The Kurgan Fathers: Did Most European Men Descend from a Handful of Steppe Herders?

Hero image: AI generated illustration of Early Bronze Age herders with an ox wagon beside kurgan burial mounds on the Pontic steppe, about 3000 BC. It is not a reconstruction of any individual.

If you are a man of western European descent, there is a good chance that your father's father's father, followed back about two hundred generations, was buried with his knees drawn up under a mound of earth somewhere between the Rhine and the Danube, among people whose own ancestors had come from the grasslands north of the Black Sea.

This is not a figure of speech. In 2015, a team led by Mark Jobling at the University of Leicester sequenced the Y chromosomes of 334 men from 17 populations of Europe and the Middle East. Three branches of the paternal family tree, R1b-M269, I1 and R1a, accounted for 64% of them, and all three were young: their common ancestors lived between roughly four and six thousand years ago. In most populations the authors also detected a sudden expansion of the male line starting between about 4,200 and 2,100 years ago. The university press release summed it up in one sentence: most European men descend from a handful of Bronze Age forefathers.

Ancient DNA has since turned that statistical hint into a historical event, with names, places and dates. The event begins with the people archaeologists call the Kurgan cultures, after the burial mounds (kurgan in Russian, from a Turkic word) that they raised over their dead.

A bottleneck written only in men

The first clue came from a strange pattern in modern genomes. When Monika Karmin and colleagues compared Y chromosomes and mitochondrial DNA from 456 men worldwide in 2015, they found that something happened to the male line, and only to the male line, after the spread of farming. Between about 8,000 and 4,000 years ago, the effective number of men contributing Y chromosomes to the next generation collapsed, in some regions to roughly one man for every seventeen women. Maternal lineages showed no such crash.

Fewer fathers does not mean fewer men. It means that a minority of men had most of the sons, and that their lineages kept winning generation after generation. In 2018, Tian Chen Zeng, Alan Aw and Marcus Feldman at Stanford showed with simulations that the pattern is best explained by competition between patrilineal clans: groups of men related through the male line who live together, fight together, and either expand or disappear as a block. When a clan is wiped out, its Y chromosome disappears with it. When a clan wins, its Y chromosome spreads, while women marrying in from outside keep the rest of the genome diverse.

Europe experienced this process in its most extreme form. And the clans that won were, overwhelmingly, the descendants of the steppe.

Who were the Kurgan people?

The Yamnaya were mobile herders of cattle and sheep who appeared on the Pontic and Caspian steppe around 3300 BC and within a few centuries spread from Hungary to Kazakhstan. They travelled with heavy wagons on solid wooden wheels, buried their dead lying on their backs with the knees raised, often sprinkled with red ochre, and covered the most important graves with earth mounds. Their genetic origins, in a mix of Caucasus to lower Volga and Dnipro hunter-gatherer ancestry, were worked out in 2025 and we covered them in detail in our article Where Did Indo-Europeans Really Come From?

This article follows what happened next, when their descendants entered the farming world of central and western Europe. The question is no longer where they came from, but who among them left descendants, and how many.

Three regions, one sudden break

To see the arrival as it happened, we modelled 871 dated ancient individuals from three well sampled regions, Britain, Iberia and Bohemia, as a mix of three sources: western hunter-gatherers (Loschbour, Luxembourg), Anatolian Neolithic farmers and the Samara Yamnaya. The share given to the Yamnaya is a simple measure of steppe ancestry.

The three panels tell three different stories. In Britain, not a single one of 125 Neolithic individuals carries steppe ancestry, and then, after about 2450 BC, every single person does, at 50 to 65%. There is no transition zone. In Bohemia, the first Corded Ware people around 2950 to 2850 BC are almost purely steppe in origin (92 to 98%), as if they had just arrived from the east, and their descendants slowly dilute toward 55 to 60% as they marry into local farming families. In Iberia, the change is far smaller and more scattered: a few newcomers with 20 to 45% from about 2400 BC, then a Bronze Age population in which steppe ancestry settles at 10 to 20%.

Before trusting the zeros, we tested them. We added known amounts of Yamnaya ancestry, 2, 3, 5 and 10%, to the average Neolithic profiles of each region and fitted them again. For Britain and Bohemia the method is sensitive: a 2% spike reads as 2.3% and 1.8% respectively, so the Neolithic zeros there are real to within about two percentage points. For Iberia it is not: spikes of up to 5% are invisible, and a 10% spike reads as only 4.0%. The Iberian Chalcolithic farmers carry more hunter-gatherer ancestry than the Anatolian source, and the solver absorbs a small steppe signal into it. The Iberian zeros should therefore be read as "less than about 8%", and the low Iberian Bronze Age values as minimums.

