User:Tewdar/sandbox/WSH V6

In archaeogenetics, Western Steppe Herder (WSH), is the name given to a distinct ancestral component first identified in individuals from the Pontic-Caspian steppe during the Eneolithic and thought to have formed at least by around the turn of the 5th millennium BC. This ancestry is found in substantial levels in many ancient and modern populations. It is also referred to as Yamnaya Ancestry, Yamnaya-Related Ancestry, Steppe Ancestry or Steppe-Related Ancestry, and may also be divided chronologically into Eneolithic, Early to Middle Bronze Age, and Middle to Late Bronze Age steppe ancestry, each with distinctive characteristics.



So-called 'Eneolithic steppe' ancestry is usually modelled as an mixture of eastern European hunter-gatherer (EHG) and Caucasus Hunter-Gatherer (CHG) ancestry in roughly equal proportions, with the majority of the Y-DNA haplogroup contribution from EHG males. So called steppe Early to Middle Bronze Age (steppe EMBA) ancestry consists of an additional Anatolian Farmer component and a small amount of WHG. So called steppe Middle to Late Bronze Age (steppe MLBA) ancestry additionally contains a substantial contribution from Neolithic European farmers.

Around 3,000 BC, populations bearing steppe ancestry embarked on a massive expansion throughout Eurasia, which is considered to be associated with the dispersal of many of the Indo-European languages by most contemporary linguists, archaeologists, and geneticists. These migrations are linked to the origins of the Afanasievo culture in South Siberia, who are genetically indistinguishable from Yamnaya Samara, the Corded Ware culture of North-Central and Eastern Europe, whose members were of about 75% steppe ancestry, and the Bell Beaker culture, who were around 50% steppe ancestry. The expansion of people with this ancestry resulted in the virtual disappearance of Early European Farmer (EEF) male haplotypes from the European gene pool, and significantly altered the cultural and genetic landscape of Europe.

During the Bronze Age, eastern Corded Ware people, with admixture from Central European cultures, remigrated onto the steppe, forming the Sintashta culture south of the Ural mountains. Through the Andronovo culture and Srubnaya culture, Steppe Middle to Late Bronze Age ancestry was carried into Central Asia and South Asia along with Indo-Iranian languages, leaving a long-lasting cultural and genetic legacy.

In modern Europeans, WSH ancestry peaks among Norwegians (c. 50%), while in South Asia, it peaks among the Kalash people at around c. 30–50%.

Steppe ancestry is associated with speakers of Indo-European languages by several modern geneticists, archaeologists, and linguists. Cultures with significant levels of Steppe ancestry, such as the Afanasievo, Corded Ware, Bell Beaker, and Andronovo cultures, have been seen as likely vectors for the spread of Indo-European languages into Europe and Asia.

Identification
A 2014 study by Lazaridis et al. found that most contemporary Europeans derive from at least three "highly differentiated" populations: west European hunter-gatherers (WHG), a clade that includes Loschbour man, an 8000-year old hunter-gatherer from Luxembourg, Early European Farmers (EEF), mainly of Near Eastern origin with some west European hunter-gatherer related ancestry, a clade including a 7000-year old individual from Stuttgart associated with the Linearbandkeramik culture, and Ancient North Eurasians (ANE), a population related to Upper Palaeolithic Siberians, defined by the remains of a c. 24,000-year old boy from the Mal'ta–Buret' culture. The article questions when and how Europeans acquired ANE ancestry, and speculates that this may have happened c. 4500 years ago, during the late Neolithic, based on the appearance of novel mtDNA haplogroups and archaeological discontinuity around this time.

In 2015, a study by Haak et al. found that, at the beginning of the Neolithic, Russia had been inhabited by a "distinctive population" of individuals with "high affinity" to Ancient North Eurasian ancestry. This population clusters at one end of a hunter gatherer cline across Europe, which they name eastern European Hunter Gatherers (EHG). The study reports that the steppe herders of the Yamnaya culture of c. 6000–5000 years ago were descended from a mixture of the eastern European hunter-gatherers and another unidentified population of Near Eastern ancestry.

