Western Steppe Herders

Haak et al. (2015), Massive migration from the steppe was a source for Indo-European languages in Europe, a ground-breaking study published in Nature, found the ancestry of the people of the Yamnaya culture to be a mix of Eastern Hunter-Gatherer and another unidentified population. All seven Yamnaya males surveyed were found to belong to subclade R-M269 of haplogroup R1b. R1b had earlier been detected among EHGs living further north.[2]

The study found that people of the Corded Ware culture were of approximately 75% WSH ancestry, being descended from Yamnaya people who had mixed with Middle Neolithic Europeans. This suggested that the Yamnaya people embarked on a massive expansion ca. 3,000 BC, which might have played a role in the dispersal of Indo-European languages in Europe. At this time, Y-DNA haplogroups common among Early European Farmers (EEFs), such as G2a, disappear almost entirely in Central Europe, and is replaced by haplotypes of R1b and R1a, which are common among WSH. EEF mtDNA decreases significantly as well, and is replaced by WSH types, suggesting that the Yamnaya expansion was carried out by both males and females. In the aftermath of the Yamnaya expansion there appears to have been a resurgence of EEF and Western Hunter-Gatherer (WHG) ancestry in Central Europe, as this is detected in samples from the Bell Beaker culture and its successor the Unetice culture.[2] The Bell Beaker culture had about 50% WSH ancestry.[7]

All modern European populations can be modeled as a mixture of WHG, EEF and WSH. WSH ancestry is more common in Northern Europe than Southern Europe. Of modern populations surveyed in the study, Norwegians were found to have the largest amount of WSH ancestry, which among them exceeded 50%.[2]

Allentoft et al. (2015), Population genomics of Bronze Age Eurasia, published in Nature in June 2015 examined the Y-DNA of five Yamnaya males. Four belonged to types of R1b1a2, while one belonged to I2a2a1b1b. The study found that the Neolithic farmers of Central Europe had been "largely replaced" by Yamnaya people around 3,000 BC. This replacement altered not only the genetic landscape, but also the cultural landscape of Europe in many respects.[8]

It was discovered that the people of the contemporary Afanasievo culture of southern Siberia were "genetically indistinguishable" from the Yamnaya and thus largely of WSH ancestry. People of the Corded Ware culture, the Bell Beaker culture, the Unetice culture and the Nordic Bronze Age displayed close genetic affinity to WSH. The authors of the study suggested that the Sintashta culture of Central Asia emerged as a result of an eastward migration from Central Europe of Corded Ware people with both WSH and European Neolithic farmer ancestry.[8]

A genetic study published in Nature Communications in November 2015, found that the WSHs were descended from admixture between EHGs and Caucasian Hunter-Gatherers (CHGs). CHGs were found to have split off from WHGs ca. 43,000 BC, and to have split off from EEFs ca. 23,000 BC.[9]

A genetic study published in Nature in November 2015 found that the people of the Poltavka culture, Potapovka culture and Srubnaya culture were closely related and largely of WSH descent, although the Srubnaya carried more EEF ancestry (about 17%) than the rest. Like in Yamnaya, males of Poltavka mostly carried types of R1b, while Srubnaya males carried types of R1a.(Mathieson et al. 2015)

The study found that most modern Europeans could be modelled as a mixture between WHG, EEF and WSH.[lower-alpha 3]

A genetic study published in Nature in July 2016 found that WSHs were a mixture of EHGs and "a population related to people of the Iran Chalcolithic". EHGs were modeled as being of 75% Ancient North Eurasian (ANE) descent. A significant presence of WSH ancestry among populations of South Asia was detected. Here WSH ancestry peaked at 50% among the Kalash people, which is a level similar to modern populations of Northern Europe.[10]

A genetic study published in Nature in August 2017 examined the genetic origins of the Mycenaeans and the Minoans. Contrary to the Minoans, the Mycenaeans were found to harbor about 15% WSH ancestry. It was found that Mycenaeans could be modelled as a mixture of WSH and Minoan ancestry. This suggests that the Mycenaeans arrived in Greece as a southern wing of the Indo-European migrations.[11]

A genetic study published in Nature in February 2018 examined the entry of WSH ancestry into the British Isles. WSH ancestry was found to have been carried into the British Isles by the Bell Beaker culture in the 3rd millennium BC. The migrations of Bell Beakers were accompanied with "a replacement of ~90% of Britain's gene pool within a few hundred years". The gene pool in the British Isles had previously been dominated by EEFs with slight WHG admixture.[lower-alpha 4]

Y-DNA in parts of the modern British Isles belongs almost entirely to R-M269, a WSH lineage, which is thought to have been brought to the isles with Bell Beakers.[12]

A genetic study published in Nature in February 2018 noted that the modern population of Europe can largely be modeled as a mixture between EHG, WHG, WSH and EEF.[lower-alpha 5]

The study examined individuals from the Globular Amphora culture, who bordered the Yamnaya. Globular Amphora culture people were found to have no WSH ancestry, suggesting that cultural differences and genetic differences were connected.[7]

Notably, WSH ancestry was detected among two individuals buried in modern-day Bulgaria ca. 4,500 BC. This showed that WSH ancestry appeared outside of the steppe 2,000 years earlier than previously believed.[7]

A genetic study published in the Proceedings of the National Academy of Sciences of the United States of America in November 2018 examined the presence of WSH ancestry in the Mongolian Plateau. A number of remains from Late Bronze Age individuals buried around Lake Baikal were studied. These individuals had only 7% WSH ancestry, suggesting that pastoralism was adopted on the Eastern Steppe through cultural transmission rather than genetic displacement.[3]

