Proto-Indo-European homeland

The Proto-Indo-European homeland (or Indo-European homeland) was the prehistoric "Urheimat" of the Indo-European languages – the region where the proposed common ancestor of those languages, the Proto-Indo-European language (PIE), was originally spoken. From this region, its speakers migrated east and west, and went on to form the proto-communities of the different branches of the language family.
The most widely accepted proposal about the location of the Proto-Indo-European homeland is the steppe hypothesis, which puts the archaic, early and late PIE homeland in the Pontic–Caspian steppe around 4000 BC. The leading competitor is the Anatolian hypothesis, which puts it in Anatolia around 8000 BC. A notable third possibility, which has gained renewed attraction due to recent aDNA research, is the Armenian hypothesis which situates the homeland for archaic PIE south of the Caucasus. Several other explanations have been proposed, including the outdated but historically prominent North European hypothesis, the Neolithic creolisation hypothesis, the Paleolithic Continuity Theory, the Arctic theory, and the "Indigenous Aryans" (or "Out of India") hypothesis. These are not widely accepted, or are considered to be fringe theories.
The search for the homeland of the Indo-Europeans began in the late 18th century with the rediscovery of the Indo-European language family. The methods used to establish the homeland have been drawn from the disciplines of historical linguistics, archaeology, physical anthropology and, more recently, human population genetics.
Hypotheses.
Main theories.
The steppe model, the Anatolian model, and the Near Eastern (or Armenian) model, are the three leading solutions for the Indo-European homeland. The steppe model, placing the Proto-Indo-European (PIE) homeland in the Pontic-Caspian steppe around 4000 BC, is the theory supported by most scholars.
According to linguist Allan R. Bomhard (2019), the steppe hypothesis proposed by archeologists Marija Gimbutas and David W. Anthony "is supported not only by linguistic evidence, but also by a growing body of archeological and genetic evidence. The Indo-Europeans have been identified with several cultural complexes existing in that area between 4,500—3,500 BCE. The literature supporting such a homeland is both extensive and persuasive [...]. Consequently, other scenarios regarding the possible Indo-European homeland, such as Anatolia, have now been mostly abandoned," although critical issues such as the way the proto-Greek, proto-Armenian, proto-Albanian and proto-Anatolian languages became spoken in their attested homeland are still debated inside the steppe model.
The Anatolian hypothesis proposed by archeologist Colin Renfrew places the pre-PIE homeland in Anatolia around 8000 BC, and the homeland of Proto-Indo-European proper in the Balkans around 5000 BC, with waves of linguistic expansion following the progression of agriculture in Europe. Although it has attracted substantive attention and discussions, the datings it proposes are at odds with the linguistic timeframe for Proto-Indo-European and with genetic data, which do not find evidence for Anatolian origins in the Indian genepool. In general, the prestige associated with a specific language or dialect and its progressive dominance over others can be explained by the access to a natural resource unknown or unexploited until then by its speakers, which is thought to be horse-based pastoralism for Indo-European speakers rather than crop cultivation.
A notable third possibility, which has gained renewed attention since the 2010s, is the "Near Eastern model", also known as the Armenian hypothesis. It was proposed by linguists Tamaz V. Gamkrelidze and Vyacheslav Ivanov in the early 1980s, postulating connections between Indo-European and Caucasian languages based on the disputed glottalic theory and connected to archaeological findings by Grogoriev. Some recent DNA-research has led to renewed suggestions of the possibility of a Caucasian or Iranian homeland for archaic or 'proto-proto-Indo-European' (also called 'Indo-Anatolian' or 'Indo-Hittite' in the literature), the common ancestor of both Anatolian languages and early proto-IE (from which Tocharian and all other early branches split-off). These suggestions are disputed in other recent publications, which still locate the origin of the ancestor of proto-Indo-European in the Eastern European/Eurasian steppe or from a hybridization of both steppe and Northwest-Caucasian languages, while "[a]mong comparative linguists, a Balkan route for the introduction of Anatolian IE is generally considered more likely than a passage through the Caucasus, due, for example, to greater Anatolian IE presence and language diversity in the west."
Outlier theories.
A number of other theories have been proposed, most of which have little or no academic currency today (see discussion below):
Theoretical considerations.