A study by Jones et al. 2015 notes that the previous study by Lazaridis et al. allowed inference of an ANE component in European ancestry, subsequently shown by Haak et al. to have spread into Europe through an incursion of Steppe herders carring partial ancestry from Ancient North Eurasians, as well as a second, undetermined source beginning around 4,500 years ago. The article describes a Late Upper Palaeolithic genome from Satsurblia Cave and a Mesolithic genome from Kotias Klde cave in Georgia, who belong to a previously unknown ancient clade which the authors name Caucasus hunter-gatherer (CHG). The authors state that this clade represents the previously undetermined source of 'Near Eastern' ancestry in the Yamnaya.

Definition
Early 'Steppe ancestry', from the Eneolithic to the Early Bronze Age, is usually described as an admixture of two diverse populations, in approximately equal proportions; first, a population that is related to both modern populations and Mesolithic hunter-gatherers from the Caucasus mountains, as well as populations from Neolithic and Copper Age Iran; and second, a population of Mesolithic Eastern European hunter-gatherers that is modelled as an admixture of Western European hunter-gatherers and Ancient North Eurasians. The Eastern European hunter-gatherer component was first defined by Haak et al. 2015, based on two genetically similar Mesolithic or Neolithic individuals from Samara and Lake Onega in Russia. Haak et al. 2015, model the Eastern European hunter-gatherer component as 40% ANE and 60% WHG, whereas Lazaridis et al. model it as 75% ANE. This ancestry, without additional admixture from other populations, is sometimes named 'Eneolithic steppe' ancestry or 'pre-Yamnaya' ancestry. Wang et al. 2019 observe that this ancestry profile is found in several Eneolithic individuals from Samara and the steppe directly north of the Caucasus.

Jeong et al. distinguish between the earlier populations of the Yamnaya and Afanasievo cultures, which they note is often named 'steppe Early and Middle Bronze Age', and later populations associated with diverse cultures including Potapovka, Sintashta, Srubnaya and Andronovo, which they note is often called 'steppe Middle and Late Bronze Age', which they describe as "largely descended from the preceding steppe Early and Middle Bronze Age gene pool, with a substantial contribution from Late Neolithic Europeans". Collectively, they refer to these two populations as Western Steppe herders (WSHs).

Origins and expansion


The location of the initial formation of so-called 'steppe ancestry', from admixture of EHG and CHG populations, is uncertain. It is found first in Eneolithic cultures in the Pontic Caspian steppe, such as Khvalynsk and the north Caucasus. Wherever it originated, 'steppe ancestry' is thought to have rapidly spread, first across the Pontic-Caspian steppe, and then to Siberia, Central and Western Europe, and South Asia. By around 3,000 BC, 'steppe ancestry' had expanded over a region of more than 2,000 miles of the Eurasian steppe, found in individuals from the Yamnaya culture in Eastern Europe and the Afanasievo culture in the Altai mountains.

Allentoft et al. states that individuals from the Corded Ware, Bell Beakers, Unetice, and the Scandinavian cultures are "genetically very similar to each other", exhibiting a "cline of genetic affinity with Yamnaya, with highest levels in Corded Ware, lowest in Hungary, and central European Bell Beakers being intermediate."

In Haak et al 2015, a hunter-gatherer from Samara, I0124, c. 5650-5555 BC was found to be ancestral for both haplogroup R1b1a1 (M478) and R1b1a2 (M269). The authors suggest that this individual could be designated as R1b1* (xR1b1a1, xR1b1a2). This individual was therefore "basal to most west Eurasian R1b individuals which belong to the R-M269 lineage as well as to the related R-M73/M478 lineage that has a predominantly non-European distribution".

