Modern domestic horses came from the Eastern European steppe

Over at Nature at this LINK. I'm getting the impression that geneticists and the editors at Nature are really crap at geography. Obviously, this paper argues that modern domestic horses came from the Pontic-Caspian steppe, which is located very firmly in Eastern Europe. But, inexplicably, instead of actually saying this, the authors came up with the much more ambiguous term Western Eurasian steppes, and even put that in the title. I wonder why? Here's the paper abstract:

Domestication of horses fundamentally transformed long-range mobility and warfare 1. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling 2,3,4 at Botai, Central Asia around 3500 bc3. Other longstanding candidate regions for horse domestication, such as Iberia 5 and Anatolia 6, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes [my note: they actually mean the Pontic-Caspian steppe, which is located in Eastern Europe], especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association 7 between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe [my note: the Yamnaya culture was located in Europe] around 3000 bc 8,9 driving the spread of Indo-European languages 10. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture 11,12.

Librado, P., Khan, N., Fages, A. et al. The origins and spread of domestic horses from the Western Eurasian steppes. Nature (2021). https://doi.org/10.1038/s41586-021-04018-9

Update: I emailed one of the lead authors, Ludovic Orlando, asking him for a comment. Here it is:

Thanks for your interest in our research. We indeed struggled finding the term that would be most appropriate and this was discussed with our coauthors. The Pontic-Caspian steppe would seem the most obvious choice but my understanding is that this would include a large region, stretching from the most north-western side of the Black sea to the foothills of the Urals. This is larger than the signature recovered in our data. My understanding is that the Eastern European steppes would also stretch more northernly than the region that we narrowed down. Eastern European steppes was also not immediately clear, even for European scholars such as myself. Therefore, it did not seem that there were any terms that were ready-made for truly qualifying our findings. We thus went for Western Eurasian steppes in the main title, and sticked to more precise locations such as the Don-Volga region in the main text. I guess that this is one of those cases where the activities of past herders did not exactly follow some geographic terms that would only be defined thousands of years later.

However, the Pontic-Caspian steppe and the Eastern European steppe are in fact terms that describe the western end of the Eurasian steppe. So they should be totally interchangeable with the term Western Eurasian steppes. Except, at least to me, they seem less ambiguous.

Ergo, the Eastern European steppe can't be more northerly than the Western Eurasian steppes, because it's the same thing. Moreover, the Pontic-Caspian steppe can't stretch further west than the Western Eurasian steppes, because, again, it's the same thing.

Indeed, the land north of the Eastern European/Western Eurasian steppes is called the forest steppe.

See also...

Yamnaya people drank horse milk (Wilkin et al. 2021)

Over at Nature at this LINK. I'm guessing the claim that Yamnaya pastoralists lived in Scandinavia is a huge typo. Obviously, the authors are referring to the people of the Corded Ware culture (CWC). From the paper:

During the Early Bronze Age, populations of the western Eurasian steppe expanded across an immense area of northern Eurasia. Combined archaeological and genetic evidence supports widespread Early Bronze Age population movements out of the Pontic–Caspian steppe that resulted in gene flow across vast distances, linking populations of Yamnaya pastoralists in Scandinavia with pastoral populations (known as the Afanasievo) far to the east in the Altai Mountains1,2 and Mongolia3. Although some models hold that this expansion was the outcome of a newly mobile pastoral economy characterized by horse traction, bulk wagon transport4,5,6 and regular dietary dependence on meat and milk5, hard evidence for these economic features has not been found. Here we draw on proteomic analysis of dental calculus from individuals from the western Eurasian steppe to demonstrate a major transition in dairying at the start of the Bronze Age. The rapid onset of ubiquitous dairying at a point in time when steppe populations are known to have begun dispersing offers critical insight into a key catalyst of steppe mobility. The identification of horse milk proteins also indicates horse domestication by the Early Bronze Age, which provides support for its role in steppe dispersals. Our results point to a potential epicentre for horse domestication in the Pontic–Caspian steppe by the third millennium bc, and offer strong support for the notion that the novel exploitation of secondary animal products was a key driver of the expansions of Eurasian steppe pastoralists by the Early Bronze Age.

Wilkin, S., Ventresca Miller, A., Fernandes, R. et al. Dairying enabled Early Bronze Age Yamnaya steppe expansions. Nature (2021). https://doi.org/10.1038/s41586-021-03798-4

See also...

On the origin of the Corded Ware people

Domestic horses were introduced into Anatolia and Transcaucasia during the Bronze Age (Guimaraes et al. 2020)

Over at Science Advances at this LINK. This is a very important paper because it basically eliminates West Asia as the source of the modern domestic horse lineage, which leaves the Pontic-Caspian steppe in Eastern Europe as the only viable option.