Britain: 90% of the gene pool in a few centuries

In 2018, Iñigo Olalde and a large international team published genomes from 400 individuals associated with the Bell Beaker phenomenon, a style of pottery and burial that spread across western Europe from about 2750 BC. They found that the Beaker people who reached Britain from the Lower Rhine around 2450 BC replaced about 90% of the island's gene pool within a few hundred years. The Y chromosome record was even starker. Haplogroup R1b was absent from 33 Neolithic British men. In the Copper and Bronze Age it accounted for more than 90% of 52 men.

Our Global25 models reproduce this closely. The British Beaker period population fits as 91.2% Dutch Bell Beaker and 8.8% British Neolithic, with a very low fit distance of 0.006. By the Middle Bronze Age the local share rises slightly, to 16.5%, which is a little more than the 10 ± 2% published by Olalde and colleagues. Patterson and colleagues documented a later influx from the continent, richer in farmer ancestry, during the Middle and Late Bronze Age, and part of it may already be visible here. One choice matters: with the German Bell Beakers as the source, the solver gives 100% incoming ancestry but fits worse (0.020 to 0.030), because the German Beakers carry more farmer ancestry than those who crossed to Britain.

A 90% genetic replacement is among the most dramatic population turnovers known from prehistory. Whether it was driven by violence, disease or simply by faster growth of the newcomers, the builders of Stonehenge left very few descendants in the male line.

Iberia: 40% of the genes, almost 100% of the fathers

Iberia is where the male bias is clearest, because the two numbers are so far apart. In 2019, Olalde and colleagues analysed 271 ancient Iberians and found that people with steppe ancestry arrived from about 2500 BC. At first they lived side by side with local groups that had none, and the two then mixed. By around 2000 BC, about 40% of Iberian ancestry had been replaced. But the Y chromosomes of the Copper Age, haplogroups I2, G2 and H, had been almost completely replaced by a single lineage, R1b-M269. The X chromosome, which spends two thirds of its time in women, showed less non local ancestry than the rest of the genome, pointing in the same direction: the newcomers who left descendants were mostly men.

One tomb captures the moment. At Castillejo del Bonete in La Mancha, the authors describe a man with steppe ancestry buried in the same tomb as a woman whose ancestry was similar to that of the Copper Age Iberians: two worlds meeting in a single grave.

Our models give 34% incoming ancestry for the Early Bronze Age and 49% for the later Bronze Age, bracketing the published 40%. They also pick out the first arrivals. Among the individuals labelled as Chalcolithic outliers with steppe ancestry, dated between about 2420 and 2130 BC, Yamnaya-related ancestry ranges from 19 to 35%, roughly half of what a central European Bell Beaker carries. They were not steppe nomads, but the descendants, several centuries removed, of people who had mixed with farmers all along the way from the Danube.

Today, Spanish Basques, who speak the only surviving pre-Indo-European language of western Europe, carry only about 26% Yamnaya-related ancestry in our model. Yet between 75 and 87% of Basque men carry R1b, one of the highest frequencies in the world. The language of the Copper Age survived. Its fathers did not.

Bohemia: the fathers were replaced twice

The most detailed record comes from Bohemia, in the modern Czech Republic. In 2021, Luka Papac, Wolfgang Haak and colleagues analysed 271 individuals from the third millennium BC, 206 of them new. What they found was not one replacement, but two, each lasting no more than a few generations.

The earliest Corded Ware men, from about 2900 BC, belonged to five different paternal lineages. The most common was R1b-L151, the direct ancestor of the R1b-P312 lineage that dominates western Europe today, carried by 6 of 11 men. Three carried R1a. Then, around 2600 BC, the diversity collapsed. In the late Corded Ware, 10 of 11 men carried one lineage, R1a-M417. The authors simulated how strong an advantage a lineage would need to rise this fast and estimated about 15.8% more surviving sons per generation (with a wide interval of 4 to 44%). Chance alone could not do it.

