The expansion of R1a1a1-M417 lineages may have disrupted the Early Proto-Indo-European R1b1a1a-P297 community thriving in east Europe. In this context, R1a-M417 lineages might have spoken Uralo-Yukaghir languages when arriving in the Forest Zone from the east, and Uralic could therefore be considered a superstratum over a Pre-Indo-European substratum. A Uralo-Yukaghir community spread over Eurasia is supported by the east-west direction of cultural innovations in the region, and by the finding of maximum Ancient North Eurasian ancestry in modern-day Kets, Mansi, Native Americans, Nganasans and Yukaghirs[Flegontov et al. 2016]. On the other hand, R1a1a1-M417 lineages may have brought a Yukaghir superstratum to the Indo-Uralic spoken in the Forest Zone (an equivalent to Early Proto-Indo-European in this macro-family proposal) by R1b1a1a-P297 communities similar to the Narva samples, developing a Proto-Uralic-speaking community.
Given the early sample of R1a-M420 in the Mesolithic north Pontic area – and maybe the rare subclade R1a5-Z645 found in Estonia[Saag et al. 2017] –, it would also be possible, although unlikely given the available archaeological data, to propose that only pottery was adopted from the east, and that the migration of R1a-M420 subclades (including R1a1a1-M417) happened from the north-west Pontic area, with a back-migration of these lineages to the Baikal region.
In any case, a conservative view will be observed in this paper, assuming Proto-Uralic to be the language of hunter-gatherers in the Forest Zone, north of the Pontic Caspian steppe, at the same time as Middle Indo-European was spoken in the steppes in the transition to the Neolithic[Parpola 2012].
The arrival of N1a1-M46 (previously called N1c1) lineages into Northern Europe has been dated after 5000 BC[Ilumae et al. 2016], coinciding with the TMRCA of N1a1a1a-L708. However, the more recent formation (ca. 3800 BC) and TMRCA (ca. 2300 BC) of common European lineage N1a1a1a1a-L392 point to a late and stepped spread of these hunter-gatherer groups into the Forest Zone, that cannot be associated with the expansion of Pit-Comb Ware cultures. Cultural assimilation remains the best explanation at the moment for the shared Uralic languages of modern R1a1a1-M417 and N1a1-M46 communities. Eastern groups with N1a1a1a1a-L392 lineages may have brought with them the Altaic traits found in Uralic languages[Kortlandt 2010].
Even though an aDNA sample of haplogroup N1a-F1206 is found in the Forest Zone dated ca. 2500 BC at Serteya[Chekunova et al. 2014], it is tempting to place the mass migration of Siberian hunter-gatherer communities around the Urals later, with the expansion of the poorly understood Seima-Turbino phenomenon (which began ca. 2000 BC in East Asia), since it connected cultures from Mongolia to Finland. Three samples of haplogroup NO (xO) found in the Middle Bronze Age Okunev culture, and two samples later in the Chermuchek culture area[Hollard et al. 2014] may give support to this assumption.
- [Anthony 2007] ^ Anthony, D. 2007. The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World. Princeton and Oxford: Princeton University Press.
- [Chekunova et al. 2014] ^ Chekunova, Е.М., N.V. Yartseva, М.К. Chekunov, and А.N. Мazurkevich. 2014. The First Results of the Genotyping of the Aboriginals and Human Bone Remains of the Archeological Memorials of the Upper Podvin’e. // Archeology of the lake settlements of IV—II Thousands BC: The chronology of cultures and natural environment and climatic rhythms. Paper read at Proceedings of the International Conference, Devoted to the 50-year Research of the Pile Settlements on the North-West of Russia., 13-15 November, at St. Petersburg.
- [Flegontov et al. 2016] ^ Flegontov, P., P. Changmai, A. Zidkova, M. D. Logacheva, N. E. Altinisik, O. Flegontova, M. S. Gelfand, E. S. Gerasimov, E. E. Khrameeva, O. P. Konovalova, T. Neretina, Y. V. Nikolsky, G. Starostin, V. V. Stepanova, I. V. Travinsky, M. Triska, P. Triska, and T. V. Tatarinova. 2016. Genomic study of the Ket: a Paleo-Eskimo-related ethnic group with significant ancient North Eurasian ancestry. Sci Rep 6:20768.