Traditionally homelands of linguistic families are proposed based on evidence from comparative linguistics coupled with evidence of historical populations and migrations from archaeology. Today, genetics via DNA samples is increasingly used in the study of ancient population movements.
Reconstructed vocabulary.
Through comparative linguistics it is possible to reconstruct the vocabulary found in the proto-language, and in this way achieve knowledge of the cultural, technological and ecological context that the speakers inhabited. Such a context can then be compared with archaeological evidence. This vocabulary includes, in the case of (late) PIE, which is based on the post-Anatolian and post-Tocharian IE-languages:
Zsolt Simon notes that, although it can be useful to determine the period when the Proto-Indo-European language was spoken, using the reconstructed vocabulary to locate the homeland may be flawed, since we do not know whether Proto-Indo-European speakers knew a specific concept because it was part of their environment or because they had heard of it from other peoples they were interacting with.
Uralic, Caucasian and Semitic borrowings.
Proto-Finno-Ugric and PIE have a lexicon in common, generally related to trade, such as words for "price" and "draw, lead". Similarly, "sell" and "wash" were borrowed in Proto-Ugric. Although some have proposed a common ancestor (the hypothetical Nostratic macrofamily), this is generally regarded as the result of intensive borrowing, which suggests that their homelands were located near each other. Proto-Indo-European also exhibits lexical loans to or from Caucasian languages, particularly Proto-Northwest Caucasian and Proto-Kartvelian, which suggests a location close to the Caucasus.
Gramkelidze and Ivanov, using the now largely unsupported glottalic theory of Indo-European phonology, also proposed Semitic borrowings into Proto-Indo-European, suggesting a more southern homeland to explain these borrowings. According to Mallory and Adams, some of these borrowings may be too speculative or from a later date, but they consider the proposed Semitic loans "*táwros" 'bull' and "*wéyh₁on-" 'wine; vine' to be more likely. Anthony notes that those Semitic borrowings may also have occurred through the advancement of Anatolian farmer cultures via the Danube valley into the steppe zone.
Genesis of Indo-European languages.
Phases of Proto-Indo-European.
According to Anthony, the following terminology may be used:
The Anatolian languages are the first Indo-European language family to have split off from the main group. Due to the archaic elements preserved in the Anatolian languages, they may be a "cousin" of Proto-Indo-European, instead of a "daughter", but Anatolian is generally regarded as an early offshoot of the Indo-European language group.
The Indo-Hittite hypothesis postulates a common predecessor for both the Anatolian languages and the other Indo-European languages, called Indo-Hittite or Indo-Anatolian. Although PIE had predecessors, the Indo-Hittite hypothesis is not widely accepted, and there is little to suggest that it is possible to reconstruct a proto-Indo-Hittite stage that differs substantially from what is already reconstructed for PIE.
Anthony (2019) suggests a derivation of the proto-Indo-European language mainly from a base of languages spoken by Eastern European Hunter-Gatherers living at the Volga steppes, with influences from languages spoken by northern Caucasus hunter-gatherers who migrated from the Caucasus to the lower Volga basin, in addition to a possible later and more minor influence from the language of the Maikop culture to the south (which is hypothesized to have belonged to the North Caucasian family) in the later Neolithic or Bronze Age involving little genetic impact.
Dating the split-offs of the main branches.
Using a mathematical analysis borrowed from evolutionary biology, Don Ringe and Tandy Warnow propose the following tree of Indo-European branches:
David Anthony, following the methodology of Ringe and Warnow, proposes the following sequence:
Steppe hypothesis.
Gimbutas' Kurgan hypothesis.
In the early 1980s, a mainstream consensus had emerged among Indo-Europeanists in favour of the "Kurgan hypothesis" (named after the kurgans, burial mounds, of the Eurasian steppes) placing the Indo-European homeland in the Pontic–Caspian steppe of the Chalcolithic. This was not least due to the influence of the "Journal of Indo-European Studies", edited by J. P. Mallory, that focused on the ideas of Marija Gimbutas and offered some improvements.
