1 Czebreszuk, J. In Ancient Europe, 8000 b.c. to a.d. 1000: An Encyclopedia of the Barbarian World (eds Bogucki, P. I. & Crabtree, P. J. ) 476–485 (Charles Scribner’s Sons, 2004)

2 Haak, W. et al. Massive migration from the steppe was a source for Indo-European languages in Europe. Nature 522, 207–211 (2015)

3 Allentoft, M. E. et al. Population genomics of Bronze Age Eurasia. Nature 522, 167–172 (2015)

4 Mathieson, I. et al. Genome-wide patterns of selection in 230 ancient Eurasians. Nature 528, 499–503 (2015)

5 Czebreszuk, J. Similar But Different. Bell Beakers in Europe (Adam Mickiewicz Univ., 2004)

6 Cardoso, J. L. Absolute chronology of the Beaker phenomenon north of the Tagus estuary: demographic and social implications. Trab. Prehist. 71, 56–75 (2014)

7 Jeunesse, C. The dogma of the Iberian origin of the Bell Beaker: attempting its deconstruction. J. Neolit. Archaeol. 16, 158–166 (2015)

8 Fokkens, H. & Nicolis, F. Background to Beakers. Inquiries into Regional Cultural Backgrounds of the Bell Beaker Complex (Sidestone, 2012)

9 Linden, M. V. What linked the Bell Beakers in third millennium bc Europe? Antiquity 81, 343–352 (2007)

10 Fu, Q. et al. An early modern human from Romania with a recent Neanderthal ancestor. Nature 524, 216–219 (2015)

11 Lazaridis, I. et al. Ancient human genomes suggest three ancestral populations for present-day Europeans. Nature 513, 409–413 (2014)

12 Lazaridis, I. et al. Genomic insights into the origin of farming in the ancient Near East. Nature 536, 419–424 (2016)

13 Mallick, S. et al. The Simons Genome Diversity Project: 300 genomes from 142 diverse populations. Nature 538, 201–206 (2016)

14 Valverde, L. et al. New clues to the evolutionary history of the main European paternal lineage M269: dissection of the Y-SNP S116 in Atlantic Europe and Iberia. Eur. J. Hum. Genet. 24, 437–441 (2016)

15 Gamba, C. et al. Ancient DNA from an Early Neolithic Iberian population supports a pioneer colonization by first farmers. Mol. Ecol. 21, 45–56 (2012)

16 Günther, T. et al. Ancient genomes link early farmers from Atapuerca in Spain to modern-day Basques. Proc. Natl Acad. Sci. USA 112, 11917–11922 (2015)

17 Alexander, D. H., Novembre, J. & Lange, K. Fast model-based estimation of ancestry in unrelated individuals. Genome Res. 19, 1655–1664 (2009)

18 Broushaki, F. et al. Early Neolithic genomes from the eastern Fertile Crescent. Science 353, 499–503 (2016)

19 Skoglund, P. et al. Genomic diversity and admixture differs for Stone-Age Scandinavian foragers and farmers. Science 344, 747–750 (2014)

20 Olalde, I. et al. A common genetic origin for early farmers from Mediterranean Cardial and central European LBK cultures. Mol. Biol. Evol. 32, 3132–3142 (2015)

21 Mathieson, I. et al. The genomic history of southeastern Europe. Nature https://doi.org/10.1038/nature25778 (2018)

22 Lipson, M. et al. Parallel palaeogenomic transects reveal complex genetic history of early European farmers. Nature 551, 368–372 (2017)

23 Cassidy, L. M. et al. Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome. Proc. Natl Acad. Sci. USA 113, 368–373 (2016)

24 Sheridan, J. A. In Landscapes in Transition (eds Finlayson, B. & Warren, G. ) 89–105 (Oxbow, 2010)

25 Burger, J., Kirchner, M., Bramanti, B., Haak, W. & Thomas, M. G. Absence of the lactase-persistence-associated allele in early Neolithic Europeans. Proc. Natl Acad. Sci. USA 104, 3736–3741 (2007)

26 Clarke, D. L. In Glockenbecher Symposion, Oberried, 18–23 März 1974 (eds Lanting, J. N. & van DerWaals, J. D. ) 460–477 (Bussum, 1976)

27 Clark, G. The invasion hypothesis in British archaeology. Antiquity 40, 172–189 (1966)

28 Brotherton, P. et al. Neolithic mitochondrial haplogroup H genomes and the genetic origins of Europeans. Nat. Commun. 4, 1764 (2013)

29 Desideri, J. When Beakers Met Bell Beakers: an Analysis of Dental Remains (British Archaeological Reports International Series 2292) (Archaeopress, 2011)

30 Parker Pearson, M. et al. Beaker people in Britain: migration, mobility and diet. Antiquity 90, 620–637 (2016)

31 Shennan, S. et al. Regional population collapse followed initial agriculture booms in mid-Holocene Europe. Nat. Commun. 4, 2486 (2013)

