Donnerstag, 31. Dezember 2015

Europe is based on Migration, Cooperation and Adaptation – A brief glance at long time scales

Detlef Gronenborn
 


From both historic and archaeological perspectives migration forms a fundamental component in constituting European societies. Archaeological, as well as more recently, also genetic research shows that phases of population stasis were followed by phases of often rapid population change. In fact, since about 7000 years ago a considerable proportion of the European population stock has been of Near Eastern ancestry. These people arrived from the western Eurasian centre of origin for agriculture, the so-called Fertile Crescent, exactly the same region from which also today people strive to reach Europe.

But migration to Europe goes back much deeper into the past as the early archaic humans arrived between a million to 800.000 years ago from Africa, via the Near East. Lastly this means that we are all of African descent.

Possibly somewhat strife-ridden might have been the arrival of the anatomically modern humans about 40.000 years ago, again from Africa. These people were our direct ancestors. They came into contact with Neanderthal populations and appear to have pushed those back to the western marginal zones of the Eurasian land mass. However, occasionally these populations seem to have mixed so that about 1,5 to 2 % of the modern European DNA pool is of Neanderthal origin (Prüfer et al. 2014).

Those immigrant anatomically modern humans constituted the European population stock for the next 33.000 years, well until the Ice Age or Glacial was over. While there are indications for occasional small-scale migrations during the early post-Glacial millennia, the next great population change occurs only with the expansion of farming to Europe, 7000 years ago. Now people with an entirely new technology and economy arrive in Southern, Temperate and Western Europe. Largely, two routes have been taken, one - land-based - went from Anatolia via Greece, the Balkans, and Hungary lastly to Central Europe (Gronenborn 1999; Szécsényi-Nagy et al. 2015; Horejs et al. 2015). Interestingly enough, those are exactly the same routes as they are currently being taken by refugees from Syria and other parts of western Asia. Also, the regions of origin are more or less the same: the Fertile Crescent around the river valleys of the Euphrates and Tigris, and the surrounding landscapes. One reason for those past migrations might have been climate fluctuations as rising populations would have faced subsistence difficulties during periods of adverse climatic conditions (Weninger et al. 2014).

Apart from the way into Europe by land, across the Balkans, another route was taken by seaborne settlers along the Mediterranean coasts. Those farmers eventually made it to the Iberian Peninsula and into North-West Africa where they settled and introduced farming and animal husbandry (Paschou et al. 2014).
Spread of agriculture in Western Eurasia. Farming as well as their cereals and husbandry originate from the Fertile Crescent (orange).
(Graphics: D. Gronenborn/ M. Ober, RGZM)

In many regions of continental Europe, particularly in the West, did the immigrant population come into contact with indigenous hunter-gatherers. These contact situations have been examined by archaeology for many decades: farmers and indigenous hunter-gatherers seem to have benefited form each other and may have lived, side by side, in the same villages, each with their respective economies and specialisations (Gronenborn 2007). In marginal landscapes and in the coastal regions, hunting and gathering persisted, sometimes for millennia, aside farming communities settling on more fertile soils.

Every recent study on genome-wide ancient DNA from hunter-gatherer and farming individuals revealed information on physical differences between those populations much beyond the classic physical anthropology studies. Apparently the indigenous hunter-gatherer population was rather dark-skinned, yet with light eyes, while the population migrating from Anatolia was lighter skinned and dark-eyed (Mathieson et al. 2015). These physical differences, but maybe much more the fundamental differences in languages, rites, and customs may be the reason that, in many regions, for millennia the admixture between immigrant farming and indigenous hunting and gathering populations was rather negligible. Nevertheless those societies knew of each other, communicated and cooperated.

During this period of early farming – the Neolithic – an accumulation and assimilation process sets in, which is largely finalized around 4200 years ago. Now a new population sweeps across large parts of Europe with its origins in the steppe regions of present-day south-eastern Russia and the Ukraine. With the onset of the Bronze Age European societies are genetically largely constituted in their present form, migration rates are much lower in the following millennia (Brandt et al. 2013).

Summing up, the current picture is that the present European population is composed of three large components, each attributable to extensive migration events in the deep past: One component dates back to the Ice Age and arrived in Europe about 40.000 years ago, the next component came with the onset of farming about 7000 years ago and the last arrived from the steppes around 5000 years ago (Haak et al. 2015).

Eventually all these populations mixed, integrated and cooperated, lastly not only formed present-day Europe but also contributed to the Early Modern population mix in the Americas, in Southern Africa, and as far away as Australia and New Zeeland.


