Distribution of haplogroup R1b in Europe
R1b is the most common haplogroup in Western Europe, reaching over 80% of the population in Ireland, the Scottish Highlands, western Wales, the Atlantic fringe of France, the Basque country and Catalonia. It is also common in Anatolia and around the Caucasus, in parts of Russia and in Central and South Asia. Besides the Atlantic and North Sea coast of Europe, hotspots include the Po valley in north-central Italy (over 70%), Armenia (35%), the Bashkirs of the Urals region of Russia (50%), Turkmenistan (over 35%), the Hazara people of Afghanistan (35%), the Uyghurs of North-West China (20%) and the Newars of Nepal (11%). R1b-V88, a subclade specific to sub-Saharan Africa, is found in 60 to 95% of men in northern Cameroon.
Paleolithic mammoth hunters
Haplogroup R* originated in North Asia just before the Last Glacial Maximum (26,500-19,000 years ago). This haplogroup has been identified in the remains of a 24,000 year-old boy from the Altai region, in south-central Siberia (Raghavan et al. 2013). This individual belonged to a tribe of mammoth hunters that may have roamed across Siberia and parts of Europe during the Paleolithic. Autosomally this Paleolithic population appears to have contributed mostly to the ancestry of modern Europeans and South Asians, the two regions where haplogroup R also happens to be the most common nowadays (R1b in Western Europe, R1a in Eastern Europe, Central and South Asia, and R2 in South Asia).
The oldest forms of R1b (M343, P25, L389) are found dispersed at very low frequencies from Western Europe to India, a vast region where could have roamed the nomadic R1b hunter-gatherers during the Ice Age. The three main branches of R1b1 (R1b1a, R1b1b, R1b1c) all seem to have stemmed from the Middle East. The southern branch, R1b1c (V88), is found mostly in the Levant and Africa. The northern branch, R1b1a (P297), seems to have originated around the Caucasus, eastern Anatolia or northern Mesopotamia, then to have crossed over the Caucasus, from where they would have invaded Europe and Central Asia. R1b1b (M335) has only been found in Anatolia.
Neolithic cattle herders
It has been hypothesized that R1b people (perhaps alongside neighboring J2 tribes) were the first to domesticate cattle in northern Mesopotamia some 10,500 years ago. R1b tribes descended from mammoth hunters, and when mammoths went extinct, they started hunting other large game such as bison and aurochs. With the increase of the human population in the Fertile Crescent from the beginning of the Neolithic (starting 12,000 years ago), selective hunting and culling of herds started replacing indiscriminate killing of wild animals. The increased involvement of humans in the life of aurochs, wild boars and goats led to their progressive taming. Cattle herders probably maintained a nomadic or semi-nomadic existence, while other people in the Fertile Crescent (presumably represented by haplogroups E1b1b, G and T) settled down to cultivate the land or keep smaller domesticates.
The analysis of bovine DNA has revealed that all the taurine cattle (Bos taurus) alive today descend from a population of only 80 aurochs. The earliest evidence of cattle domestication dates from circa 8,500 BCE in the Pre-Pottery Neolithic cultures in the Taurus Mountains. The two oldest archaeological sites showing signs of cattle domestication are the villages of Çayönü Tepesi in southeastern Turkey and Dja’de el-Mughara in northern Iraq, two sites only 250 km away from each other. This is presumably the area from which R1b lineages started expanding – or in other words the “original homeland” of R1b.
The early R1b cattle herders would have split in at least three groups. One branch (M335) remained in Anatolia, but judging from its extreme rarity today wasn’t very successful, perhaps due to the heavy competition with other Neolithic populations in Anatolia, or to the scarcity of pastures in this mountainous environment. A second branch migrated south to the Levant, where it became the V88 branch. Some of them searched for new lands south in Africa, first in Egypt, then colonizing most of northern Africa, from the Mediterranean coast to the Sahel. The third branch (P297), crossed the Caucasus into the vast Pontic-Caspian Steppe, which provided ideal grazing grounds for cattle. They split into two factions: R1b1a1 (M73), which went east along the Caspian Sea to Central Asia, and R1b1a2 (M269), which at first remained in the North Caucasus and the Pontic Steppe between the Dnieper and the Volga. It is not yet clear whether M73 actually migrated across the Caucasus and reached Central Asia via Kazakhstan, or if it went south through Iran and Turkmenistan. In any case, M73 would be a pre-Indo-European branch of R1b, just like V88 and M335.
R1b-M269 (the most common form in Europe) is closely associated with the diffusion of Indo-European languages, as attested by its presence in all regions of the world where Indo-European languages were spoken in ancient times, from the Atlantic coast of Europe to the Indian subcontinent, which comprised almost all Europe (except Finland, Sardinia and Bosnia-Herzegovina), Anatolia, Armenia, European Russia, southern Siberia, many pockets around Central Asia (notably in Xinjiang, Turkmenistan, Tajikistan and Afghanistan), without forgetting Iran, Pakistan, northern India and Nepal. The history of R1b and R1a are intricately connected to each other.
The Levantine & African branch of R1b (V88)
Like its northern counterpart (R1b-M269), R1b-V88 is associated with the domestication of cattle in northern Mesopotamia. Both branches of R1b probably split soon after cattle were domesticated, approximately 10,500 years ago (8,500 BCE). R1b-V88 migrated south towards the Levant and Egypt. The migration of R1b people can be followed archeologically through the presence of domesticated cattle, which appear in central Syria around 8,000-7,500 BCE (late Mureybet period), then in the Southern Levant and Egypt around 7,000-6,500 BCE (e.g. at Nabta Playa and Bir Kiseiba). Cattle herders subsequently spread across most of northern and eastern Africa. The Sahara desert would have been more humid during the Neolithic Subpluvial period (c. 7250-3250 BCE), and would have been a vast savannah full of grass, an ideal environment for cattle herding.
Evidence of cow herding during the Neolithic has shown up at Uan Muhuggiag in central Libya around 5500 BCE, at the Capeletti Cave in northern Algeria around 4500 BCE. But the most compelling evidence that R1b people related to modern Europeans once roamed the Sahara is to be found at Tassili n’Ajjer in southern Algeria, a site famous petroglyphs (rock art) dating from the Neolithic era. Some painting dating from around 3000 BCE depict fair-skinned and blond or auburn haired women riding on cows. The oldest known R1b-V88 sample in Europe is a 6,200 year-old farmer/herder from Catalonia tested by Haak et al. (2015). Autosomally this individual was a typical Near Eastern farmer, possessing just a little bit of Mesolithic West European admixture.