It also corroborates the linguistic theory that the Proto-Indo-European homeland was located on the Pontic-Caspian steppe. That's because the horse is a key animal in the Proto-Indo-European pantheon, and it appears in Indo-European mythology in intricate roles. This suggests that the speakers of Proto-Indo-European weren't just familiar with the horse but also managed to domesticate it. From the paper:

Abstract: Despite the important roles that horses have played in human history, particularly in the spread of languages and cultures, and correspondingly intensive research on this topic, the origin of domestic horses remains elusive. Several domestication centers have been hypothesized, but most of these have been invalidated through recent paleogenetic studies. Anatolia is a region with an extended history of horse exploitation that has been considered a candidate for the origins of domestic horses but has never been subject to detailed investigation. Our paleogenetic study of pre- and protohistoric horses in Anatolia and the Caucasus, based on a diachronic sample from the early Neolithic to the Iron Age (~8000 to ~1000 BCE) that encompasses the presumed transition from wild to domestic horses (4000 to 3000 BCE), shows the rapid and large-scale introduction of domestic horses at the end of the third millennium BCE. Thus, our results argue strongly against autochthonous independent domestication of horses in Anatolia.

Guimaraes et al., Ancient DNA shows domestic horses were introduced in the southern Caucasus and Anatolia during the Bronze Age, Science Advances 16 Sep 2020: Vol. 6, no. 38, eabb0030, DOI: 10.1126/sciadv.abb0030

See also...

Of horses and men #2

Fascinating stuff courtesy of Fages et al. at the Journal of Archaeological Science: Reports (emphasis is mine):

Abstract: The domestication of the horse and the development of new equestrian technologies have had a far-reaching impact on human history. Disentangling the respective role that horse males and females played during this process is, however, difficult based on iconography and osteological data alone. In this study, we leveraged an extensive ancient DNA time-series to determine the molecular sex of 268 horses spread across Eurasia and charted the male:female sex ratio through the last 40,000 years. We found even sex ratios in the Upper Palaeolithic and up until ~3900 years BP. However, we identified a striking over-representation of horse males in more recent osseous assemblages, which was particularly magnified in funerary contexts but also significant in non-ritual deposits. This suggests that the earliest horse herders managed males and females alike for more than one thousand years after domestication at Botai, but that the human representation and use of horses became gendered at the beginning of the Bronze Age, following the emergence of gender inequalities in human societies.

...

The time period around ~3900 years ago marked a drastic shift in male:female sex ratios inferred from excavated remains, after which the horse osteological record comprises approximately four males for every female (Fig. 2). This over-representation of horse males was maintained when disregarding those animals excavated from ritual burial sites (77/25 ~ 3.08 males for every female) and even more pronounced in the animal bones found in funerary contexts (66/14 ~ 4.71 males for every female). This indicates that the status of male and female horses dramatically changed during the Bronze Age period. This is in line with archaeozoological evidence from the Late Bronze Age cemeteries of the Volga-Ural region associated with the Sintashta, Potapovka and Petrovka cultures, that suggest a domination of male horses in funerary rates (Kosintsev, 2010). Interestingly, this pattern somehow mirrors that observed in humans, for whom a clear binary gender structure ubiquitous across all funerary practices, clothing, personal ornaments and representations is not observed during the Neolithic but became the norm from the transition between the Neolithic and the Bronze Age onwards (Robb and Harris, 2018). In addition, the prevalence of male horses in funerary contexts throughout the past three millennia is in line with archaeological evidence from burial sites (Bertašius and Daugnora, 2001, Taylor, 2017) and suggests that stallions (or geldings) were more prized for sacrificial rituals. This is possibly due to symbolic attributes then-associated with masculinity, mounted warriors and chariotry, such as power, protection and strength (Frie, 2018). In particular, petroglyph images associated with vehicles, characterized by two wheels with spokes, became typical by the late third – early second millennium BCE (Jacobson-Tepfer, 2012). They are generally associated with male warriors and the emergence of mobile warfare (Anthony, 2007) or ritual needs, in particular the passage to the after-life land (Jones-Bley, 2000). This suggests an essential ideological role of stallions and their use in elite warfare and ritual practices (Drews, 2004, Kelekna, 2009, Novozhenov and Rogozhonskiy, 2019).

...

Future research should focus on assessing the molecular sex of horses from Early and Middle Bronze Age Pit Grave and Catacomb cultures, which do show evidence for social inequality, but for which sex inequalities remain to be investigated.