Eneolithic steppe
Mathieson et al. 2015 states that admixture between populations of Near Eastern ancestry and the EHG had begun by 5200–4000 BC, predating Yamnaya by at least 1,000 years, with 3 individuals at the Eneolithic Khvalynsk II cemetery described as a heterogeneous population, with some individuals genetically resembling EHGs and some closer to Yamnaya. These individuals, taken together, are estimated to be around three-quarters EHG and one-quarter "Armenian-related ancestry". The three individuals belong to Y-chromosome haplogroups R1a (mtdna U5a1), which the authors note is not found in later elite Yamnaya graves, R1b(mt H2a1), and Q1a(mt U4a2 or U4d), the first two of which are found in preceding EHG populations. The paper states that these results "suggest a great degree of continuity with the EHG for the Eneolithic population." The high-status R1b1 individual, a haplogroup which they note is found in "other high-status individuals buried under kurgans in later Yamnaya graves in this region, so he could be regarded as a founder of an elite group of patrilineally related families", is buried with 293 copper artifacts, which amounts to 80% of all copper artefacts found at the Khvalynsk cemetery.

A 2019 study by Wang et al. notes that the steppe ancestry proﬁle is already visible in the Eneolithic period c. 4200BCE. They report that three individuals from the archaeological site Progress 2 (two males, Ydna R1b1 x 2, mtdna I3a and H2) and Vonyuchka 1 (female, mtdna T2a1b) in the North Caucasus Eneolithic steppe harbour EHG and CHG related ancestry, and are genetically very similar to Eneolithic individuals from Khvalynsk II and the Samara region. The North Caucasus samples have higher levels of CHG than those of Khvalynsk, overlapping the later Yamnaya individuals.

Archaeologist David Anthony speculates that the Khvalynsk-Progress-2 mating network, located between the middle Volga and the North Caucasus foothills, makes a "plausible genetic ancestor for Yamnaya".

At Khvalynsk, the most common Y-DNA haplogroup is R1b, with some Q1a, and some other minority haplogroups, including R1a and J1.

In Mathieson 2018, an individual from a Sredny Stog cemetery at Oleksandriia in eastern Ukraine c. 4045-3974 calBCE (Y R1a1a1, mt H2a1a) has around combined 70–80% total CHG/EHG ancestry with an additional c. 20% Neolithic farmer ancestry. This individual is the earliest known example with the genetic adaption of lactase persistence.

Yamnaya c. 3300–2600BC


When the first Yamnaya whole genomes were published in 2015, it was stated that the Yamnaya individuals had no Anatolian Farmer ancestry,{{Haak, Allentoft, Mathieson 2015) but now, following larger studies it is now generally agreed that Yamnaya had some Anatolian farmer ancestry.{{sfn|Anthony|2019a}} Mathieson et al. 2018 reports two Yamnaya individuals from further west than previous samples with high levels of steppe-related ancestry. One individual from Ozera in Ukraine and one from Bulgaria, both dated to c. 3000 BC, have northwestern Anatolian Neolithic-related admixture, which they state is "the first evidence of such ancestry in Yamnaya-associated individuals."{{sfn|Mathieson et al.|2018}} Wang et al. 2019 notes that later Yamnaya culture individuals from Samara ('Yamnaya Samara') and Ukraine or the Caucausus have additional admixture from Anatolian farmers. Yamnaya Samara are stated to have 13.2% AF ancestry, while those from Yamnaya Ukraine and the Caucasus around 16.6%, a difference that the authors describe as statistically insignificant.{{sfn|Wang et al.|2019}} Wang et al. 2019 speculate that, in the North Caucasus, the AF genetic contribution "could have occurred through immediate contact of Yamnaya populations with groups from the Caucasus or further south. Alternatively, in order to explain the additional increase in WHG-related ancestry, the authors suggest that contact with cultures west of Yamnaya, such as Globular Amphora and Cucuteni–Trypillia may have been another possible source of this ancestry.{{sfn|Wang et al.|2019}}