After reaching the Maghreb, R1b-V88 cattle herders could have crossed the Strait of Gibraltar to Iberia, probably accompanied by G2 farmers, J1 and T1a goat herders. These North African Neolithic farmers/herders could have been the ones who established the Almagra Pottery culture in Andalusia in the 6th millennium BCE.
Nowadays small percentages (1 to 4%) of R1b-V88 are found in the Levant, among the Lebanese, the Druze, and the Jews, and almost in every country in Africa north of the equator. Higher frequency in Egypt (5%), among Berbers from the Egypt-Libya border (23%), among the Sudanese Copts (15%), the Hausa people of Sudan (40%), the Fulani people of the Sahel (54% in Niger and Cameroon), and Chadic tribes of northern Nigeria and northern Cameroon (especially among the Kirdi), where it is observed at a frequency ranging from 30% to 95% of men. According to Cruciani et al. (2010) R1b-V88 would have crossed the Sahara between 9,200 and 5,600 years ago, and is most probably associated with the diffusion of Chadic languages, a branch of the Afroasiatic languages. V88 would have migrated from Egypt to Sudan, then expanded along the Sahel until northern Cameroon and Nigeria. However, R1b-V88 is not only present among Chadic speakers, but also among Senegambian speakers (Fula-Hausa) and Semitic speakers (Berbers, Arabs).
R1b-V88 is found among the native populations of Rwanda, South Africa, Namibia, Angola, Congo, Gabon, Equatorial Guinea, Ivory Coast, Guinea-Bissau. The wide distribution of V88 in all parts of Africa, its incidence among herding tribes, and the coalescence age of the haplogroup all support a Neolithic dispersal. In any case, a later migration out of Egypt would be improbable since it would have brought haplogroups that came to Egypt during the Bronze Age, such as J1, J2, R1a or R1b-L23.
The maternal lineages associated with the spread of R1b-V88 in Africa are mtDNA haplogroups J1b, U5 and V, and perhaps also U3 and some H subclades (=> see Retracing the mtDNA haplogroups of the original R1b people).
The North Caucasus and the Pontic-Caspian steppe: the Indo-European link
Modern linguists have placed the Proto-Indo-European homeland in the Pontic-Caspian Steppe, a distinct geographic and archeological region extending from the Danube estuary to the Ural Mountains to the east and North Caucasus to the south. The Neolithic, Eneolithic and early Bronze Age cultures in Pontic-Caspian steppe has been called the Kurgan culture (4200-2200 BCE) by Marija Gimbutas, due to the lasting practice of burying the dead under mounds (“kurgan”) among the succession of cultures in that region. It is now known that kurgan-type burials only date from the 4th millennium BCE and almost certainly originated south of the Caucasus. The genetic diversity of R1b being greater around eastern Anatolia, it is hard to deny that R1b evolved there before entering the steppe world.
Horses were first domesticated around 4600 BCE in the Caspian Steppe, perhaps somewhere around the Don or the lower Volga, and soon became a defining element of steppe culture. Nevertheless it is unlikely that R1b was already present in the eastern steppes at the time, so the domestication of the horse should be attributed to the indigenous R1a people, or tribes belonging to the older R1b-P297 branch, which settled in eastern Europe during the Late Paleolithic or Mesolithic period. Samples from Mesolithic Samara (Haak 2015) and Latvia (Jones 2017) all belonged to R1b-P297. Autosomally these Mesolithic R1a and R1b individuals were nearly pure Mesolithic East European, sometimes with a bit of Siberian admixture, but lacked the additional Caucasian admixture found in the Chalcolithic Afanasevo, Yamna and Corded Ware samples.
It is not yet entirely clear when R1b-M269 crossed over from the South Caucasus to the Pontic-Caspian steppe. This might have happened with the appearance of the Dnieper-Donets culture (c. 5100-4300 BCE). This was the first truly Neolithic society in the Pontic-Caspian Steppe. Domesticated animals (cattle, sheep and goats) were herded throughout the steppes and funeral rituals were elaborate. Sheep wool would play an important role in Indo-European society, notably in the Celtic and Germanic (R1b branches of the Indo-Europeans) clothing traditions up to this day. However, many elements indicate a continuity in the Dnieper-Donets culture with the previous Mesolithic hunter-gatherers, and at the same time an influence from the Balkans and Carpathians, with regular imports of pottery and copper objects. It is therefore more likely that Dnieper-Donets marked the transition of indigenous R1a and/or I2a1b people to early agriculture, perhaps with an influx of Near Eastern farmers from ‘Old Europe’. Over 30 DNA samples from Neolithic Ukraine (5500-4800 BCE) were tested by Mathieson et al. (2017). They belonged to Y-haplogroups I, I2a2, R1a, R1b1a (L754) and one R1b1a2 (L388). None of them belonged to R1b-M269 or R1b-L23 clades, which dominated during the Yamna period. Mitochondrial lineages were also exclusively of Mesolithic European origin (U4a, U4b, U4d, U5a1, U5a2, U5b2, as well as one J2b1 and one U2e1). None of those maternal lineages include typical Indo-European haplogroups, like H2a1, H6, H8, H15, I1a1, J1b1a, W3, W4 or W5 that would later show up in the Yamna, Corded Ware and Unetice cultures. Indeed, autosomally genomes from Neolithic Ukraine were purely Mesolithic European (about 90% EHG and 10% WHG) and completely lacked the Caucasian (CHG) admixture later found in Yamna and subsequent Indo-European cultures during the Bronze Age.
The first clearly Proto-Indo-European cultures were the Khvalynsk (5200-4500 BCE) and Sredny Stog (4600-3900 BCE) cultures in the Pontic-Caspian Steppe. This is when small kurgan burials begin to appear, with the distinctive posturing of the dead on the back with knees raised and oriented toward the northeast, which would be found in later steppe cultures as well. There is evidence of population blending from the variety of skull shapes. Towards the end of the 5th millennium, an elite starts to develop with cattle, horses and copper used as status symbols. It is at the turn of the Khvalynsk and Sredny Stog periods that R1b-M269’s main subclade, L23, is thought to have appeared, around 4,500 BCE. 99% of Indo-European R1b descends from this L23 clade. The other branch descended from M269 is PF7562, which is found mostly in the Balkans, Turkey and Armenia today, and may represent an early Steppe migration to the Balkans dating from the Sredny Stog period.