32 Valtueña, A. A. et al. The Stone Age plague and its persistence in Eurasia. Curr. Biol. 27, 3683–3691 (2017)

33 Rasmussen, S. et al. Early divergent strains of Yersinia pestis in Eurasia 5,000 years ago. Cell 163, 571–582 (2015)

34 Dabney, J. et al. Complete mitochondrial genome sequence of a Middle Pleistocene cave bear reconstructed from ultrashort DNA fragments. Proc. Natl Acad. Sci. USA 110, 15758–15763 (2013)

35 Damgaard, P. B. et al. Improving access to endogenous DNA in ancient bones and teeth. Sci. Rep. 5, 11184 (2015)

36 Korlević, P. et al. Reducing microbial and human contamination in DNA extractions from ancient bones and teeth. Biotechniques 59, 87–93 (2015)

37 Rohland, N., Harney, E., Mallick, S., Nordenfelt, S. & Reich, D. Partial uracil–DNA–glycosylase treatment for screening of ancient DNA. Philos. Trans. R. Soc. Lond. B 370, 20130624 (2015)

38 Briggs, A. W. et al. Removal of deaminated cytosines and detection of in vivo methylation in ancient DNA. Nucleic Acids Res. 38, e87 (2010)

39 Maricic, T., Whitten, M. & Pääbo, S. Multiplexed DNA sequence capture of mitochondrial genomes using PCR products. PLoS ONE 5, e14004 (2010)

40 Kircher, M., Sawyer, S. & Meyer, M. Double indexing overcomes inaccuracies in multiplex sequencing on the Illumina platform. Nucleic Acids Res. 40, e3 (2012)

41 Behar, D. M. et al. A ‘Copernican’ reassessment of the human mitochondrial DNA tree from its root. Am. J. Hum. Genet. 90, 675–684 (2012)

42 Li, H. & Durbin, R. Fast and accurate short read alignment with Burrows–Wheeler transform. Bioinformatics 25, 1754–1760 (2009)

43 Fu, Q. et al. A revised timescale for human evolution based on ancient mitochondrial genomes. Curr. Biol. 23, 553–559 (2013)

44 Sawyer, S., Krause, J., Guschanski, K., Savolainen, V. & Pääbo, S. Temporal patterns of nucleotide misincorporations and DNA fragmentation in ancient DNA. PLoS ONE 7, e34131 (2012)

45 Korneliussen, T. S., Albrechtsen, A. & Nielsen, R. ANGSD: analysis of next generation sequencing data. BMC Bioinformatics 15, 356 (2014)

46 Li, H. et al. The sequence alignment/map format and SAMtools. Bioinformatics 25, 2078–2079 (2009)

47 Weissensteiner, H. et al. HaploGrep 2: mitochondrial haplogroup classification in the era of high-throughput sequencing. Nucleic Acids Res. 44, W58–W63 (2016)

48 van Oven, M. & Kayser, M. Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation. Hum. Mutat. 30, E386–E394 (2009)

49 Patterson, N. et al. Ancient admixture in human history. Genetics 192, 1065–1093 (2012)

50 Raghavan, M. et al. Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans. Nature 505, 87–91 (2014)

51 Omrak, A. et al. Genomic evidence establishes Anatolia as the source of the European Neolithic gene pool. Curr. Biol. 26, 270–275 (2016)

52 Gallego Llorente, M. et al. Ancient Ethiopian genome reveals extensive Eurasian admixture in Eastern Africa. Science 350, 820–822 (2015)

53 Fu, Q. et al. The genetic history of Ice Age Europe. Nature 534, 200–205 (2016)

54 Kılınç, G. M. et al. The demographic development of the first farmers in Anatolia. Curr. Biol. 26, 2659–2666 (2016)

55 Gallego-Llorente, M. et al. The genetics of an early Neolithic pastoralist from the Zagros, Iran. Sci. Rep. 6, 31326 (2016)

56 Olalde, I. et al. Derived immune and ancestral pigmentation alleles in a 7,000-year-old Mesolithic European. Nature 507, 225–228 (2014)

57 Hofmanová, Z. et al. Early farmers from across Europe directly descended from Neolithic Aegeans. Proc. Natl Acad. Sci. USA 113, 6886–6891 (2016)

58 Patterson, N., Price, A. L. & Reich, D. Population structure and eigenanalysis. PLoS Genet. 2, e190 (2006)

59 Purcell, S. et al. PLINK: a tool set for whole-genome association and population-based linkage analyses. Am. J. Hum. Genet. 81, 559–575 (2007)

60 Busing, F. M. T. A., Meijer, E. & Van Der Leeden, R. Delete-m jackknife for unequal m. Stat. Comput. 9, 3–8 (1999)

61 Rojo-Guerra, M. Á ., Kunst, M ., Garrido-Pena, R . & García-Martínez de Lagrán, I. & Morán-Dauchez, G. Un desafío a la eternidad. Tumbas monumentales del Valle de Ambrona (Memorias Arqueología en Castilla y León 14) (Junta de Castilla y León, 2005)