Two centuries later it happened again. The Bell Beaker men of Bohemia, from about 2400 BC, carry R1b-P312, and none of the late Corded Ware lineages: in the late Bell Beaker period, P312 reaches 100%. Then, at the start of the Unetice culture after 2200 BC, it falls to 20%, implying an influx of at least 80% new paternal lineages, including R1a-Z645, R1b-U106 and I2.

Our Global25 models show how little the rest of the genome moved in comparison. The early Corded Ware group is 81% Yamnaya-like, the late Corded Ware 74%. The Bell Beaker people, who carry more farmer ancestry, drop to 50%, and the Unetice population sits at 58%. The genome shifts by tens of percentage points. The Y chromosomes are replaced from 0 to 100% and back down again. Papac and colleagues also noticed that the four early Corded Ware individuals without any steppe ancestry were all women: local women were absorbed into the incoming communities, local men were not.

The fathers were not the Yamnaya themselves

Here the story takes a turn that rarely makes the headlines. The Yamnaya men sampled on the steppe belong overwhelmingly to R1b-M269, but to its eastern branch, R1b-Z2103, which is rare in western Europe today. The western European branch, R1b-L51 and its descendants P312 and U106, has not been found in a classic Yamnaya burial on the steppe. Nor has R1a-M417, the lineage that took over the late Corded Ware.

So the lineages that carry most western and northern European men today did not come from the Yamnaya men whose genomes we have. They came from closely related groups, probably on the western fringe of the Yamnaya world or in the forest steppe further north, whose genome-wide ancestry was nearly identical but whose paternal clans were different. In the language of Zeng and colleagues, Europe's present day fathers descend from the clans that won, and the Yamnaya of Samara were not among them. The question of where exactly R1b-L51 lived before it appeared in central Europe is one of the open problems of the field.

How do you replace the fathers but not the mothers?

Three explanations are discussed, and they are not mutually exclusive.

Mostly men migrated. In 2017, Amy Goldberg, Mattias Jakobsson and colleagues compared ancestry on the X chromosome and on the other chromosomes and estimated that around ten men migrated from the steppe for every woman. The result was immediately challenged. Iosif Lazaridis and David Reich replied that the signal was not robust to the choice of data and method, and that X chromosome comparisons are too sensitive to technical artefacts to support such a precise ratio. The 2019 Iberian study did find less non local ancestry on the X chromosome, but the overall size of the sex bias remains an open question.

Men stayed, women moved. Strontium isotopes, which record where a person spent their childhood, show that most women buried in the Lech valley of Bavaria at the end of the Neolithic and in the Early Bronze Age had grown up elsewhere, while men and children were local (Knipper et al. 2017). The farmstead families reconstructed by Alissa Mittnik and colleagues in 2019 span four to five generations of men, with mothers who had moved in from far away and daughters who left. In such a patrilocal system, a successful lineage of men can keep its Y chromosome intact for centuries while the rest of its genome is constantly mixed with that of incoming wives.

A few men had most of the sons. Even without violence, unequal access to wealth, herds and wives can make a lineage grow far faster than its neighbours. The 15.8% advantage estimated for R1a-M417 in Bohemia is exactly this kind of signature. When it is combined with competition between clans, a single founder's lineage can spread across a continent in a few hundred years.

Plague may have played a part as well. Yersinia pestis has been found in Bronze Age individuals across Eurasia from about 3000 BC (Rasmussen et al. 2015), and some researchers have suggested that it weakened the farming populations before the newcomers arrived. The idea is plausible but still debated, and it would not by itself explain why the losses were concentrated in the male line.

So, did most Europeans descend from a handful of herders?

In the male line, the answer is close to yes. In large parts of western, central and eastern Europe, a majority of men today carry Y chromosomes that trace back to a small number of founders who lived between about 3000 and 2000 BC in communities descended from the steppe herders: R1b-P312 and U106 in the west, R1a-M417 and its branches in the east and north. In Britain and Iberia, the earlier paternal lineages of the farmers who built the megaliths were almost entirely replaced within a few centuries.

In the rest of the genome, the answer is much more modest. Steppe-related ancestry makes up about half of the genome in northern Europe, about a quarter to a third in Iberia, and very little in Sardinia. Every European is also a descendant of Anatolian farmers and of the hunter-gatherers who lived in Europe since the Ice Age, through their mothers above all.

The kurgan fathers did not replace Europe. They replaced its fathers. The women of the Neolithic stayed, married into the new clans, and passed on most of what the newcomers did not bring.