Another migration across the Caucasus happened shortly before 3700 BCE, when the Maykop culture, the world’s first Bronze Age society, suddenly materialized in the north-west Caucasus, apparently out of nowhere. The origins of Maykop are still uncertain, but archeologists have linked it to contemporary Chalcolithic cultures in Assyria and western Iran. Archeology also shows a clear diffusion of bronze working and kurgan-type burials from the Maykop culture to the Pontic Steppe, where the Yamna culture developed soon afterwards (from 3500 BCE). Kurgan (a.k.a. tumulus) burials would become a dominant feature of ancient Indo-European societies and were widely used by the Celts, Romans, Germanic tribes, and Scythians, among others.
The Yamna period (3500-2500 BCE) is the most important one in the creation of Indo-European culture and society. Middle Eastern R1b-M269 people had been living and blending to some extent with the local R1a foragers and herders for over a millennium, perhaps even two or three. The close cultural contact and interactions between R1a and R1b people all over the Pontic-Caspian Steppe resulted in the creation of a common vernacular, a new lingua franca, which linguists have called Proto-Indo-European (PIE). It is pointless to try to assign another region of origin to the PIE language. Linguistic similarities exist between PIE and Caucasian and Hurrian languages in the Middle East on the one hand, and Uralic languages in the Volga-Ural region on the other hand, which makes the Pontic Steppe the perfect intermediary region.
During the Yamna period cattle and sheep herders adopted wagons to transport their food and tents, which allowed them to move deeper into the steppe, giving rise to a new mobile lifestyle that would eventually lead to the great Indo-European migrations. This type of mass migration in which whole tribes moved with the help of wagons was still common in Gaul at the time of Julius Caesar, and among Germanic peoples in the late Antiquity.
The Yamna horizon was not a single, unified culture. In the south, along the northern shores of the Black Sea coast until the north-west Caucasus, was a region of open steppe, expanding eastward until the Caspian Sea, Siberia and Mongolia (the Eurasian Steppe). The western section, between the Don and Dniester Rivers (and later the Danube), was the one most densely settled by R1b people, with only a minority of R1a people (5-10%). The eastern section, in the Volga basin until the Ural Mountains, was inhabited by R1a people with a substantial minority of R1b people (whose descendants can be found among the Bashkirs, Turkmans, Uyghurs and Hazaras, among others). The northern part of the Yamna horizon was forest-steppe occupied by R1a people, also joined by a small minority of R1b (judging from Corded Ware samples and from modern Russians and Belarussians, whose frequency of R1b is from seven to nine times lower than R1a). The western branch would migrate to the Balkans and Greece, then to Central and Western Europe, and back to their ancestral Anatolia in successive waves (Hittites, Phrygians, Armenians, etc.). The eastern branch would migrate to Central Asia, Xinjiang, Siberia, and South Asia (Iran, Pakistan, India). The northern branch would evolve into the Corded Ware culture and disperse around the Baltic, Poland, Germany and Scandinavia.
The Maykop culture, the R1b link to the Steppe?
The Maykop culture (3700-2500 BCE) in the north-west Caucasus was culturally speaking a sort of southern extension of the Yamna horizon. Although not generally considered part of the Pontic-Caspian steppe culture due to its geography, the North Caucasus had close links with the steppes, as attested by numerous ceramics, gold, copper and bronze weapons and jewelry in the contemporaneous cultures of Mikhaylovka, Sredny Stog and Kemi Oba. The link between the northern Black Sea coast and the North Caucasus is older than the Maykop period. Its predecessor, the Svobodnoe culture (4400-3700 BCE), already had links to the Suvorovo-Novodanilovka and early Sredny Stog cultures. The even older Nalchik settlement (5000-4500 BCE) in the North Caucasus displayed a similar culture as Khvalynsk in the Caspian Steppe and Volga region. This may be the period when R1b started interacting and blending with the R1a population of the steppes.
The Yamna and Maykop people both used kurgan burials, placing their dead in a supine position with raised knees and oriented in a north-east/south-west axis. Graves were sprinkled with red ochre on the floor, and sacrificed domestic animal buried alongside humans. They also had in common horses, wagons, a heavily cattle-based economy with a minority of sheep kept for their wool, use of copper/bronze battle-axes (both hammer-axes and sleeved axes) and tanged daggers. In fact, the oldest wagons and bronze artefacts are found in the North Caucasus and appear to have spread from there to the steppes.
Maykop was an advanced Bronze Age culture, actually one of the very first to develop metalworking, and therefore metal weapons. The world’s oldest sword was found at a late Maykop grave in Klady kurgan 31. Its style is reminiscent of the long Celtic swords, though less elaborated. Horse bones and depictions of horses already appear in early Maykop graves, suggesting that the Maykop culture might have been founded by steppe people or by people who had close link with them. However, the presence of cultural elements radically different from the steppe culture in some sites could mean that Maykop had a hybrid population. Without DNA testing it is impossible to say if these two populations were an Anatolian R1b group and a G2a Caucasian group, or whether R1a people had settled there too. The two or three ethnicities might even have cohabited side by side in different settlements. The one typical Caucasian Y-DNA lineage that does follow the pattern of Indo-European migrations is G2a-L13, which is found throughout Europe, Central Asia and South Asia. In the Balkans, the Danube basin and Central Europe its frequency is somewhat proportional to the percentage of R1b.
Maykop people are the ones credited for the introduction of primitive wheeled vehicles (wagons) from Mesopotamia to the Steppe. This would revolutionize the way of life in the steppe and would later lead to the development of (horse-drawn) war chariots around 2000 BCE. Cavalry and chariots played a vital role in the subsequent Indo-European migrations, allowing them to move quickly and defeat easily anybody they encountered. Combined with advanced bronze weapons and their sea-based culture, the western branch (R1b) of the Indo-Europeans from the Black Sea shores are excellent candidates for being the mysterious Sea Peoples, who raided the eastern shores of the Mediterranean during the second millennium BCE.