Wang et al. concluded that the Anatolian Farmer admixture in Yamnaya came specifically from European farmers, and not from the Caucasus. They note that a population with a mixture of 80% Anatolian Farmer and 20% WHG, such as samples from the Tripol'ye or Globular Amphorae cultures, could account for the combined 10–18% of Anatolian Farmer and Western European hunter-gatherer ancestry in Yamnaya. Although these additional components in Yamnaya could have come from the Tripol'ye or Globular Amphorae cultures, it is quite possible that they could have come from another source.{{sfn|Anthony|2019a}}

Mathieson et al. 2015 states that the early Yamnaya individuals from Samara and Kalmykia, the Afanasievo culture, and the Poltavka Middle Bronze Age (2900–2200 BC) population that followed the Yamnaya in Samara comprise a "genetically homogeneous" cluster, carrying predominantly R1b Y-DNA haplogroups with a minority of I2a.{{sfn|Mathieson et al.|2015}} Most Yamnaya males carry R1b-Z2103.{{sfn|Papac et al.|2021}}

Haak et al. 2015 found that Bronze Age Yamnaya mtDNA haplogroups (n=36) included H(25%),U5a(16.7%), T2(11.1%), W(8.3), K(8.3), J(5.6%), and a variety of others (N1a 2.8,I 2.8, X 2.8, U of various subgroups...)

Haak2015 state that the "uniformity of R1b Y-chromosomes in this sample suggests a patrilineal organization of the Yamnaya, or at least of the people who were given expensive Kurgan burials." The authors state that they "cannot exclude the presence of other haplogroups in the general population, or in other individuals located elsewhere in the expansive Yamnaya horizon.", and also "emphasize the absence of M412 (the dominant lineage within haplogroup R-M269 in Europe) in this sample", and "the absence of the R1a haplogroup which was detected in the Corded Ware and Late Bronze Age Halberstadt individual from central Europe."{{sfn|Haak et al.|2015}}

Afanasievo Culture c. 3300 to 2500 BC


Allentoft et al. found that individuals from the early Bronze Age Afanasievo Culture are "genetically indistinguishable" from Yamnaya, confirming an early expansion across the steppe to the east.

Wang et al. 2021 note that the individuals from the Afanasievo culture c. 3100 BC are genetically "extremely similar" to Yamnaya steppe pastoralists. They report two individuals from the Chemurchek culture with "Yamnaya–Afanasievo ancestry" of c. 33–51%. They state that, from the Middle Bronze Age, there is "no compelling evidence" for the persistence of the Yamnaya-derived lineages that spread with the Afanasievo culture in Mongolia. Instead, they state that the Yamnaya-related ancestry of this period "can only be modelled as deriving from a later spread related to people of the Sintashta and Andronovo horizons of the Middle to Late Bronze Age who were themselves a mixture of around two-thirds Yamnaya-related and one-third European farmer-related ancestry." They state that this "Sintashta-related" (or steppe_MLBA) ancestry at levels of c. 0-57% is found in substantial proportions only in western Mongolia.

Most Afanasievo males belong to haplogroup R1b, with some Q1a.(Narasimhan et al. 2019)

Corded Ware c. 2900–2350 BC


Archaeogenetics reveals a major and relatively sudden population turnover in Europe during the early third millennium BC.

Corded Ware individuals have been shown to be genetically distinct from previous European Neolithic cultures of North-Central and Northeastern Europe, with around 75% of their ancestry similar to Yamnaya individuals from the Pontic-Caspian steppe.

This 'steppe' ancestry then spread rapidly throughout Europe during the third millenium BC to Britain, Ireland, Iberia, and the Mediterranean.

Papac et al. find that early Corded ware individuals were "genetically exceptionally diverse", with some individuals close to GAC and others close to Yamnaya. The study detects a "Latvia_MN-like ancestry" genetic contribution to early Corded Ware, which, combined with "the absence of Y-chromosomal sharing between early CW and Yamnaya males" suggests a "limited or indirect role of known Yamnaya in the origin and spread of CW to central Europe." Instead, the authors suggest that Corded Ware genetic profile originates either from a northeast European Eneolithic forest-steppe admixture with a Yamnaya-like population, or alternatively a "hitherto unsampled steppe population who carried excess Latvia_MN-like ancestry", which the authors consider to be a less likely scenario.