- [Fokkens and Harding 2013] ^ Fokkens, Harry, and Anthony Harding. 2013. The Oxford Handbook of European Bronze Age. Oxford: Oxford University Press.
- [Hanks, Epimakhov, and Renfrew 2015] ^ Hanks, B. K., A. V. Epimakhov, and A. C. Renfrew. 2015. Towards a refined chronology for the Bronze Age of the southern Urals, Russia. Antiquity 81 (312):353-367.
- [Hollard et al. 2014] ^ Hollard, C., C. Keyser, P. H. Giscard, T. Tsagaan, N. Bayarkhuu, J. Bemmann, E. Crubezy, and B. Ludes. 2014. Strong genetic admixture in the Altai at the Middle Bronze Age revealed by uniparental and ancestry informative markers. Forensic Sci Int Genet 12:199-207.
- [Ilumae et al. 2016] ^ Ilumae, A. M., M. Reidla, M. Chukhryaeva, M. Jarve, H. Post, M. Karmin, L. Saag, A. Agdzhoyan, A. Kushniarevich, S. Litvinov, N. Ekomasova, K. Tambets, E. Metspalu, R. Khusainova, B. Yunusbayev, E. K. Khusnutdinova, L. P. Osipova, S. Fedorova, O. Utevska, S. Koshel, E. Balanovska, D. M. Behar, O. Balanovsky, T. Kivisild, P. A. Underhill, R. Villems, and S. Rootsi. 2016. Human Y Chromosome Haplogroup N: A Non-trivial Time-Resolved Phylogeography that Cuts across Language Families. Am J Hum Genet 99 (1):163-73.
- [Jaeger 2012] ^ Jaeger, Mateusz. 2012. Enclosed Space - Open Society, Contact and Exchange in the Context of Bronze Age Defensive Settlements in Central Europe. In SAO/SPES, edited by M. Jaeger, J. Czebreszuk and K. P. Fischl. Poznań/Bonn: Bogucki Wydawnictwo Naukowe / Dr. Rudolf Habelt GmbH.
- [Kortlandt 2010] ^ Kortlandt, Frederik. 2010. Indo-Uralic and Altaic revisited. In Transeurasian verbal morphology in a comparative perspective: genealogy, contact, chance. Wiesbaden: Harrassowitz.
- [Krause 2013] ^ Krause, Rüdiger. 2013. Die bronzezeitliche Sintašta-Kultur im Trans-Ural – Impulsgeber in der Eurasischen Steppe. In Landschaft, Besiedlung und Siedlung. Archäologische Studien im nordeuropäischen Kontext, edited by I. Heske, H.-J. Nüsse and J. Schneeweiss. Neumünster/Hamburg: Wachholtz.
- [Kristiansen and Larsson 2005] ^ Kristiansen, Kristian, and Thomas B. Larsson. 2005. The Rise of Bronze Age Society: Travels, Transmissions and Transformations. Cambridge: Cambridge University Press.
- [Meller et al. 2015] ^ Meller, Harald, Helge Wolfgang Arz, Reinhard Jung, and Roberto Risch. 2015. 2200 BC - A climatic breakdown as a cause for the collapse of the old world? 7th Archaeological Conference of Central Germany October 23-26, 2014 in Halle (Saale). Halle (Saale).
- [Parpola 2012] ^ Parpola, Asko. 2012. The problem of Samoyed origins in the light of archaeology: On the formation and dispersal of East Uralic (Proto-Ugro-Samoyed). Mémoires de la Société Finno-Ougrienne (264).
- [Saag et al. 2017] ^ Saag, Lehti, Liivi Varul, Christiana Lyn Scheib, Jesper Stenderup, Morten E Allentoft, Lauri Saag, Luca Pagani, Maere Reidla, Kristiina Tambets, Ene Metspalu, Aivar Kriiska, Eske Willerslev, Toomas Kivisild, and Mait Metspalu. 2017. Extensive farming in Estonia started through a sex-biased migration from the Steppe. bioRxiv.