Gimbutas had created a modern variation on the traditional invasion theory in which the Indo-Europeans were a nomadic tribe in Eastern Ukraine and Southern Russia and expanded on horseback in several waves during the 3rd millennium BC. Their expansion coincided with the taming of the horse. Leaving archaeological signs of their presence (see Corded Ware culture), they subjugated the peaceful European Neolithic farmers of Gimbutas' Old Europe. As Gimbutas' beliefs evolved, she put increasing emphasis on the patriarchal, patrilineal nature of the invading culture, sharply contrasting it with the supposedly egalitarian, if not matrilineal culture of the invaded, to the point of formulating essentially a feminist archaeology. Her interpretation of Indo-European culture found genetic support in remains from the Neolithic culture of Scandinavia, where DNA from bone remains in Neolithic graves indicated that the megalith culture was either matrilocal or matrilineal, as the people buried in the same grave were related through the women. Likewise, there is a tradition of remaining matrilineal traditions among the Basque, a people whose language and culture is widely supposed to be descended from a pre indo-European relict.
Archaeology.
The Gimbutas-Mallory Kurgan hypothesis seeks to identify the source of the Indo-European language expansion as a succession of migrations from the Pontic–Caspian steppe, originating in the area encompassed by the Sredny Stog culture (c. 4500 BC). J. P. Mallory, dating the migrations later, to c. 4000 BC, and putting less insistence on their violent or quasi-military nature, essentially modified Gimbutas' theory making it compatible with a less gender-political narrative. David Anthony, focusing mostly on the evidence for the domestication of horses and the presence of wheeled vehicles, came to regard specifically the Yamna culture, which replaced the Sredny Stog culture around 3500 BC, as the most likely candidate for the Proto-Indo-European speech community.
Anthony describes the spread of cattle-raising from early farmers in the Danube Valley into the Ukrainian steppes in the 6th–5th millennium BC, forming a cultural border with the hunter-gatherers whose languages may have included archaic PIE. Anthony notes that domesticated cattle and sheep probably didn't enter the steppes from the Transcaucasia, since the early farming communities there were not widespread, and separated from the steppes by the glaciated Caucasus. Subsequent cultures developed in this area which adopted cattle, most notably the Cucuteni-Trypillian culture.
Parpola regards the Tripolye culture as the birthplace of wheeled vehicles, and therefore as the homeland for Late PIE, assuming that Early PIE was spoken by Skelya pastoralists (early Sredny Stog culture) who took over the Tripolye culture at c. 4300–4000 BC. On its eastern border lay the Sredny Stog culture (4400–3400 BC), whose origins are related to "people from the east, perhaps from the Volga steppes". It plays a central role in Gimbutas' Kurgan hypothesis, and coincides with the spread of early PIE across the steppes and into the Danube valley (c. 4000 BC), leading to the collapse of Old Europe. Hereafter the Maykop culture suddenly arose, Tripolye towns grew strongly, and eastern steppe people migrated to the Altai mountains, founding the Afanasevo culture (3300 to 2500 BC).
Vocabulary.
The core element of the steppe hypothesis is the identification of the proto-Indo-European culture as a nomadic pastoralist society that did not practice intensive agriculture. This identification rests on the fact that vocabulary related to cows, to horses and horsemanship, and to wheeled vehicles can be reconstructed for all branches of the family, whereas only a few agricultural vocabulary items are reconstructable, suggesting a gradual adoption of agriculture through contact with non-Indo-Europeans. If this evidence and reasoning is accepted, the search for the Indo-European proto-culture has to involve searching for the earliest introduction of domesticated horses and wagons into Europe.
Responding to these arguments, proponents of the Anatolian hypothesis Russell Gray and Quentin Atkinson have argued that the different branches could have independently developed similar vocabulary based on the same roots, creating the false appearance of shared inheritance – or alternatively, that the words related to wheeled vehicle might have been borrowed across Europe at a later date. Proponents of the Steppe hypothesis have argued this to be highly unlikely, and to break with the established principles for reasonable assumptions when explaining linguistic comparative data.
Another source of evidence for the steppe hypothesis is the presence of what appears to be many shared loanwords between Uralic languages and proto-Indo-European, suggesting that these languages were spoken in adjacent areas. This would have had to take place a good deal further north than the Anatolian or Near Eastern scenarios would allow. According to Kortlandt, Indo-Uralic is the pre-PIE, postulating that Indo-European and Uralic share a common ancestor. According to Kortlandt, "Indo-European is a branch of Indo-Uralic which was radically transformed under the influence of a North Caucasian substratum when its speakers moved from the area north of the Caspian Sea to the area north of the Black Sea." Anthony notes that the validity of such deep relationships cannot be reliably demonstrated due to the time-depth involved, and also notes that the similarities may be explained by borrowings from PIE into proto-Uralic. Yet, Anthony also notes that the North Caucasian communities "were southern participants in the steppe world".