Methods

We used Global25 scaled coordinates by Davidski and the Moriopoulos 2026 collection, merged with first occurrence priority (Global25 population averages, then Global25 modern averages, then the Moriopoulos all averages file without simulations, then the individual dated ancient samples). Distances are Euclidean in the 25 dimensional space. Admixture models use non negative least squares with a sum to one constraint enforced by a heavily weighted extra row (weight 1000). Individuals for Figure 1 were taken from the dated ancient samples file (dates as given in the labels), for England, Scotland, Wales, Spain, Portugal and Czechia between 4200 and 1000 BC, excluding samples flagged as contaminated or duplicated, outliers of non European origin, hunter-gatherers, and samples with coverage below 15%; duplicates of the same individual were counted once. Regional averages were computed from the same file: England Neolithic (n=65), England Bell Beaker and Copper to Early Bronze Age (n=63), England Middle Bronze Age (n=26), Netherlands Bell Beaker (n=15), Iberia Chalcolithic 3200 to 2400 BC (n=32), Iberia Early Bronze Age 2200 to 1550 BC (n=110), Iberia Middle and Late Bronze Age (n=33), Germany Bell Beaker 2500 to 2200 BC (n=41), France Bell Beaker (n=8), Czechia Rivnac and Globular Amphora (n=15), Czechia Corded Ware before and after 2750 BC (n=12 and 25), Czechia Bell Beaker (n=55) and Unetice (n=152). Spike in tests added 2, 3, 5 and 10% of the Samara Yamnaya to the Neolithic averages of each region before refitting. Y chromosome frequencies are taken from the cited studies and are not recomputed here: Global25 contains no uniparental information.

Global25 coordinates used in this article

The source and target populations of our models. They can be pasted directly into the Vahaduo tool.