Fages et al., Horse males became over-represented in archaeological assemblages during the Bronze Age, Journal of Archaeological Science: Reports Volume 31, June 2020, 102364, https://doi.org/10.1016/j.jasrep.2020.102364

See also...

Of horses and men

Inferring the linguistic affinity of long dead and non-literate peoples: a multidisciplinary approach

The mystery of the Sintashta people

Latest on Sintashta-Petrovka chariots (Lindner 2020)

Open access at Antiquity at this LINK. As far as I can tell, several individuals from the graves analyzed in this paper are in my ancient DNA dataset and the Global25 datasheets. Sample I1064 from the Kamennyi Ambar 5 cemetery comes to mind. Here's the abstract:

In Eastern Europe, the use of light vehicles with spoked wheels and harnessed horse teams is first evidenced in the early second-millennium BC Sintashta-Petrovka Culture in the South-eastern Ural Mountains. Using Bayesian modelling of radiocarbon dates from the kurgan cemetery of Kamennyj Ambar-5, combined with artefactual and stratigraphic analyses, this article demonstrates that these early European chariots date to no later than the first proto-chariots of the ancient Near East. This result suggests the earlier emergence of chariots on the Eurasian Steppe than previously thought and contributes to wider debates on the geography and chronology of technological innovations.

See also...

The mystery of the Sintashta people

Some myths die hard

Ancient DNA tells us that the Bronze Age wasn't kind to the indigenous populations of Central Asia. It seems to have wiped them out totally. Indeed, Central Asia might well be the only major world region in which native hunter-gatherers failed to make a perceptible impact on the genetics of any extant populations.

Before the Neolithic transition, much of Central Asia was home to hunter-gatherers closely related to those of nearby western Siberia. During the Neolithic, agriculturalists and pastoralists from the Near East gradually moved into the more arable parts of southern and eastern Central Asia, eventually giving rise to the Bactria Margiana Archaeological Complex, or BMAC, and other similar communities.

It's not clear what their relationship was like with the native hunter-gatherers in these areas. But they did mix with them in varying degrees. This is obvious because genome-wide genetic ancestry characteristic of the Botai people, who hunted and eventually domesticated horses on the Kazakh steppe during the 4th millennium BCE, and were probably the archetypal Central Asians for their time, is found at significant levels in a number of later samples from Central Asian farmer and pastoralist sites, such as Dali, Gonur Tepe and Sarazm.

Thus, even though the Neolithic transition did have a big impact on Central Asia, and clearly led to large scale population replacements in some parts of the region, this was just the beginning of these population shifts. Moreover, in some cases the expanding farmer and pastoralist populations seem to have acquired significant indigenous Central Asian ancestry and spread it with them.

The precise geographic extent of the relatively unique Botai-related ancestry in prehistoric Eurasia is still something of a mystery. But to give you a general picture of where it was found from around 6,000 BCE to 2,000 BCE, here's a map with info about samples with significant levels of this type of ancestry from a wide range of sites in space and time.

Going by this map, I'd say it's safe to infer that the Botai-related ancestry was a major feature of practically all forager populations living between the Caspian Sea and the Altai Mountains. It was also present in the Early Bronze Age (EBA) pastoralist population associated with the Steppe Maykop archeological culture of Eastern Europe, so it may have already been in Europe as early as 3,800 BCE, because that's when the Steppe Maykop culture first appeared.

It's an interesting question where the ancestors of the Steppe Maykop herders came from. I once simply assumed that they were closely related to the Maykop people who lived in the Caucasus Mountains. But it's now clear that the populations associated with these two similar cultures were starkly different, with the Maykop people being basically of Near Eastern origin and lacking any discernible Botai-like ancestry. My guess for now is that the Steppe Maykop herders were in large part the descendants of the Kelteminar culture population from just east of the Caspian Sea, but we'll see about that when more ancient DNA comes in.

The other great mystery is what eventually happened to the Steppe Maykop people. Around 3,000 BCE, their culture vanished from the archeological record and their particular genetic signature disappeared from the steppe ancient DNA record. Where did they go? Did they migrate back east?

I don't know, but at about that time other Eastern European steppe herders, those associated with the Yamnaya and Corded Ware archeological cultures, began to stir and migrate in big numbers in basically all directions, including into Steppe Maykop territory. Indeed, unlike the Steppe Maykop population, these groups weren't closely related to any contemporaneous or earlier Central Asians. But they ended up moving into Central Asia, and in a big way too.

Their impact all the way from the Ural Mountains to what are now China and India was profound. For instance, not only did they end up totally replacing the Botai people, but also their horses. For more details on this topic check out the Youtube clip here. I have a strong suspicion that the same sort of thing happened to the aforementioned Steppe Maykop people. In other words, they may have been forced out from the Eastern European steppe, and perhaps sought shelter in the Caucasus Mountains?