References and further reading:
  • Brandt, Guido; Haak, Wolfgang; Adler, Christina J. et al., Ancient DNA Reveals Key Stages in the Formation of Central European Mitochondrial Genetic Diversity. Science 342, 2013, 257-261.
  • D. Gronenborn, A variation on a basic theme: the transition to farming in southern central Europe. Journal of World Prehistory 13/2, 1999, 123-210.
  • D. Gronenborn, Beyond the Models: ‘Neolithization’ in Central Europe. In: A. Whittle / V. Cummings (Hrsg.), Going Over: the Mesolithic-Neolithic Transition in North-West Europe. Proceedings of the British Academy 144 (London 2007) 73-98.
  • D. Gronenborn / Th. Terberger, Die ersten Bauern in Mitteleuropa – eine interdisziplinäre Herausforderung. In: Th. Terberger / D. Gronenborn (Hrsg.), Vom Sammler und Jäger zum Bauern: Die Neolithische Revolution. Konrad Theiss (Darmstadt 2014) 7-14.
  • Haak, Wolfgang; Lazaridis, Iosif; Patterson, Nick; Rohland, Nadin; Mallick, Swapan; Llamas, Bastien et al., Massive migration from the steppe was a source for Indo-European languages in Europe. Nature 522 (7555), 2015, 207–211. - DOI: 10.1038/nature14317.
  • Horejs, B.; Milić, B.; Ostmann, F.; Thanheiser, U.; Weninger, B.; Galik, A., The Aegean in the Early 7th Millennium BC. Maritime Networks and Colonization. Journal of World Prehistory 28 (4), 2015, pp. 289–330. - DOI: 10.1007/s10963-015-9090-8. (at academia.edu)
  • Mathieson, Iain; Lazaridis, Iosif; Rohland, Nadin; Mallick, Swapan; Patterson, Nick; Roodenberg, Songül Alpaslan et al. (2015): Genome-wide patterns of selection in 230 ancient Eurasians. Nature 528, 2015, pp. 499-503. - DOI: 10.1038/nature16152.
  • Paschou, Peristera; Drineas, Petros; Yannaki, Evangelia; Razou, Anna; Kanaki, Katerina; Tsetsos, Fotis et al. (2014): Maritime route of colonization of Europe. Proceedings of the National Academy of Sciences of the United States of America 111 (25), 2014, pp. 9211–9216. - DOI: 10.1073/pnas.1320811111.
  • Prüfer, Kay; Racimo, Fernando; Patterson, Nick; Jay, Flora; Sankararaman, Sriram; Sawyer, Susanna et al., The complete genome sequence of a Neanderthal from the Altai Mountains. Nature 505 (7481), 2014, 43–49. - DOI: 10.1038/nature12886.
  • Sankararaman, Sriram; Mallick, Swapan; Dannemann, Michael; Prüfer, Kay; Kelso, Janet; Pääbo, Svante; Patterson, Nick; Reich, David, The genomic landscape of Neanderthal ancestry in present-day humans. Nature 507 (7492), 2014,354–357. - doi:10.1038/nature12961
  • Szécsényi-Nagy, Anna; Brandt, Guido; Haak, Wolfgang; Keerl, Victoria; Jakucs, János; Möller-Rieker, Sabine et al. (2015): Tracing the genetic origin of Europe's first farmers reveals insights into their social organization. Proceedings. Biological sciences / The Royal Society 282 (1805), 2015. - DOI: 10.1098/rspb.2015.0339.
  • Weninger, Bernhard; Clare, Lee; Gerritsen, Fokke; Horeijs, Barbara, Krauß, Raiko; Linstädter, Jörg; Ozbal, Rana; Rohling, Eelco J., Neolithisation of the Aegean and Southeast Europe during the 6600–6000 calBC period of Rapid Climate Change. Documenta Praehistorica 41, 2014, pp. 1–31. - DOI: 10.4312\dp.41.1

Link

This is an extended version of the German contribution:



http://web.rgzm.de/
Prof. Dr. Detlef Gronenborn is an archaeologist at the  RGZM (Römisch-Germanisches Zentralmuseum), teaching at  Mainz university. His research currently focuses on the Neolithic in Temperate Europe and on Iron Age to pre-Modern West and Southern Africa.
http://www.staff.uni-mainz.de/gronenbo/
http://web.rgzm.de/no_cache/ueber-uns/team/m/detlef_gronenborn.html


1 Kommentar:

Rainer Schreg hat gesagt…

aufgegriffen bei http://bookforum.com/blog/15876