WHG_Luxembourg_Loschbour,0.130897,0.109677,0.203645,0.198000,0.162492,0.059125,0.015041,0.038075,0.100217,0.016219,-0.015427,-0.017235,0.019921,-0.001239,0.061346,0.070670,0.002608,0.007348,-0.008925,0.065406,0.117543,0.010387,-0.049422,-0.173639,0.019519
Anatolia_Neolithic_Turkey_N,0.117902,0.180087,0.003426,-0.101059,0.051240,-0.047969,-0.003799,-0.006846,0.036167,0.080678,0.008261,0.011309,-0.024164,0.000579,-0.042712,-0.010370,0.022556,0.001388,0.013649,-0.010448,-0.014261,0.005693,-0.004904,-0.003750,-0.004436
Yamnaya_Russia_Samara_EBA,0.125838,0.089254,0.042908,0.115456,-0.027868,0.044685,0.004491,-0.002949,-0.054858,-0.072996,0.001858,0.000350,-0.001652,-0.023610,0.037263,0.015734,0.000000,-0.001478,-0.001704,0.012506,-0.003120,0.001374,0.011229,0.018436,-0.004524
England_Neolithic_avg_n65,0.126571,0.166125,0.054421,-0.027351,0.079878,-0.020346,-0.002762,0.002084,0.056631,0.079301,-0.001294,0.012686,-0.026263,-0.012848,-0.007348,0.004416,0.009719,0.003651,0.003529,-0.002992,0.009574,0.004086,-0.012594,-0.027201,0.000720
Netherlands_BellBeaker_avg_n15,0.128165,0.120442,0.063683,0.073536,0.025317,0.026048,0.002366,0.003508,-0.008276,-0.015514,-0.004807,0.005395,-0.008147,-0.015551,0.026004,0.009387,-0.006945,-0.000507,0.000327,0.007837,0.004991,0.002885,0.000748,0.005318,-0.000056
England_BellBeaker_CEBA_avg_n63,0.125856,0.125104,0.062417,0.064072,0.029236,0.021523,0.003529,0.003249,-0.001419,-0.007333,-0.003668,0.004777,-0.011494,-0.016113,0.025035,0.009313,-0.004899,0.001866,0.001696,0.005967,0.005942,0.003144,-0.000020,0.005792,-0.000133
England_MBA_avg_n26,0.126913,0.130417,0.062167,0.056165,0.033746,0.019029,0.001247,0.003417,0.004696,0.000098,-0.005022,0.004773,-0.010818,-0.014466,0.022623,0.006436,-0.008375,0.001735,0.000508,0.003232,0.004468,0.002901,-0.000493,0.004236,-0.000603
Iberia_Chalcolithic_avg_n32,0.123427,0.166959,0.050416,-0.038477,0.085949,-0.023932,-0.005229,-0.001702,0.063658,0.093020,-0.002273,0.015108,-0.033137,-0.015999,-0.006676,0.000878,0.009587,0.003195,0.000680,-0.002419,0.010025,0.002260,-0.016407,-0.036971,0.000333
Germany_BellBeaker_avg_n41,0.125233,0.131548,0.055805,0.044952,0.034018,0.013883,0.001496,0.002437,0.004709,0.004738,-0.002059,0.006689,-0.012219,-0.013860,0.014760,0.008628,0.000121,0.001696,0.002220,0.004472,0.004985,0.004298,-0.002258,-0.000309,-0.000435
France_BellBeaker_avg_n8,0.131181,0.133034,0.058595,0.049258,0.033583,0.011609,0.001821,0.003259,0.013064,0.000433,-0.002659,0.004908,-0.014885,-0.017186,0.016829,0.012115,0.007709,-0.001584,0.001445,0.005487,0.009655,-0.000232,0.002681,0.004112,0.001287
Iberia_EBA_avg_n110,0.123539,0.155071,0.055855,-0.008002,0.069968,-0.010032,-0.002722,0.001813,0.045830,0.063844,-0.002465,0.012278,-0.024957,-0.016476,0.002349,0.005339,0.005353,0.001602,-0.000169,-0.000900,0.009689,0.002737,-0.010284,-0.023599,0.001773
Iberia_MBA_LBA_avg_n33,0.121687,0.149067,0.055802,0.003582,0.063266,-0.004428,-0.004137,0.002448,0.036734,0.051175,-0.002603,0.011272,-0.023939,-0.015881,0.006679,0.004046,0.002924,-0.000699,0.000758,-0.002406,0.008088,0.002653,-0.008463,-0.015208,0.001604
Czechia_Rivnac_GlobularAmphora_avg_n15,0.124447,0.168781,0.056367,-0.028898,0.084385,-0.020024,-0.000439,0.004354,0.053667,0.071716,-0.000281,0.006015,-0.018682,-0.003863,-0.013644,-0.001750,0.006119,0.003902,0.003980,-0.002768,0.010548,0.004476,-0.014469,-0.030976,-0.000255
Czechia_CordedWare_early_avg_n12,0.123308,0.106123,0.057668,0.097466,0.002872,0.032746,0.004798,0.001904,-0.029366,-0.046880,-0.001908,-0.000450,-0.003134,-0.015333,0.029542,0.011524,-0.004357,0.000686,-0.000188,0.008004,0.000115,0.003998,0.004519,0.016307,-0.003652
Czechia_CordedWare_late_avg_n25,0.123248,0.112764,0.055045,0.083205,0.007423,0.031169,0.004437,-0.000046,-0.026400,-0.035172,-0.001273,-0.001097,-0.005013,-0.013641,0.027361,0.004307,-0.008986,0.000182,0.001493,0.004502,-0.000254,0.003240,0.005019,0.011524,-0.001854
Czechia_BellBeaker_avg_n55,0.126820,0.131927,0.055814,0.046817,0.032537,0.015283,0.003585,0.004955,0.001841,0.002018,-0.000348,0.004232,-0.011496,-0.013327,0.013545,0.009363,0.000282,0.001781,0.002155,0.003356,0.004692,0.003210,-0.001053,0.000548,-0.001047
Czechia_Unetice_avg_n152,0.126052,0.125278,0.059062,0.063943,0.027811,0.022528,0.003904,0.004594,-0.005009,-0.011814,-0.002816,0.002391,-0.006949,-0.011103,0.017301,0.008432,-0.001957,0.000936,0.001292,0.003866,0.003086,0.002950,-0.000135,0.003278,-0.001354
Irish,0.133361,0.134098,0.061169,0.048864,0.037788,0.019352,0.003293,0.004713,0.003568,0.002927,-0.006971,0.005840,-0.014189,-0.014076,0.025935,0.005215,-0.011145,0.001894,0.000597,0.001776,0.005114,0.001279,0.000293,0.014407,0.000661
Basque_Spanish,0.126424,0.148739,0.055679,0.008790,0.055450,0.000249,-0.001754,0.000025,0.029539,0.042923,-0.005214,0.010801,-0.024986,-0.019493,0.015807,0.002614,-0.005630,0.003172,-0.002375,-0.001791,0.008819,0.002204,-0.006479,-0.008654,0.001150