Genetics.
Three genetic studies in 2015 gave support to the Kurgan theory of Gimbutas regarding the Indo-European "Urheimat". According to those studies, Y chromosome haplogroups R1b and R1a, now the most common in Europe (R1a is also common in South Asia) would have expanded from the Russian steppes, along with the Indo-European languages; they also detected an autosomal component present in modern Europeans which was not present in Neolithic Europeans, which would have been introduced with paternal lineages R1b and R1a, as well as Indo-European languages.
Many geneticists consider Haplogroup R1a to be associated with the origins and spread of the Indo-Europeans. R1a1 shows a strong correlation with the distribution of the Indo-European languages in Europe and South Asia, being most prevalent in Poland, Russia, and Ukraine, and in central Asia, Afghanistan, Pakistan and India. Two specific subclades dominate, namely R1-Z282 in Eastern-Europe and R1-Z93 in South Asia and South-Siberia. According to Underhill et al. (2014), the initial diversification of R1a took place in the vicinity of Iran, while Pamjav et al. (2012) think that R1a diversified within the Eurasian steppes or the Middle East and Caucasus region.
Paternal lineages R1a and R1b (and paternal haplogroup I) have been found in Yamnaya (and other proposed early Indo-European) remains, as well as in remains from the preceding Mesolithic (hunter gatherer) and Neolithic peoples of the Eastern European steppe.
The subclade R1a1a (R-M17 or R-M198) is the R1a subclade most commonly associated with Indo-European speakers.
Ornella Semino et al. propose a postglacial (Holocene) spread of the R1a R1a1 haplogroup from north of the Black Sea during the time of the Late Glacial Maximum, which was subsequently magnified by the expansion of the Kurgan culture into Europe and eastward.
Late Neolithic and Bronze Age Central Europeans surveyed in ancient DNA studies conclusively showed a mix of Western Hunter-Gatherers (WHG), Anatolian Farmers, and Pontic Steppe Hunter-Gatherers ancestry. Individuals from the Yamnaya culture had themselves a mix from Eastern Hunter-Gatherers (EHG) and Caucasus Hunter-Gatherer (CHG) ancestry (a mating network going from the Caucasus Mountains, parts of eastern Anatolia, and the western Iranian plateau). In 2015, a large-scale ancient DNA study published in "Nature" found evidence of a "massive migration" from the Pontic-Caspian steppe to Central Europe that took place about 4,500 years ago. It found that individuals from the Central European Corded Ware culture (3rd millennium BC) were genetically closely related to individuals from the Yamnaya culture. The authors concluded that their "results provide support for the theory of a steppe origin of at least some of the Indo-European languages of Europe", in this case pre-Italo-Celtic and pre-Germanic.
However, the folk migration model cannot be the only diffusion theory for all linguistic families, as the Yamnaya ancestry component is particularly concentrated in Europe in the northwestern parts of the continent. Other models for languages like Proto-Greek are still debated. The steppe genetic component is more diffuse in studied Mycenaean populations: if they came from elsewhere, Proto-Greek speakers were certainly a minority in a sea of populations which had been familiar with agriculture for 4000 years. Some propose that they gained progressive prominence through a cultural expansion by elite influence. But if high correlations can be proven in ethnolinguistic or remote communities, genetics does not always equate with language, and archaeologists have argued that although such a migration might have taken place, it does not necessarily explain either the distribution of archaeological cultures or the spread of the Indo-European languages.
An analysis by David Anthony (2019) suggests a genetic origin of Proto-Indo-Europeans (associated with the Yamnaya culture) in the Eastern European steppe north of the Caucasus, deriving from a mixture of Eastern European hunter-gatherers and hunter-gatherers from the Caucasus. Anthony also suggests that the Proto-Indo-European language formed mainly from a base of languages spoken by Eastern European hunter-gathers with influences from languages of northern Caucasus hunter-gatherers, in addition to a possible later and more minor influence from the language of the Maykop culture to the south (which is hypothesized to have belonged to the North Caucasian languages) in the later Neolithic or Bronze Age, involving little genetic impact.