The rise of the IE-speaking Hittites in Central Anatolia happened a few centuries after the disappearance of the Maykop and Yamna cultures. Considering that most Indo-European forms of R1b found in Anatolia today belong to the R1b-Z2103 subclade, it makes little doubt that the Hittites came to Anatolia via the Balkans, after Yamna/Maykop people invaded Southeast Europe. The Maykop and Yamna cultures were succeeded by the Srubna culture (1600-1200 BCE), possibly representing an advance of R1a-Z282 people from the northern steppes towards the Black Sea shores, filling the vacuum left by the R1b tribes who migrated to Southeast Europe and Anatolia.
The Siberian & Central Asian branch
When R1b crossed the Caucasus in the Late Neolithic, it split into two main groups. The western one (L51) would settle the eastern and northern of the Black Sea. The eastern one (Z2103) migrated to the Don-Volga region, where horses were domesticated circa 4600 BCE. R1b probably mixed with indigenous R1a people and founded the Repin culture (3700-3300 BCE) a bit before the Yamna culture came into existence in the western Pontic Steppe. R1b would then have migrated with horses along the Great Eurasian Steppe until the Altai mountains in East-Central Asia, where they established the Afanasevo culture (c. 3600-2400 BCE). Afanasevo people might be the precursors of the Tocharian branch of Indo-European languages. In 2014, Clément Hollard of Strasbourg University tested three Y-DNA samples from the Afanasevo culture and all three turned out to belong to haplogroup R1b, including two to R1b-M269.
The R1b people who stayed in the Volga-Ural region were probably the initiators of the Poltavka culture (2700-2100 BCE), then became integrated into the R1a-dominant Sintashta-Petrovka culture (2100-1750 BCE) linked to the Indo-Aryan conquest of Central and South Asia (=> see R1a for more details).
Nowadays in Russia R1b is found at higher frequencies among ethnic minorities of the Volga-Ural region (Udmurts, Komi, Mordvins, Tatars) than among Slavic Russians. R1b is also present in many Central Asian populations, the highest percentages being observed among the Uyghurs (20%) of Xinjiang in north-west China, the Yaghnobi people of Tajikistan (32%), and the Bashkirs (47%, or 62.5% in the Abzelilovsky district) of Bashkortostan in Russia (border of Kazakhstan).
R1b-M73, found primarily in North Asia (Altai, Mongolia), Central Asia and the North Caucasus is thought to have spread during the Neolithic from the Middle East to Central and North Asia, and therefore can be considered to be pre-Indo-European.
The European & Middle Eastern branch
The Indo-Europeans’ bronze weapons and the extra mobility provided by horses would have given them a tremendous advantage over the autochthonous inhabitants of Europe, namely the native haplogroup C1a2, F and I (descendants of Cro-Magnon) and the early Neolithic herders and farmers (G2a, H2, E1b1b and T1a). This allowed R1a and R1b to replace most of the native male lineages (=> see How did R1b come to replace most of the older lineages in Western Europe?), although female lineages seem to have been less affected.
A comparison with the Indo-Iranian invasion of South Asia shows that 40% of the male linages of northern India are R1a, but less than 10% of the female lineages could be of Indo-European origin. The impact of the Indo-Europeans was more severe in Europe because European society 4,000 years ago was less developed in terms of agriculture, technology (no bronze weapons) and population density than that of the Indus Valley civilization. This is particularly true of the native Western European cultures where farming arrived much later than in the Balkans or Central Europe. Greece, the Balkans and the Carpathians were the most advanced of European societies at the time and were the least affected in terms of haplogroup replacement. Neolithic lineages survived better in regions that were more difficult to reach or less hospitable to horse breeders, like the Alps, the Dinaric Alps, the Apennines and Sardinia.
The Conquest of “Old Europe” and Central Europe (4200-2500 BCE)
The first forays of Steppe people into the Balkans happened between 4200 BCE and 3900 BCE, when cattle herders equipped with horse-drawn wagons crossed the Dniester and Danube and apparently destroyed the towns of the Gumelnița, Varna and Karanovo VI cultures in Eastern Romania and Bulgaria. A climatic change resulting in colder winters during this exact period probably pushed steppe herders to seek milder pastures for their stock, while failed crops would have led to famine and internal disturbance within the Danubian and Balkanic communities. The ensuing Cernavodă culture (Copper Age, 4000-3200 BCE), Coțofeni/Usatovo culture (Copper to Bronze Age, 3500-2500 BCE), Ezero culture (Bronze Age, 3300-2700 BCE), in modern Romania, seems to have had a mixed population of steppe immigrants and people from the old tell settlements. These Steppe immigrants were likely a mixture of both R1a and R1b lineages, with a probably higher percentage of R1a than later Yamna-era invasions.
The Steppe invaders would have forced many Danubian farmers to migrate to the Cucuteni-Trypillian towns in the eastern Carpathians, causing a population boom and a north-eastward expansion until the Dnieper valley, bringing Y-haplogroups G2a, I2a1 (probably the dominant lineage of the Cucuteni-Trypillian culture), E1b1b, J2a and T1a in what is now central Ukraine. This precocious Indo-European advance westward was fairly limited, due to the absence of Bronze weapons and organized army at the time and was indeed only possible thanks to climatic catastrophes which reduced the defenses of the towns of Old Europe. The Carphatian, Danubian, and Balkanic cultures were too densely populated and technologically advanced to allow for a massive migration.
In comparison the forest-steppe R1a people successfully penetrated into the heart of Europe with little hindrance, due to the absence of developed agrarian societies around Poland and the Baltic. The Corded Ware culture (3200-1800 BCE) was a natural northern and western expansion of the Yamna culture, reaching as far west as Germany and as far north as Sweden and Norway. DNA analysis from the Corded Ware confirmed the presence of R1a and R1b in Poland c. 2700 BCE and R1a central Germany around 2600 BCE. The Corded Ware tribes expanded from the northern fringe of the Yamna culture where R1a lineages were prevalent over R1b ones.