Admittedly, I'm not offering anything new here. I just wanted to emphasize a few key points, because I'm still seeing some confusion online about the population history of Central Asia, and especially how it relates to the population history of Europe, and also the Proto-Indo-European homeland question. Make no mistake, thanks to the ancient DNA already available from Central Asia, we can confidently infer the following:

- the chance that the ancient European populations associated with the Yamnaya, Corded Ware and other closely related archeological cultures formed as a result of migrations from Central Asia is zero

- the chance that the Proto-Indo-European homeland was located in Central Asia is zero

- the chance that present-day Europeans, by and large, derive from any ancient Central Asian populations is zero

See also...

Central Asia as the PIE urheimat? Forget it

The Steppe Maykop enigma

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

Early chariot riders of Transcaucasia came from...

I'm finding it increasingly difficult nowadays to fully appreciate all of the ancient DNA samples that are accumulating in my dataset. But it's not entirely my fault.

Among the hundreds of ancient samples published last year there was a couple of Middle Bronze Age (MBA) individuals from what is now Armenia labeled "Lchashen Metsamor" (see here). I wasn't planning to do much with these samples because, even after reading the Nature paper that they came with a couple times over, I didn't have a clue what they were about. But after some digging around, I now know that their people, those associated with the Lchashen Metsamor archeological culture, were among the earliest in Transcaucasia, and indeed the Near East, to use the revolutionary spoked-wheel horse chariot. How awesome is that?

The invention of the spoked-wheel chariot is generally credited to the Middle Bronze Age Sintashta culture of the Trans-Ural steppe in Central Asia, and its rapid spread is often associated with the early expansions of Indo-European languages deep into Asia. On the other hand, some have argued that this type of chariot was first developed in the Near East, and directly derived from solid-wheeled wagons pulled by donkeys.

It's now obvious, thanks to ancient DNA, that the Sintashta people were by and large migrants to Central Asia from somewhere in Eastern Europe, and that they didn't harbor any recent ancestry from the Near East. So if chariot technology spread into the steppes from the Near East, then it did so without any accompanying gene flow, which is possible but not entirely convincing. This begs the question of whether the Lchashen Metsamor population was of Sintashta-related origin, because if it was, then this would corroborate the consensus that spoked-wheel chariots were introduced into Transcaucasia from the steppes to the north.

Below is a Principal Component Analysis (PCA) of West Eurasian genetic variation. It does suggest that the Lchashen Metsamor pair (labeled Armenia_MBA_Lchashen), as well as most of the other currently available samples from what is now Armenia dating to the Middle to Late Bronze Age (MLBA), harbor some steppe ancestry. That's because they appear to form a cline between samples associated with the Sintashta and Kura-Araxes cultures. Of course, the Kura-Araxes culture was a major Early Bronze Age (EBA) archeological phenomenon centered on Transcaucasia and surrounds, so its population can be reasonably assumed to have formed the genetic base of most subsequent populations in the region. The relevant PCA datasheet is available here.

To investigate the possibility of Sintashta-related admixture in Lchashen Metsamor with formal methods, I ran a series of mixture models with the qpAdm software. Here are the three statistically most sound outcomes that I was able to come up with for Lchashen Metsamor:

Armenia_MBA_Lchashen
CWC_Kuyavia 0.183±0.036
Kura-Araxes_Kaps 0.817±0.036
chisq 13.941
tail prob 0.378021
Full output

Armenia_MBA_Lchashen
Balkans_BA_I2163 0.193±0.045
Kura-Araxes_Kaps 0.807±0.045
chisq 14.780
tail prob 0.321267
Full output

Armenia_MBA_Lchashen
Kura-Araxes_Kaps 0.788±0.043
Sintashta_MLBA 0.212±0.043
chisq 14.871
tail prob 0.315451
Full output

I sorted the output by "tail prob", but the fact that Sintashta_MLBA is in third place isn't a problem because the stats in all of these models are basically identical. Indeed, CWC_Kuyavia (Corded Ware culture samples from present-day Kuyavia, North-Central Poland) and Balkans_BA_I2163 (a Bronze Age singleton from what is now Bulgaria) are both very similar and probably closely related to each other and to the Sintashta samples.

Interestingly, and, I'd say, importantly, ancients from the steppe that are closest to Lchashen Metsamor in both space and time, but not particularly closely related to the Sintashta people, don't work too well as a mixture source in such models.