References

1. Y chromosome Batini C, Hallast P, Zadik D, Delser PM, Benazzo A, et al., Jobling MA (2015). Large-scale recent expansion of European patrilineages shown by population resequencing. Nature Communications 6: 7152. doi.org/10.1038/ncomms8152
2. Y chromosome Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, et al. (2015). A recent bottleneck of Y chromosome diversity coincides with a global change in culture. Genome Research 25: 459 to 466. doi.org/10.1101/gr.186684.114
3. Population genetics Zeng TC, Aw AJ, Feldman MW (2018). Cultural hitchhiking and competition between patrilineal kin groups explain the post-Neolithic Y-chromosome bottleneck. Nature Communications 9: 2077. doi.org/10.1038/s41467-018-04375-6
4. Ancient DNA Olalde I, Brace S, Allentoft ME, Armit I, Kristiansen K, et al., Reich D (2018). The Beaker phenomenon and the genomic transformation of northwest Europe. Nature 555: 190 to 196. doi.org/10.1038/nature25738
5. Ancient DNA Olalde I, Mallick S, Patterson N, Rohland N, Villalba-Mouco V, et al., Reich D (2019). The genomic history of the Iberian Peninsula over the past 8000 years. Science 363: 1230 to 1234. doi.org/10.1126/science.aav4040
6. Ancient DNA Papac L, Ernée M, Dobeš M, Langová M, Rohrlach AB, et al., Haak W (2021). Dynamic changes in genomic and social structures in third millennium BCE central Europe. Science Advances 7: eabi6941. doi.org/10.1126/sciadv.abi6941
7. Ancient DNA Haak W, Lazaridis I, Patterson N, Rohland N, Mallick S, Llamas B, et al. (2015). Massive migration from the steppe was a source for Indo-European languages in Europe. Nature 522: 207 to 211. doi.org/10.1038/nature14317
8. Sex bias Goldberg A, Günther T, Rosenberg NA, Jakobsson M (2017). Ancient X chromosomes reveal contrasting sex bias in Neolithic and Bronze Age Eurasian migrations. PNAS 114: 2657 to 2662. doi.org/10.1073/pnas.1616392114
9. Sex bias Lazaridis I, Reich D (2017). Failure to replicate a genetic signal for sex bias in the steppe migration into central Europe. PNAS 114: E3873 to E3874. doi.org/10.1073/pnas.1704308114
10. Isotopes Knipper C, Mittnik A, Massy K, Kociumaka C, Kucukkalipci I, et al., Krause J (2017). Female exogamy and gene pool diversification at the transition from the Final Neolithic to the Early Bronze Age in central Europe. PNAS 114: 10083 to 10088. doi.org/10.1073/pnas.1706355114
11. Ancient DNA Mittnik A, Massy K, Knipper C, Wittenborn F, Friedrich R, et al., Krause J (2019). Kinship-based social inequality in Bronze Age Europe. Science 366: 731 to 734. doi.org/10.1126/science.aax6219
12. Pathogens Rasmussen S, Allentoft ME, Nielsen K, Orlando L, Sikora M, et al., Willerslev E (2015). Early divergent strains of Yersinia pestis in Eurasia 5,000 years ago. Cell 163: 571 to 582. doi.org/10.1016/j.cell.2015.10.009
13. Ancient DNA Patterson N, Isakov M, Booth T, Büster L, Fischer CE, et al., Reich D (2022). Large-scale migration into Britain during the Middle to Late Bronze Age. Nature 601: 588 to 594. doi.org/10.1038/s41586-021-04287-4
14. Y chromosome Balaresque P, Bowden GR, Adams SM, Leung HY, King TE, et al., Jobling MA (2010). A predominantly Neolithic origin for European paternal lineages. PLoS Biology 8: e1000285 (source of the modern R1b frequencies; its Neolithic dating has since been overturned by ancient DNA). doi.org/10.1371/journal.pbio.1000285
15. Ancient DNA Lazaridis I, Patterson N, Anthony D, Vyazov L, Fournier R, et al., Reich D (2025). The genetic origin of the Indo-Europeans. Nature 639: 132 to 142. doi.org/10.1038/s41586-024-08531-5
16. Data Global25 PCA coordinates by Davidski, and the Moriopoulos 2026 collection of Global25 coordinates.