The expansion of R1b people into Old Europe was slower, but proved inevitable. In 2800 BCE, by the time the Corded Ware had already reached Scandinavia, the Bronze Age R1b cultures had barely moved into the Pannonian Steppe. They established major settlements in the Great Hungarian Plain, the most similar habitat to their ancestral Pontic Steppes. Around 2500 BCE, the western branch of Indo-European R1b were poised for their next major expansion into modern Germany and Western Europe. By that time, the R1b immigrants had blended to a great extent with the indigenous Mesolithic and Neolithic populations of the Danubian basin, where they had now lived for 1,700 years.
The strongly patriarchal Indo-European elite remained almost exclusively R1b on the paternal side, but absorbed a high proportion of non-Indo-European maternal lineages. Hybridized, the new Proto-Indo-European R1b people would have lost most of their remaining Proto-Europoid or Mongolid features inherited from their Caspian origins (which were still clearly visible in numerous individuals from the Yamna period). Their light hair, eye and skin pigmentation, once interbred with the darker inhabitants of Old Europe, became more like that of modern Southern Europeans. The R1a people of the Corded Ware culture would come across far less populous societies in Northern Europe, mostly descended from the lighter Mesolithic population, and therefore retained more of their original pigmentation (although facial traits evolved considerably in Scandinavia, where the I1 inhabitants were strongly dolicocephalic and long-faced, as opposed to the brachycephalic and broad-faced Steppe people).
The Conquest of Western Europe (2500-1200 BCE)
The R1b conquest of Europe happened in two phases. For nearly two millennia, starting from circa 4200 BCE, Steppe people limited their conquest to the rich Chalcolithic civilizations of the Carpathians and the Balkans. These societies possessed the world’s largest towns, notably the tell settlements of the Cucuteni-Tripolye culture. Nothing incited the R1b conquerors to move further into Western Europe at such an early stage, because most of the land north and west of the Alps was still sparsely populated woodland. The Neolithic did not reach the British Isles and Scandinavia before circa 4000 BCE. Even northern France and most of the Alpine region had been farming or herding for less than a millennium and were still quite primitive compared to Southeast Europe and the Middle East.
North-west Europe remained a tribal society of hunter-gatherers practicing only limited agriculture for centuries after the conquest of the Balkans by the Indo-Europeans. Why would our R1b “conquistadors” leave the comfort of the wealthy and populous Danubian civilizations for the harsh living conditions that lie beyond? Bronze Age people coveted tin, copper, and gold, of which the Balkans had plenty, but that no one had yet discovered in Western Europe.
R1b-L51 is thought to have arrived in Central Europe (Hungary, Austria, Bohemia) around 2500 BCE, approximately two millennia after the shift to the Neolithic lifestyle in these regions. Agrarian towns had started to develop. Gold and copper had begun to be mined. The prospects of a conquest were now far more appealing.
The archeological and genetic evidence (distribution of R1b subclades) point at several consecutive waves towards eastern and central Germany between 2800 BCE and 2300 BCE. The Unetice culture was probably the first culture in which R1b-L11 lineages played a major role. It is interesting to note that the Unetice period happen to correspond to the end of the Maykop (2500 BCE) and Kemi Oba (2200 BCE) cultures on the northern shores of the Black Sea, and their replacement by cultures descended from the northern steppes. It can therefore be envisaged that the (mostly) R1b population from the northern half of the Black Sea migrated westward due to pressure from other Indo-European people (R1a) from the north, for example that of the burgeoning Proto-Indo-Iranian branch, linked to the contemporary Poltavka and Abashevo cultures.
It is doubtful that the Bell Beaker culture (2800-1900 BCE) in Western Europe was already Indo-European because its attributes are in perfect continuity with the native Megalithic cultures. The Beaker phenomenon started during the Late Neolithic and Early Chalcolithic in Portugal and propagated to the north-east towards Germany. During the same period Bronze Age Steppe cultures spread from Germany in the opposite direction towards Iberia, France and Britain, progressively bringing R1b lineages into the Bell Beaker territory. It is more likely that the beakers and horses found across Western Europe during that period were the result of trade with neighboring Indo-European cultures, including the first wave of R1b into Central Europe. It is equally possible that the Beaker people were R1b merchants or explorers who travelled across Western Europe and brought back tales of riches poorly defended by Stone Age people waiting to be to be conquered. This would have prompted a full-scale Indo-European (R1b) invasion from about 2500 BCE in Germany, reaching the Atlantic (north of the Pyrenees at least) around 2200 BCE.
Ancient DNA tests conducted by Lee et al. (2012), Haak et al. (2015) and Allentoft et al. (2015) have all confirmed the presence of R1b-L51 (and deeper subclades such as P312 and U152) in Germany from the Bell Beaker period onwards, but none in earlier cultures. German Bell Beaker R1b samples only had about 50% of Yamna autosomal DNA and often possessed Neolithic non-Steppe mtDNA, which confirms that R1b invaders took local wives as they advanced westward. Another study by Olalde et al. (2017) confirmed that Iberian Bell Beakers were genetically distinct from the previously tested German samples. None of the Spanish or Portuguese individuals associated with Bell Beaker pottery possessed any Steppe admixture, and none belonged to the Indo-European haplogroup R1b-L23 or its subclades. Instead they belonged to typical Megalithic lineages like G2a, I2a1, I2a2 and the Neolithic R1b-V88. The paper also confirmed a high frequency of R1b-L51 lineages in central Europe during the Beall Beaker period. In Britain, Megalithic individuals belonged exclusively to Y-haplogroup I2 (mostly I2a2 and I2a1b-L161) but were entirely replaced by R1b-L51 (mostly L21 clade) in the Early Bronze Age. This means that the Bell Beaker culture was not associated with one particular ethnic group. Beaker pottery originated in Megalithic Iberia, but then spread to France and central Europe and was used by invading R1b-L51 Steppe people, who brought it with them to the British Isles, while wiping out most of the indigenous Megalithic population. There was therefore no ‘Bell Beaker people’, but just various populations trading and using Beaker pots during that period.