Anatolian hypothesis.
Theory.
The main competitor to the Kurgan hypothesis is the Anatolian hypothesis advanced by Colin Renfrew in 1987. It couples the spread of the Indo-European languages to the hard fact of the Neolithic spread of farming from the Near East, stating that the Indo-European languages began to spread peacefully into Europe from Asia Minor from around 7000 BC with the Neolithic advance of farming ("wave of advance"). The expansion of agriculture from the Middle East would have diffused three language families: Indo-European toward Europe, Dravidian toward Pakistan and India, and Afro-Asiatic toward Arabia and North Africa.
According to Renfrew (2004), the spread of Indo-European proceeded in the following steps:
Reacting to criticism, Renfrew revised his proposal to the effect of taking a pronounced Indo-Hittite position. Renfrew's revised views place only Pre-Proto-Indo-European in 7th millennium BC Anatolia, proposing as the homeland of Proto-Indo-European proper the Balkans around 5000 BC, explicitly identified as the "Old European culture" proposed by Marija Gimbutas. He thus still situates the original source of the Indo-European language family in Anatolia c. 7000 BC. Reconstructions of a Bronze Age PIE society based on vocabulary items like "wheel" do not necessarily hold for the Anatolian branch, which appears to have separated from PIE at an early stage, prior to the invention of wheeled vehicles.
Following the publication of several studies on ancient DNA in 2015, Colin Renfrew has accepted the reality of migrations of populations speaking one or several Indo-European languages from the Pontic steppe towards Northwestern Europe.
Objections.
Dating.
The main objection to this theory is that it requires an unrealistically early date. According to linguistic analysis, the Proto-Indo-European lexicon seems to include words for a range of inventions and practices related to the Secondary Products Revolution, which post-dates the early spread of farming. On lexico-cultural dating, Proto-Indo-European cannot be earlier than 4000 BC.
Farming.
The idea that farming was spread from Anatolia in a single wave has been revised. Instead it appears to have spread in several waves by several routes, primarily from the Levant. The trail of plant domesticates indicates an initial foray from the Levant by sea. The overland route via Anatolia seems to have been most significant in spreading farming into south-east Europe.
Farming developed independently in the eastern fertile crescent. Non-Indo-European languages appear to be associated with the spread of farming from the Near East into North Africa and the Caucasus. According to Lazaridis et al. (2016), farming developed independently both in the Levant and in the eastern Fertile Crescent. After this initial development, the two regions and the Caucasus interacted, and the chalcolithic north-west Iranian population appears to be a mixture of Iranian Neolithic, Levant, and Caucasus hunter-gatherers. According to Lazaridis et al. (2016), "farmers related to those from Iran spread northward into the Eurasian steppe; and people related to both the early farmers of Iran and to the pastoralists of the Eurasian steppe spread eastward into South Asia". They further note that ANI "can be modelled as a mix of ancestry related to both early farmers of western Iran and to people of the Bronze Age Eurasian steppe", which makes it unlikely that the Indo-European languages in India are derived from Anatolia. Mascarenhas et al. (2015) note that the expansion of Z93 from Transcaucasia into South Asia is compatible with "the archeological records of eastward expansion of West Asian populations in the 4th millennium BC culminating in the so-called Kura-Araxes migrations in the post-Uruk IV period".
Alignment with the steppe theory.
According to Alberto Piazza "[i]t is clear that, genetically speaking, peoples of the Kurgan steppe descended at least in part from people of the Middle Eastern Neolithic who immigrated there from Turkey." According to Piazza and Cavalli-Sforza, the Yamna culture may have been derived from Middle Eastern Neolithic farmers who migrated to the Pontic steppe and developed pastoral nomadism:
Wells agrees with Cavalli-Sforza that there is ""some" genetic evidence for migration from the Middle East":
Southern archaic PIE-homeland hypothesis.
Armenian hypothesis.
Gamkrelidze and Ivanov held that the "Urheimat" was south of the Caucasus, specifically, "within eastern Anatolia, the southern Caucasus and northern Mesopotamia" in the fifth to fourth millennia BC. Their proposal was based on a disputed theory of glottal consonants in PIE. According to Gamkrelidze and Ivanov, PIE words for material culture objects imply contact with more advanced peoples to the south, the existence of Semitic loan-words in PIE, Kartvelian (Georgian) borrowings from PIE, some contact with Sumerian, Elamite and others. However, given that the glottalic theory never caught on and there was little archaeological support, the Gamkrelidze and Ivanov theory did not gain support until Renfrew's Anatolian theory revived aspects of their proposal.