Papac et al. argue that "the assimilation process of individuals without steppe ancestry into early CW society was female-biased", but also find females with high levels of steppe ancestry, suggesting that they also participated in the CW migration, or else were "assimilated from nearby Yamnaya groups", such as Yamnaya Hungary.

Subgroups

 * Baltic

The genetic prehistory of the Baltic Sea region - Mittnik


 * Battle Axe

The genomic ancestry of the Scandinavian Battle Axe Culture people and their relation to the broader Corded Ware horizon - Malmström


 * Fatyanovo Culture

Genetic ancestry changes in Stone to Bronze Age transition in the East European plain (Saag)


 * Switzerland

Ancient genomes reveal social and genetic structure of Late Neolithic Switzerland - Furtwängler

Bell beaker c. 2500–1800 BC)


High proportions (~50%) of 'steppe' related ancestry are found in Bell Beaker individuals from Germany, the Czech Republic, and Britain. The ancestry of Bell beaker individuals outside of Iberia derives from a mixture of steppe populations and preceding European Neolithic farmers. In Britain, 90% of the gene pool was replaced within a few hundred years.

The earliest Bell beaker individuals are genetically similar to Corded Ware, indicating genetic continuity to some extent.

Beaker males with steppe ancestry are predominantly YDNA R1b-M269. Olalde et al. found that, outside Iberia, this haplogroup was present in 84 out of 90 males. Of the 60 haplogroup R1b-M269 males, all but 2 had the R1b-P312 polymorphism, which remains the prevalent haplogroup in western Europe today.

Papac et al. found that late Bell Beaker individuals from Bohemia from 2400 BC onwards carry c. 20% Middle Eneolithic–like ancestry compared to Bell Beaker individuals before this time, and found some support that this additional ancestry came from a local source.

The authors observe a "closer phylogenetic relationship between the Y chromosome lineages found in early CW and BB than in either late CW or Yamnaya and BB." R1b-L151 is the most common (55%) Y-lineage among early CW males, and the study reports one branch ancestral to R1b-P312, which is "the dominant Y-lineage in BB." The authors suggest that R1b-P312 may have originated "somewhere between Bohemia and England, possibly in the vicinity of the Rhine, followed by an expansion northwest and east."

Srubnaya c. 1850-1450 BC


The Late Bronze Age Srubnaya culture that follows the Poltavka period has additional (~17%) Anatolian Neolithic or Early European Farmer ancestry that was absent from the previous population.

Iron Age nomads (Cimmerians, Scythians, and Sarmatians)
Ancient genomes suggest the eastern Pontic-Caspian steppe as the source of western Iron Age nomads - Krzewińska

Sintashta c. 2050–1900 BC, Andronovo c. 2000–1450 BC
Damgaard et al 2018 note that both Early Bronze Age (c. 3000–2500 BC) Yamnaya and Afanasievo populations, and the people of the Late Bronze Age (c. 2300–1200 BC) Sintashta and Andronovo cultures "carry substantial amounts of EHG and CHG ancestry" with Sintashta carrying an additional genetic component "acquired through admixture with European Neolithic farmers during the formation of the Corded Ware complex, reflecting a secondary push from Europe to the east through the forest-steppe zone."

The most common haplogroup among Sintashta culture males is R1a, with some R1b and a minority of Q1a and I2a.(Narasimhan et al. 2019)

Iberia
Olalde et al. 2019 report that, by c. 2000 BC, around 40% of Iberia's ancestry and nearly all of its Y-DNA haplogroups had been replaced by people with Steppe ancestry.

Western Mediterranean islands
Fernandes et al. 2020 report an individual from the Balearic Islands c. 2400 BC with steppe ancestry, probably from Iberia, and in Sicily by c. 2200BC, partly from Iberia.