The study found that WSH ancestry found among Late Bronze Age populations of the south Siberia such as the Karasuk culture was transmitted through the Andronovo culture rather than the earlier Afanasievo culture, whose genetic legacy in the region by this time was virtually non-existent.[3]

A genetic study published in Nature Communications in February 2019 compared the genetic origins of the Yamnaya culture and the Maikop culture. It found that most of the EEF ancestry found among the Yamnaya culture was derived from the Globular Amphora culture and the Cucuteni–Trypillia culture of Eastern Europe.[13][14] Total EEF ancestry among the Yamnaya has been estimated at 10-18%. Given the high amount of EEF ancestry in the Maikop culture, this makes it impossible for the Maikop culture to have been a major source of CHG ancestry among the WSHs. Admixture from the CHGs into the WSHs must thus have happened at an earlier date.[14]

A genetic study published in Science in March 2019 analyzed the process by which WSH ancestry entered the Iberian Peninsula. The earliest evidence of WSH ancestry here was found from an individual living in Iberia in 2,200 BC in close proximity with native populations. By 2,000 BC, the native Y-DNA of Iberia (H, G2 and I2) had been almost entirely replaced with single WSH lineage, R-M269. mtDNA in Iberia at this time was however still mostly of native origin, affirming that the entry of WSH ancestry in Iberia was primarily male-driven.[lower-alpha 6]

Narasimhan et al (2019) harvtxt error: no target: CITEREFNarasimhan_et_al2019 (help), The Genomic Formation of South and Central Asia, published in Science in September 2019, found a large amount of WSH ancestry among Indo-European-speaking populations throughout Eurasia. This lent support to the theory that the Yamnaya people were Indo-European-speaking.[4]

The study found people of the Corded Ware, Srubnaya, Sintashta and Andronovo cultures to be a closely related group almost wholly of WSH ancestry, but with slight European Middle Neolithic admixture. These results further underpinned the notion that the Sintashta culture emerged as an eastward migration of Corded Ware peoples with mostly WSH ancestry back into the steppe. Among early WSHs, R1b is the most common Y-DNA lineage, while R1a (particularly R1a1a1b2) is common among later groups of Central Asia, such as Andronovo and Srubnaya.[4]

West Siberian Hunter-Gatherers (WSGs), a distinct archaeogenetic lineage, was discovered in the study. These were found to be of about 30% EHG ancestry, 50% ANE ancestry, and 20% East Asian ancestry. It was noticed that WSHs during their expansion towards the east gained a slight (ca. 8%) admixture from WSGs.[4]

It was found that there was a significant infusion of WSH ancestry into Central Asia and South Asia during the Bronze Age. WSH ancestry was found have been almost completely absent from earlier samples in southern Central Asia in the 3rd millennium BC.[lower-alpha 7]

During the expansion of WSHs from Central Asia towards South Asia in the Bronze Age, an increase in South Asian agriculturalist ancestry among WSHs was noticed. Among South Asian populations, WSH ancestry is particularly high among Brahmins and Bhumihars. WSH ancestry was thus expected to have spread into India with the Vedic culture.[4]

In February 2019, an analysis by David W. Anthony of the recent genetic data on WSHs was published in the Journal of Indo-European Studies. An updated version of this analysis was later published in the book Dispersals and Diversification: Linguistic and Archaeological Perspectives on the Early Stages of Indo-European, by BRILL. Anthony notes that WSHs display genetic continuity between the paternal lineages of the Dnieper-Donets culture and the Yamnaya culture, as the males of both cultures have been found to have been mostly carriers of R1b, and to a lesser extent I2.[7]

While the mtDNA of the Dnieper-Donets people is exclusively types of U, which is associated with EHGs and WHGs, the mtDNA of the Yamnaya also includes types frequent among CHGs and EEFs. Anthony notes that WSH had earlier been found among the Sredny Stog culture and the Khvalynsk culture, who preceded the Yamnaya culture on the Pontic–Caspian steppe. The Sredny Stog were mostly WSH with slight EEF admixture, while the Khvalynsk living further east were purely WSH. Anthony also notes that unlike their Khvalynsk predecessors, the Y-DNA of the Yamnaya is exclusively EHG and WHG. This implies that the leading clans of the Yamnaya were of EHG and WHG origin.[17] Because the slight EEF ancestry of the WSHs has been found to be derived from Central Europe, and because there is no CHG Y-DNA detected among the Yamnaya, Anthony notes that it is impossible for the Maikop culture to have contributed much to the culture or CHG ancestry of the WSHs. Anthony suggests that admixture between EHGs and CHGs first occurred on the eastern Pontic-Caspian steppe around 5,000 BC, while admixture with EEFs happened in the southern parts of the Pontic-Caspian steppe sometime later.[5]

Forensic facial reconstructions of three Yamnaya males, made in the Soviet Union in the 1930s

As Yamnaya Y-DNA is exclusively of the EHG and WHG type, Anthony notes that the admixture must have occurred between EHG and WHG males, and CHG and EEF females. Anthony cites this as additional evidence that the Indo-European languages were initially spoken among EHGs living in Eastern Europe. On this basis, Anthony concludes that the Indo-European languages whom the WSHs brought with them were initially the result of "a dominant language spoken by EHGs that absorbed Caucasus-like elements in phonology, morphology, and lexicon".(spoken by CHGs)[5]