Armenia_MBA_Lchashen
Kubano-Tersk 0.184±0.046
Kura-Araxes_Kaps 0.816±0.046
chisq 22.179
tail prob 0.0526526
Full output

A couple of months ago I suggested that populations associated with the Early to Middle Bronze Age (EMBA) Catacomb culture were the vector for the spread of steppe ancestry into what is now Armenia during the MLBA (see here). After taking a closer look at the Lchashen Metsamor samples, I now think that the peoples of the Sintashta and related cultures were also important in this process. If so, they may have moved from the steppe into Transcaucasia both from the west via the Balkans and the east via Central Asia, and brought with them spoked-wheel chariots. I don't have a clue what language they spoke, but I'm guessing that it may have been something Indo-European.

See also...

The mystery of the Sintashta people

A potentially violent end to the Kura-Araxes Culture (Alizadeh et al. 2018)

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but...

The mystery of the Sintashta people

During the Middle to Late Bronze Age, the steppes southeast of the Ural Mountains, in what is now Russia, were home to communities of metallurgists who buried their warriors with horses and the earliest examples of the spoked-wheel battle chariot.

We don't know what they called themselves, because they didn't leave any written texts, but their archaeological culture is commonly known as Sintashta. It was named after a river near one of their main settlements; an elaborate fortified town that has also been described as an ancient metallurgical industrial center. Another of their well known settlements, very similar to Sintashta, is Arkaim, pictured below courtesy of Wikipedia.

Sintashta is arguably one of the coolest ancient cultures ever discovered by archaeologists. It's also generally accepted to be the Proto-Indo-Iranian culture, and thus linguistically ancestral to a myriad of present-day peoples of Asia, including Indo-Aryans and Persians. No wonder then, that its origin, and that of its population, have been hotly debated issues.

The leading hypothesis based on archaeological data is that Sintashta is largely derived from the more westerly and warlike Abashevo culture, which occupied much of the forest steppe north of the Black and Caspian Seas. In turn, Abashevo is usually described as an eastern offshoot of the Late Neolithic Corded Ware Culture (CWC), which is generally seen as the first Indo-European archaeological culture in Northern Europe (see here).

Below is a Principal Component Analysis (PCA) featuring 38 Sintashta individuals from the recent Narasimhan et al. 2018 preprint. Note that the main Sintashta cluster overlaps almost perfectly with the main CWC cluster. The relevant datasheet is available here.

Moreover, many ancient and present-day South and Central Asians, particularly those identified with or speaking Indo-Iranian languages, appear to be strongly attracted to the main Sintashta cluster, forming an almost perfect cline between this cluster and the likely Indus Valley diaspora individuals who show no evidence of steppe ancestry.

This is in line with mixture models based on formal statistics showing significant Sintashta-related ancestry in Indo-Iranian-speakers (for instance, see here), and high frequencies of Y-haplogroup R1a-Z93 in both the Sintashta and many Indo-Iranian-speaking populations.

Some of the Sintashta samples are outliers from the main Sintashta cluster, and that's because they harbor elevated levels of ancestry related to the Mesolithic and Neolithic foragers of Eastern Europe and/or Western Siberia. This is especially true of a pair of individuals who belong to Y-haplogroup Q. However, this doesn't contradict archaeological data, which suggest that the Sintashta community may have been multi-cultural and multi-lingual. Indeed, it's generally accepted based on historical linguistics data that there were fairly intense contacts in North Eurasia between the speakers of Proto-Indo-Iranian, Proto-Uralic and Yeniseian languages.

Thus, it appears that there's not much left to debate because ancient DNA has seemingly backed up the most widely accepted hypotheses about the origin of Sintashta and its people, and their identification mainly as Proto-Indo-Iranian-speakers.

However, a sample from a Sredny Stog II culture burial on the North Pontic steppe, in what is now eastern Ukraine, has complicated matters somewhat. This individual, known as Ukraine_Eneolithic I6561, not only clusters very strongly with the most typical Sintashta samples, but also belongs to Y-haplogroup R1a-Z93. On the other hand, none of the CWC remains sequenced to date belong to this particular subclade of R1a (although, obviously, they do belong to a host of near and far related R1a subclades).

I've never seen anyone worth reading propose that Sintashta might derive from Sredny Stog II instead of Abashevo. And no wonder, because Sredny Stog II was long gone when Sintashta appeared in the archaeological record.

But if CWC remains continue to fail to produce R1a-Z93, while, at the same time, the steppes of eastern Ukraine and surrounds are shown to be a hotbed of R1a-Z93 from the Sredny Stog to the Sintashta periods, which I think is possible, then ancient DNA might well force a serious re-examination of how the awesome Sintashta culture and people came to be.

See also...