Sardinia
Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia - Marcus

Southeastern Europe
Mathieson et al. 2018 report two individuals (one from the Varna I cemetery c. 4711–4550 BC and another from Smyadovo c. 4550–4450 BC) with steppe-related ancestry. The authors state that the occurrence of this ancestry must have been sporadic between c. 5000–4000 BC as other individuals from the Balkans have no evidence for such ancestry. Between c. 3400–1100BC Bronze Age Balkans populations are found to have around 30% steppe-related ancestry on average, with the highest proportions appearing after c. 1700BC, and lower proportions before 2500BC.

Mycenaean Greece
Lazaridis et al. 2017 found that, in one possible scenario, Mycenaeans can be modelled as "a mixture of Minoans and Bronze Age steppe populations", suggesting a model where 'eastern' ancestry arrived in both Crete and mainland Greece, followed by "about 13–18% admixture with a 'northern' steppe population in mainland Greece only."

Central/South Asia
Damgaard et al 2018 finds that steppe ancestry was more likely to have arrived in South Asia in the Late Bronze Age (c. 2300–1200 BC) rather than the Early Bronze Age (c. 3000–2500 BC), which the authors consider to be "more consistent with archaeological and linguistic chronology." The authors thus suggest that the Yamnaya and Afanasievo related migrations "did not have a direct genetic impact in South Asia."

Narasimhan et al. 2019 report the arrival of "Steppe pastoralist–derived ancestry" in Turan by 2100 BC. They report outliers from BMAC sites carrying ancestry "ultimately derived from Western_Steppe_EMBA pastoralists, in the distinctive admixed form typically carried by many Middle to Late Bronze Age Steppe groups (with roughly two-thirds of the ancestry being of Western_Steppe_EMBA origin, and the rest con-sistent with deriving from European farmers)." They state that their data documents "a southward movement of ancestry ultimately descended from Yamnaya Steppe pastoralists who spread into Central Asia by the turn of the second millennium BCE."

Italy
Antonio et al. 2019 report a "major ancestry shift" at some point between 2900 and 900 BCE. Individuals after 900BCE show a "clear ancestry shift" from the previous Copper Age. The genetic shift is modelled by an overall introduction of c. 30 to 40% ancestry from Bronze and Iron Age populations from the Pontic-Caspian Steppe. The authors report that, by 900 BCE at the latest, the genetics of the inhabitants of central Italy had begun to approximate the genetics of modern Mediterranean populations.

A later study by Saupe et al. 2021 confirmed that steppe ancestry had arrived in Northern Italy at least by c. 2000 BCE and in Central Italy by c. 400 years later, which they suggest may have arrived through Late Neolithic or Bell Beaker groups from Central Europe.

Sex bias
Extensive Farming in Estonia Started through a Sex-Biased Migration from the Steppe - Saag

Ancient X chromosomes reveal contrasting sex bias in Neolithic and Bronze Age Eurasian migrations - Goldberg

Failure to replicate a genetic signal for sex bias in the steppe migration into central Europe - Lazaridis,Reich

Modern populations
Steppe ancestry is ubiquitous in many modern populations. In Europe it is now found in higher levels in north central Europe, and at lower levels in southern Europe.

Haak et al. found that, among the modern populations they studied, Norwegians had the highest levels of steppe ancestry, c. 50%.

Lazaridis et al. 2016 report a substantial demographic impact of steppe-related populations on South Asia. The south Indian Mala population are inferred to have c. 18% steppe-related ancestry. The Kalash of Pakistan are inferred to have c. 50% steppe ancestry, a similar proportion to contemporary northern Europeans. A later study by Narasimhan et al. (2019) gave around c. 30% steppe ancestry for the Kalash people.

Phenotypes
Genetic contributions to variation in human stature in prehistoric Europe - Cox

Human evolution: a tale from ancient genomes - Llamas

Relationship to IE languages


Haak et al 2015 supplement note that, before the development of writing systems and modern means of travel and communication, "languages must have spread through direct contact and, at least to some extent, with migrants, and thus the study of ancient DNA, which can trace the migration of people, is relevant to evaluating models of language dispersal."