DNA samples from the Unetice culture (2300-1600 BCE) in Germany, which emerged less than two centuries after the appearance of the first R1b-L51 individuals in the late Bell Beaker Germany, had a slightly higher percentage of Yamna ancestry (60~65%) and of Yamna-related mtDNA lineages, which indicates a migration of both Steppe men and women. That would explain why archeological artefacts from the Unetice culture are clearly Yamna-related (i.e. Indo-European), as they abruptly introduced new technologies and a radically different lifestyle, while the Bell Beaker culture was in direct continuity with previous Neolithic or Chalcolithic cultures. R1b men may simply have conquered the Bell Beaker people and overthrown the local rulers without obliterating the old culture due to their limited numbers. Taking the analogy of the Germanic migrations in the Late Antiquity, the R1b invasion of the Bell Beaker period was more alike to that of the Goths, Burgunds and Vandals, who all migrated in small numbers, created new kingdoms within the Roman empire, but adopted Latin language and Roman culture. In contrast, the Corded Ware and Unetice culture involved large-scale migrations of Steppe people, who imposed their Indo-European language and culture and conquered people, just like the Anglo-Saxons or the Bavarians did in the 5th century.
The Atlantic Celtic branch (L21)
The Proto-Italo-Celto-Germanic R1b people had reached in what is now Germany by 2500 BCE. By 2300 BCE they had arrived in large numbers and founded the Unetice culture. Judging from the propagation of bronze working to Western Europe, those first Indo-Europeans reached France and the Low Countries by 2200 BCE, Britain by 2100 BCE and Ireland by 2000 BCE, and Iberia by 1800 BCE. This first wave of R1b presumably carried R1b-L21 lineages in great number (perhaps because of a founder effect), as these are found everywhere in western, northern and Central Europe. Cassidy et al. (2015) confirmed the presence of R1b-L21 (DF13 and DF21 subclades) in Ireland around 2000 BCE. Those genomes closely resembled those of the Unetice culture autosomally, but differed greatly from the earlier Neolithic Irish samples. This confirms that a direct migration of R1b-L21 from Central Europe was responsible for the introduction of the Bronze Age to Ireland.
The early split of L21 from the main Proto-Celtic branch around Germany would explain why the Q-Celtic languages (Goidelic and Hispano-Celtic) diverged so much from the P-Celtic branch (La Tène, Gaulish, Brythonic), which appears to have expanded from the later Urnfield and Hallstat cultures.
Some L21 lineages from the Netherlands and northern Germany later entered Scandinavia (from 1700 BCE) with the dominant subclade of the region, R1b-S21/U106 (see below). The stronger presence of L21 in Norway and Iceland can be attributed to the Norwegian Vikings, who had colonized parts of Scotland and Ireland and taken slaves among the native Celtic populations, whom they brought to their new colony of Iceland and back to Norway. Nowadays about 20% of all Icelandic male lineages are R1b-L21 of Scottish or Irish origin.
In France, R1b-L21 is mainly present in historical Brittany (including Mayenne and Vendée) and in Lower Normandy. This region was repopulated by massive immigration of insular Britons in the 5th century due to pressure from the invading Anglo-Saxons. However, it is possible that L21 was present in Armorica since the Bronze age or the Iron age given that the tribes of the Armorican Confederation of ancient Gaul already had a distinct identity from the other Gauls and had maintained close ties with the British Isles at least since the Atlantic Bronze Age.
The Gallic & Iberian branch (DF27/S250)
The first Proto-Celtic R1b lineages to reach France and the Iberian Peninsula from Central Europe were probably L21 and DF27. Whereas L21 might have taken a northern route through Belgium and northern France on its way to the British Isles, DF27 seems to have spread all over France but heading in greater number toward the south.
The Bronze Age did not appear in Iberia until 1800 BCE, and was mostly confined to the cultures of El Argar and Los Millares in south-east Spain, with sporadic sites showing up in Castile by 1700 BCE and in Extremadura and southern Portugal by 1500 BCE. These Early Bronze Age sites typically did not have more than some bronze daggers or axes and cannot be considered proper Bronze Age societies, but rather Copper Age societies with occasional bronze artefacts (perhaps imported). These cultures might have been founded by small groups of R1b adventurers looking for easy conquests in parts of Europe that did not yet have bronze weapons. They would have become a small ruling elite, would have had children with local women, and within a few generations their Indo-European language would have been lost, absorbed by the indigenous languages (=> see How did the Basques become R1b?).
Martiniano et al. (2017) sequenced the genomes of various skeletons from West Iberia dating from the Middle and Late Neolithic, Chalcolithic and Middle Bronze Age (since the Early Bronze Age did not reach that region). They found that Neolithic and Chalcolithic individuals belonged to Y-haplogroups I*, I2a1 and G2a. In contrast, all three Bronze Age Portuguese men tested belonged to R1b (one M269 and two P312), although they carried Neolithic Iberian maternal lineages (H1, U5b3, X2b) and lacked any discernible Steppe admixture. This is concordant with a scenario of Indo-European R1b men entering Iberia from 1800 BCE as a small group of adventurers and taking local wives, thus diluting their DNA at each generation, until hardly any Steppe admixture was left after a few centuries, by the time they reached Portugal. Nowadays, Spaniards and Portuguese do possess about 25% of Steppe admixture, which means that other more important Indo-European migrations took place later on, during the Late Bronze Age and the Iron Age.
Iberia did not become a fully-fledged Bronze Age society until the 13th century BCE, when the Urnfield culture (1300-1200 BCE) expanded from Germany to Catalonia via southern France, then the ensuing Hallstatt culture (1200-750 BCE) spread throughout most of the peninsula (especially the western half). This period belongs to the wider Atlantic Bronze Age (1300-700 BCE), when Iberia was connected to the rest of Western Europe through a complex trade network.
It is hard to say when exactly DF27 entered Iberia. Considering its overwhelming presence in the peninsula and in south-west France, it is likely that DF27 arrived early, during the 1800 to 1300 BCE period, and perhaps even earlier, if R1b adventurers penetrated the Bell Beaker culture, as they appear to have done all over Western Europe from 2300 BCE to 1800 BCE. The Atlantic Bronze Age could correspond to the period when DF27 radiated more evenly around Iberia and ended up, following Atlantic trade routes, all the way to the British Isles, the Netherlands and Scandinavia.
The Italo-Celtic branch (S28/U152/PF6570)
Starting circa 1300 BCE, a new Bronze Age culture flourished around the Alps thanks to the abundance of metal in the region and laid the foundation for the classical Celtic culture. It was actually the succession of three closely linked culture: the Urnfield culture, which would evolve into the Hallstatt culture (from 1200 BCE) and eventually into the La Tène culture (from 450 BCE). After the Unetice expansion to Western Europe between 2300 and 1800 BCE, the Urnfield/Hallstatt/La Tène period represents the second major R1b expansion that took place from Central Europe, pushing west to the Atlantic, north to Scandinavia, east to the Danubian valley, and eventually as far away as Greece, Anatolia, Ukraine and Russia, perhaps even until the Tarim basin in north-west China (=> see Tarim mummies.