Gamkrelidze and Ivanov proposed that the Greeks moved west across Anatolia to their present location, a northward movement of some IE speakers that brought them into contact with the Finno-Ugric languages, and suggested that the Kurgan area, or better "Black Sea and Volga steppe", was a secondary homeland from which the western IE languages emerged.
South Caucasus/Iranian suggestions.
Recent DNA research which shows that the steppe-people derived from a mix of Eastern Hunter-Gatherers (EHG) and Caucasian Hunter-Gatherers, has led to renewed suggestions of the possibility of a Caucasian, or even Iranian, homeland for an archaic proto-Indo-European, the common ancestor of both Anatolian languages and all other Indo-European languages. It is argued that this may lend support to the Indo-Hittite hypothesis, according to which both proto-Anatolian and proto-Indo-European split-off from a common mother language "no later than the 4th millennium BCE."
Damgaard and Wang state that the steppe-model is the dominant model, and does account for a steppe-origin of the Anatolian languages. Damgaard notes that "Among comparative linguists, a Balkan route for the introduction of Anatolian IE is generally considered more likely than a passage through the Caucasus, due, for example, to greater Anatolian IE presence and language diversity in the west." Kloekhorst argues that the Anatolian languages have preserved archaisms which are also found in proto-Uralic, providing strong evidence for a steppe-origin of PIE. 
Gallego-Llorente et al. (2016) conclude that Iranian populations are not a likelier source of the 'southern' component in the Yamnaya than Caucasus hunter-gatherers. According to Wang et al. (2019), the typical steppe-ancestry, as an even mix between EHG and CHG, may result from "an existing natural genetic gradient running from EHG far to the north to CHG/Iran in the south," or it may be explained as "the result of Iranian/CHG-related ancestry reaching the steppe zone independently and prior to a stream of AF [Anatolian Farmer] ancestry." According to Margaryan et al. (2017) there was a rapid increase of the south Caucasian population at the end of the Last Glacial Maximum, about 18,000 years ago, while Fu et al. (2016) conclude that Near East and Caucasus people probably migrated to Europe already during the Mesolithic, around 14,000 years ago. Narasimhan et al. (2019) conclude that people "characteristic of northern Caucasus and Iranian plateau hunter-gatherers" reached India before 6000 BCE, before the advent of farming in northern India.
Bomhard's hybrid North Caspian/Caucasian hypothesis.
Bomhard's Caucasian substrate hypothesis proposes an origin ("Urheimat") in a Central Asian or North Caspian region of the steppe for Indo-Uralic (a proposed common ancestor of Indo-European and Uralic). Bomhard elaborates on Johanna Nichols "Sogdiana hypothesis", and Kortlandt's ideas of an Indo-Uralic proto-language, proposing an "Urheimat" north or east of the Caspian Sea, of a Eurasiatic language which was imposed on a population which spoke a Northwest Caucasian language, with this mixture producing proto-Indo-European.
Anthony: Steppe homeland with south Caspian CHG-influences.
David Anthony (2019) criticizes the Southern/Caucasian homeland hypothesis (including the suggestions of Reich, Kristiansen, and Wang). Instead, Anthony argues that the roots of the proto-Indo-European language formed mainly from a base of languages spoken by Eastern European hunter-gatherers, with some influences from the languages of Caucasus hunter-gatherers. Anthony rejects the possibility that the Bronze Age Maykop people of the Caucasus were a southern source of language and genetics of Indo-European. Referring to Wang et al. (2019), he notes that the Anatolian Farmer component in the Yamnaya-ancestry came from European farmers, not from the Maykop, which had too much Anatolian farmer ancestry to be ancestral to the Yamnaya-population. Anthony also notes that the paternal lineages of the Yamnaya, which were rich in R1b, were related to those of earlier Eastern European hunter-gatherers, rather than those of southern or Caucasus peoples such as the Maykop. Anthony rejects the possibility that the Bronze Age Maykop people of the Caucasus were a southern source of language and genetics of Indo-European. According to Anthony, referring to Wang et al. (2019), the Maykop culture had little genetic impact on the Yamnaya, whose paternal lineages were found to differ from those found in Maykop remains, but were instead related to those of earlier Eastern European hunter-gatherers. Also, the Maykop (and other contemporary Caucasus samples), along with CHG from this date, had significant Anatolian Farmer ancestry "which had spread into the Caucasus from the west after about 5000 BC", while the Yamnaya had a lower percentage which does not fit with a Maykop origin. Partly for these reasons, Anthony concludes that Bronze Age Caucasus groups such as the Maykop "played only a minor role, if any, in the formation of Yamnaya ancestry." According to Anthony, the roots of Proto-Indo-European (archaic or proto-proto-Indo-European) were mainly in the steppe rather than the south. Anthony considers it likely that the Maykop spoke a Northern Caucasian language not ancestral to Indo-European.
