch and stress seem to be always on the same syllable. He specialises in Proto-Indo-European phonology, so maybe it is a voluntary selection.
Firstly, as an introduction – in case you don’t know anything about this question -, a pitch accent is reconstructed for Proto-Indo-European, based on the reconstructed accent of Old Indian, Greek, Germanic, and Balto-Slavic – hence also valid for North-West Indo-European, even though Italo-Celtic lost it completely.
If you have listened to any tonal language*, words have also stress accent, and not necessarily on the same syllable – but usually on the heaviest one. In fact, I don’t know of an accent pattern with pitch+stress on the same syllable (but for certain reconstructed intermediate labile stages of a languages), and I guess it is so redundant that it would always lose one of them.
*pitch-accent systems are also tonal systems, after all, since they involve at least two tones: an acute or rising one, and usually a falling one after it.
You can listen to a sample of the Homeric recitation by Stephen Daitz, with restored Ancient Greek pronunciation, where he contrasts pitch and stress beautifully:
To see what I mean with the lack of contrast in Byrd’s pronunciation, just compare the restored pronunciation with these samples, of restored Koine Greek, from the Biblical Language Center. I think you can hear pitch accent pronounced, but always stressing the same syllable. After a while, it gets quite monotone (no pun intended); for me, at least*.
Pitch accent in my pronunciation is not as noticeable as that of Stephen Daitz, and still less than that of Stefan Hagel. But it is not intended to.
I wanted to combine tone and stress as naturally as possible, as it is found in modern languages, like Chinese, or like South Slavic, Baltic, or Scandinavian languages. I believe PIE phonology cannot be too different from modern natural examples.
Many Modern Greek scholars complain about the artificiality of the restored pronunciation. I’ve heard particularly harsh criticism against Stefan Hagel’s pronunciation: many scholars do not recognise the ancestral language in the restored pronunciation.
While such critics may seem like snob reactionaries, and I really appreciate an exaggerated poetic style for epic poems (I have spent hundreds, probably thousands, of hours listening to Stephen Daitz), I don’t think this is the way Ancient Greek was usually spoken. Listening to Hagel’s pronunciation in the Ancient Greek Assimil, there is a huge contrast between readers who don’t use the restored pronunciation in the recordings (offering thus a decaffeinated Ancient Greek), and Hagel’s reading (or, almost, singing).
In my interpretation of the fable I have tried to follow these ideas, and maybe in the end the pitch accent is not as acute as it should be (a fifth higher). On the other hand, it seemed more natural to me this way.
Also, in the final version of my reading, there are many words where it is not clear – not even to me – if there is more than one syllable with pitch or stress accent. This is especially so after after my first change of voice to make a more acute ‘sheep voice’, and then worsens with my graver ‘horse voice’. I really thought recording this was going to be easier!
If you have any comments or suggestions on the pronunciation, they are all welcome.
UPDATE (November 2, 2017): Frederik Kortlandt comments our paper – “When comparing PIE with other tonal languages, the best candidate is Japanese, which means that the “stress” falls on the last High syllable of a word form or sequence of connected word forms.”
Fernando López-Menchero and I have published our first draft on the North-West Indo-European proto-language. Our contribution concerns mainly phonetics, and namely two of its most controversial aspects: a common process of laryngeal loss and two series of velars for PIE.
There is also an updated linguistic model for the Corded Ware substrate hypothesis, which seeks to explain certain similarities between Germanic and Balto-Slavic, and between Balto-Slavic and Indo-Iranian, and potential isoglosses between the three.
As you probably know, our interest is (and has been for the past 15 years or so, even before our common project) the reconstruction of a North-West Indo-European proto-language, the ancestor of Italo-Celtic, Germanic, and Balto-Slavic. At least since Krahe’s proposal of an Alteuropäische substrate to European hydronymy, some 70 years ago, Indo-Europeanists have been supporting an Old European branch of Proto-Indo-European.
However, dialectal divisions were tentative. Since Oettinger, some 30 years ago, we have a clearer picture of a group of closely related dialects, namely Italo-Celtic, Germanic, and Balto-Slavic. Although the nature of Balto-Slavic is somehow contended (for the few scholars who support an Indo-Slavonic group), the minimalist view holds that at least the substrate language of Baltic and Slavic, Holzer‘s Temematic, was part of the North-West Indo-European group.
A North-West Indo-European (NWIE) proto-language not only solved the controversial question of Pan-European IE hydronymy (clearly of Late Indo-European nature), but also – and more elegantly – the question on the origin of the many fragmentary languages attested in Western Europe, usually attributed to a “Pre-Celtic” or “Pre-Italic” nature depending on their surrounding languages (Venetic has even said to be related to Germanic…).
Described first mainly in terms of lexical isoglosses, the concept of a NWIE language was then gradually and strongly founded in common grammatical features, contributed to mainly by the German, North American, and Spanish schools (as you know, the British or French schools are quite divided on the nature of Proto-Indo-European itself…). Recent archaeological models pioneered by Harrison and Heyd (2007) showed how this might have happened, with Yamna migrants that evolved as the East Bell Beaker group, and their subsequent expansion into most of Europe.
This traditional model of a ‘Corded Ware -> Bell Beaker expansion of NWIE’ which we also followed until recently, never fit well with the known migrations paths from Yamna (into Balkan Early Bronze Age cultures), with the geographic distribution of Old European hydronymy, or with the guesstimates for Late Indo-European and North-West Indo-European. This compelled us to support a break-up of the proto-language further back in time than warranted by models of language change, and it needed certain unlikely cultural diffusion events over huge areas (because no such migration from Yamna to northern Europe has been attested): along the steppe/forest-steppe zone first, for a diffusion from Yamna into Corded Ware cultures, and along the Danube or the Rhine later, for a diffusion of Corded Ware into Bell Beaker. These models were also based on the wrong interpretation of the first radiocarbon dates of Beakers – placing an origin of the Bell Beaker people in Iberia (which has been rejected in Archaeology, and now also in Genetics).
Such a ‘Germano-Balto-Slavic’ group faded in Linguistics long ago, with most Indo-Europeanists preferring to talk about late contacts (viz. Celto-Germanic or Italo-Germanic contacts), and for some there is – if any subgroup at all – a core West Indo-European or Italo-Celto-Germanic group, which may be supported by recent genetic research on Bell Beaker peoples, with the Beaker group of the Netherlands being the key. Our research on the potential language spoken by Corded Ware peoples – most likely related to Uralic, from an Indo-Uralic community from the Pontic-Caspian steppe – can elegantly explain the isoglosses that both European dialects share.
Included is my first sketch of the genetic history of Europe, as I interpret it in light of Genetic research (especially from outputs of qpGraph published to date), but also Archaeology (and, to some extent, Linguistics).
I have also taken this opportunity to upload some drafts I had been preparing in September while working on the Third Edition, that I have sadly not been able to complete as I would have wanted to. The drafts are posted in the section Human Ancestry. I post them as they are, in the hope that they can help others.