The Celtic Iron Age (late Halstatt, from 800 BCE) may have been brought through preserved contacts with the steppes and the North Caucasus, notably the Koban culture (1100-400 BCE).
The Alpine Celts of the Hallstatt culture are associated with the S28 (a.k.a. U152 or PF6570) mutation, although not exclusively. R1b-S28 would have entered Italy in successive waves from the northern side of the Alps, starting in 1700 BCE with the establishment of the Terramare culture in the Po Valley. From 1200 BCE, a larger group of Hallstatt-derived tribes founded the Villanova culture (see below). This is probably the migration that brought the Italic-speaking tribes to Italy, who would have belonged mainly the Z56 clade of R11b-S28. During the Iron Age, the expansion of the La Tène culture from Switzerland is associated with the diffusion of the Z36 branch, which would generate the Belgae around modern Belgium and in the Rhineland, the Gauls in France, and the Cisalpine Celts in Italy.
One common linguistic trait between Italic and Gaulish/Brythonic Celtic languages linked to the Hallstatt expansion is that they shifted the original IE *kw sound into *p. They are known to linguists as the P-Celtic branch (as opposed to Q-Celtic). It is thought that this change occurred due to the inability to pronounce the *kw sound by the pre-Indo-European population of Central Europe, Gaul and Italy, who were speakers of Afro-Asiatic dialects that had evolved from Near-Eastern languages inherited from the Neolithic. The Etruscans, although later incomers from the eastern Mediterranean, also fit in this category. It has recently been acknowledged that Celtic languages borrowed part of their grammar from Afro-Asiatic languages. This shift could have happened when the Proto-Italo-Celtic speakers moved from the steppes to the Danube basin and mixed with the population of Near-Eastern farmers belonging to haplogroups E1b1b, G2a, J and T. However, such an early shift would not explain why Q-Celtic and Germanic languages did not undergo the same linguistic mutation. It is therefore more plausible that the shift happened after the Proto-Italo-Celts and Proto-Germanics had first expanded across all western and northern Europe. The S28/U152 connection to P-Celtic (and Italic) suggests that the shift took place around the Alps after 1800 BCE, but before the invasion of Italy by the Italic tribes circa 1200 BCE.
The expansion of the Urnfield/Hallstatt culture to Italy is evident in the form of the Villanovan culture (c. 1100-700 BCE), which shared striking resemblances with the Urnfield/Hallstatt sites of Bavaria and Upper Austria. The Villanova culture marks a clean break with the previous Terramare culture. Although both cultures practiced cremation, whereas Terramare people placed cremated remains in communal ossuaries like their Neolithic ancestors from the Near East, Villanovans used distinctive Urnfield-style double-cone shaped funerary urns, and elite graves containing jewelry, bronze armor and horse harness fittings were separated from ordinary graves, showing for the first time the development of a highly hierarchical society, so characteristic of Indo-European cultures. Quintessential Indo-European decorations, such as swastikas, also make their appearance. Originally a Bronze-age culture, the Villanova culture introduced iron working to the Italian peninsula around the same time as it appeared in the Hallstatt culture, further reinforcing the link between the two cultures. In all likelihood, the propagation of the Villanova culture represents the Italic colonization of the Italian peninsula. The highest proportion of R1b-S28 is found precisely where the Villanovans were the more strongly established, around modern Tuscany and Emilia-Romagna. The Villanova culture was succeeded by the Etruscan civilization, which displayed both signs of continuity with Villanova and new hybrid elements of West Asian origins, probably brought by Anatolian settlers (who would have belonged to a blend of haplogroups E1b1b, G2a, J1, J2 and R1b-L23).
The Germanic branch (S21/U106/M405)
The principal Proto-Germanic branch of the Indo-European family tree is R1b-S21 (a.k.a. U106 or M405). This haplogroup is found at high concentrations in the Netherlands and north-west Germany. It is likely that R1b-S21 lineages expanded in this region through a founder effect during the Unetice period, then penetrated into Scandinavia around 1700 BCE (probably alongside R1a-L664), thus creating a new culture, that of the Nordic Bronze Age (1700-500 BCE). R1b-S21 would then have blended for more than a millennium with preexisting Scandinavian populations, represented by haplogroups I1, I2-L801, R1a-Z284. When the Germanic Iron Age started c. 500 BCE, the Scandinavian population had developed a truly Germanic culture and language but was divided in many tribes with varying levels of each haplogroup. R1b-S21 became the dominant haplogroup among the West Germanic tribes, but remained in the minority against I1 and R1a in East Germanic and Nordic tribes, including those originating from Sweden such as the Goths, the Vandals and Lombards.
The presence of R1b-S21 in other parts of Europe can be attributed almost exclusively to the Germanic migrations that took place between the 3rd and the 10th century. The Frisians and Anglo-Saxons disseminated this haplogroup to England and the Scottish Lowlands, the Franks to Belgium and France, the Burgundians to eastern France, the Suebi to Galicia and northern Portugal, and the Lombards to Austria and Italy. The Goths help propagate S21 around Eastern Europe, but apparently their Germanic lineages were progressively diluted by blending with Slavic and Balkanic populations, and their impact in Italy, France and Spain was very minor. Later the Danish and Norwegian Vikings have also contributed to the diffusion of R1b-S21 (alongside I1, I2b1 and R1a) around much of Western Europe, but mainly in Iceland, in the British Isles, in Normandy, and in the southern Italy.
From the Late Middle Ages until the early 20th century, the Germans expanded across much of modern Poland, pushing as far as Latvia to the north-east and Romania to the south-east. During the same period the Austrians built an empire comprising what is now the Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Serbia, and parts of Romania, western Ukraine and southern Poland. Many centuries of German and Austrian influence in central and Eastern Europe resulted in a small percentage of Germanic lineages being found among modern populations. In Romania 4% of the population still consider themselves German. The low percentage of R1b-S21 in Finland, Estonia and Latvia can be attributed to the Swedish or Danish rule from the late Middle Ages to the late 19th century.