Anthony proposes that the Yamnaya derived mainly from Eastern European hunter-gatherers (EHG) from the steppes, and undiluted Caucasus hunter-gatherers (CHG) from northwestern Iran or Azerbaijan, similar to the Hotu cave population, who mixed in the Eastern European steppe north of the Caucasus. According to Anthony, hunting-fishing camps from the lower Volga, dated 6200–4500 BCE, could be the remains of people who contributed the CHG-component, migrating westwards along the coast of the Caspian Sea, from an area south-east of the Caspian Sea. They mixed with EHG-people from the north Volga steppes, and the resulting culture contributed to the Sredny Stog culture, a predecessor of the Yamnaya culture.
Other hypotheses.
Baltic homeland.
Lothar Kilian and Marek Zvelebil have proposed a 6th millennium BC or later origin of the IE-languages in Northern Europe, as a creolisation of migrating Neolithic farmers settling in northern Europe, and mixing with indigenous Mesolithic hunter-gatherer communities. The steppe theory is compatible with the argument that the PIE homeland must have been larger, because the "Neolithic creolisation hypothesis" allows the Pontic-Caspian region to have been part of PIE territory.
Palaeolithic Continuity Theory.
The "Paleolithic Continuity Paradigm" is a hypothesis suggesting that the Proto-Indo-European language (PIE) can be traced back to the Upper Paleolithic, several millennia earlier than the Chalcolithic or at the most Neolithic estimates in other scenarios of Proto-Indo-European origins. Its main proponents are Marcel Otte, Alexander Häusler, and Mario Alinei.
The PCT posits that the advent of Indo-European languages should be linked to the arrival of "Homo sapiens" in Europe and Asia from Africa in the Upper Paleolithic. Employing "lexical periodization", Alinei arrives at a timeline deeper than even that of Colin Renfrew's Anatolian hypothesis.
Since 2004, an informal workgroup of scholars who support the Paleolithic Continuity hypothesis has been held online. Apart from Alinei himself, its leading members (referred to as "Scientific Committee" in the website) are linguists Xaverio Ballester (University of Valencia) and Francesco Benozzo (University of Bologna). Also included are prehistorian Marcel Otte (Université de Liège) and anthropologist Henry Harpending (University of Utah).
It is not listed by Mallory among the proposals for the origins of the Indo-European languages that are widely discussed and considered credible within academia.
Fringe theories.
Hyperborea.
Soviet Indologist Natalia R. Guseva and Soviet etnographer S.V Zharnikova, influenced by Tilak's The Arctic Home in the Vedas, argued for a northern Urals Arctic homeland of the Indo-Aryan and Slavic people; their ideas were popularized by Russian nationalists.
Out of India theory.
The Indigenous Aryans theory, also known as the Out of India theory, proposes an Indian origin for the Indo-European languages. The languages of northern India and Pakistan, including Hindi and the historically and culturally significant liturgical language Sanskrit, belong to the Indo-Aryan branch of the Indo-European language family. The Steppe model, rhetorically presented as an "Aryan invasion," has been opposed by Hindu revivalists and Hindu nationalists, who argue that the Aryans were indigenous to India, and some, such as B.B. Lal, Koenraad Elst and Shrikant Talageri, have proposed that Proto-Indo-European itself originated in northern India, either with or shortly before the Indus Valley Civilisation. This "Out of India" theory is not regarded as plausible in mainstream scholarship.