The Pontic-Caspian steppe is often suggested as the possible Urheimat of the Indo-European languages, and the WSH cluster is often associated with the original speakers of Proto-Indo-European in this hypothesis. The Yamnaya and Corded Ware cultures have been seen as possible vectors for the spread of Indo-European languages into Europe.

David Anthony states that the Indo-European languages that he argues were probably spoken by the Western Steppe Herders were initially the result of "a dominant language spoken by EHGs that absorbed Caucasus-like elements in phonology, morphology, and lexicon."

Haak et al. states that, while their data cannot determine the location of the Proto-Indo-European homeland, their results "make a compelling case for the steppe as a source of at least some of the Indo-European languages in Europe by documenting a massive migration c. 4,500 years ago associated with the Yamnaya and Corded Ware cultures."

Haak et al provide a summary of 2 mainstream, and two more marginal, theories of PIE homeland. They argue that both the Anatolian and Balkan hypotheses for origin of IE languages have become less plausible as result of their study. They argue that the discovery of a migration from the steppe into central Europe during the Late Neolithic makes the 'Steppe hypothesis' more plausible. The study also rejects a later breakup of PIE, as a migration into Europe had already occurred by c. 2500BC, and suggests that an 'elite dominance' model of introduction of IE languages is unnecessary given the large number of people involved in the migration.

They also argue that the Armenian plateau hypothesis becomes more plausible due to evidence of admixture in Yamnaya from "a population of Near Eastern ancestry" similar to modern Armenians. The authors note that "the question of what languages were spoken by the 'Eastern European hunter-gatherers' and the southern, Armenian-like, ancestral population remains open."

An analysis by Allentoft et al. describes the migrations during the Early Bronze Age as "a probable scenario for the spread of Indo-European languages, in line with reconstructions based on some archaeological and historical linguistic data."

Narasimhan et al., noting that "the Steppe ancestry in South Asia has the same profile as that in Bronze Age Eastern Europe", argue that migration of people between these regions "likely spread the unique features shared between Indo-Iranian and Balto-Slavic languages." (Satem, Ruki...)

Wang et al. 2021 state that their genetic data results "add weight to the theory that the Tocharian languages of the Tarim Basin spread through the migration of Yamnaya descendants to the Altai Mountains and Mongolia (in the guise of the Afanasievo culture) from whence they spread further to Xinjiang" and "increase the evidence in favour of the hypothesis that the split of the second-oldest branch in the Indo-European language tree occurred at the end of the fourth millennium BC."

Zhang et al. 2021 state that, "although Tocharian may have been plausibly introduced to the Dzungarian Basin by Afanasievo migrants during the Early Bronze Age, we find that the earliest Tarim Basin cultures appear to have arisen from a genetically isolated local population that adopted neighbouring pastoralist and agriculturalist practices."

Olalde et al. note that, in Iberia, the influx of steppe ancestry did not always result in the introduction of Indo-European languages, as in the case of Basques, who speak a non-Indo-European language but still have substantial levels of Steppe ancestry.

Alternatively, according to Mathieson 2018, the genetic data may plausibly support a PIE homeland in the Caucasus or Iran, with an initial westward population movement associated with Anatolian language speakers, followed by a migration north and mixture with EHG groups to form a population of Late Proto-Indo European speakers. The authors note that "it remains possible that Indo-European languages were spread through southeastern Europe into Anatolia without large-scale population movement or admixture", a scenario that would not require a PIE homeland south of the Caucasus mountains.

In the linguistic supplement to Damgaard et al 2018, the authors link the Early Bronze Age intrusion of the Indo-Iranian languages in Central and South Asia to migrations of groups associated with the Andronovo culture, on the basis that they carried LBA Steppe ancestry, similar to that of individuals associated with the Corded Ware culture in Europe. The authors also note the "lack of genetic indications for an intrusion into Anatolia" which "refutes the classical notion of a Yamnaya-derived mass invasion or conquest", instead supporting a scenario where "the speakers of the Anatolian languages established themselves in Anatolia by gradual infiltration and cultural assimilation."