How did R1b come to replace most of the older lineages in Western Europe?
Until recently it was believed that R1b originated in Western Europe due to its strong presence in the region today. The theory was that R1b represented the Paleolithic Europeans (Cro-Magnon) that had sought refuge in the Franco-Cantabrian region at the peak of the last Ice Age, then recolonized Central and Northern Europe once the ice sheet receded. The phylogeny of R1b proved that this scenario was not possible, because older R1b clades were consistently found in Central Asia and the Middle East, and the youngest in Western and Northern Europe. There was a clear gradient from East to West tracing the migration of R1b people (see map above). This age of the main migration from the shores of the Black Sea to Central Europe also happened to match the timeframe of the Indo-European invasion of Europe, which coincides with the introduction of the Bronze-Age culture in Western Europe, and the proliferation of Italo-Celtic and Germanic languages.
Historians and archeologists have long argued whether the Indo-European migration was a massive invasion, or rather a cultural diffusion of language and technology spread only by a small number of incomers. The answer could well be “neither”. Proponents of the diffusion theory would have us think that R1b is native to Western Europe, and R1a alone represent the Indo-Europeans. The problem is that haplogroup R did arise in Central Asia, and R2 is still restricted to Central and South Asia, while R1a and the older subclades of R1b are also found in Central Asia. The age of R1b subclades in Europe coincide with the Bronze-Age. R1b must consequently have replaced most of the native Y-DNA lineages in Europe from the Bronze-Age onwards.
However, a massive migration and nearly complete annihilation of the Paleolithic population can hardly be envisaged. Western Europeans do look quite different in Ireland, Holland, Aquitaine or Portugal, despite being all regions where R1b is dominant. Autosomal DNA studies have confirmed that the Western European population is far from homogeneous. A lot of maternal lineages (mtDNA) also appear to be of Paleolithic origin (e.g. H1, H3, U5 or V) based on ancient DNA tests. What a lot of people forget is that there is also no need of a large-scale exodus for patrilineal lineages to be replaced fairly quickly. Here is why.
- Polygamy. Unlike women, men are not limited in the number of children they can procreate. Men with power typically have more children. This was all the truer in primitive societies, where polygamy was often the norm for chieftains and kings.
- Status & Power. Equipped with Bronze weapons and horses, the Indo-Europeans would have easily subjugated the Neolithic farmers and with even greater ease Europe’s last hunter-gatherers. If they did not exterminate the indigenous men, the newcomers would have become the new ruling class, with a multitude of local kings, chieftains and noblemen (Bronze-Age Celts and Germans lived in small village communities with a chief, each part of a small tribe headed by a king) with higher reproductive opportunities than average.
- Gender imbalance. Invading armies normally have far more men than women. Men must therefore find women in the conquered population. Wars are waged by men, and the losers suffer heavier casualties, leaving more women available to the winners.
- Aggressive warfare. The Indo-Europeans were a warlike people with a strong heroic code emphasizing courage and military prowess. Their superior technology (metal weapons, wheeled vehicles drawn by horses) and attitude to life would have allowed them to slaughter any population that did not have organized armies with metal weapons (i.e. anybody except the Middle-Eastern civilizations).
- Genetic predisposition to conceive boys. The main role of the Y-chromosome in man’s body is to create sperm. Haplogroups are determined based on mutations differentiating Y-chromosomes. Each mutation is liable to affect sperm production and sperm motility. Preliminary research has already established a link between certain haplogroups and increased or reduced sperm motility. The higher the motility, the higher the chances of conceiving a boy. It is absolutely possible that R1b could confer a bias toward more male offspring. Even a slightly higher percentage of male births would significantly contribute to the replacement of other lineages with the accumulation effect building up over a few millennia. Not all R1b subclades might have this boy bias. The bias only exists in relation to other haplogroups found in a same population. It is very possible that the fairly recent R1b subclades of Western Europe had a significant advantage compared to the older haplogroups in that region, notably haplogroup I2 and E-V13. Read more
Replacement of patrilineal lineages following this model quickly becomes exponential. Imagine 100 Indo-European men conquering a tribe of 1000 indigenous Europeans (a ratio of 1:10). War casualties have resulted in a higher proportion of women in the conquered population. Let’s say that the surviving population is composed of 700 women and 300 men. Let’s suppose that the victorious Indo-European men end up having twice as many children reaching adulthood as the men of the vanquished tribe. There is a number of reasons for that. The winners would take more wives, or take concubines, or even rape women of the vanquished tribe. Their higher status would guarantee them greater wealth and therefore better nutrition for their offspring, increasing the chances of reaching adulthood and procreating themselves. An offspring ratio of 2 to 1 for men is actually a conservative estimate, as it is totally conceivable that Bronze-Age sensibilities would have resulted in killing most of the men on the losing side, and raping their women (as attested by the Old Testament). Even so, it would only take a few generations for the winning Y-DNA lineages to become the majority. For instance, if the first generation of Indo-Europeans had two surviving sons per man, against only one per indigenous man, the number of Indo-European paternal lineages would pass to 200 individuals at the second generation, 400 at the third, 800 at the fourth and 1600 at the fifth, and so on. During that time indigenous lineages would only stagnate at 300 individuals for each generation.
Based on such a scenario, the R1b lineages would have quickly overwhelmed the local lineages. Even if the Indo-European conquerors had only slightly more children than the local men, R1b lineages would become dominant within a few centuries. Celtic culture lasted for over 1000 years in Continental Europe before the Roman conquest putting an end to the privileges of the chieftains and nobility. This is more than enough time for R1b lineages to reach 50 to 80% of the population.
The present-day R1b frequency forms a gradient from the Atlantic fringe of Europe (highest percentage) to Central and Eastern Europe (lowest), the rises again in the Anatolian homeland. This is almost certainly because agriculture was better established in Eastern, then Central Europe, with higher densities of population, leaving R1b invaders more outnumbered than in the West. Besides, other Indo-Europeans of the Corded Ware culture (R1a) had already advanced from modern Russia and Ukraine as far west as Germany and Scandinavia. It would be difficult for R1b people to rival with their R1a cousins who shared similar technology and culture. The Pre-Celto-Germanic R1b would therefore have been forced to settled further west, first around the Alps, then overtaking the then sparsely populated Western Europe.