How was agriculture disseminated? The case of Europe

© Paul Gepts 1995-2011


Return to course home page



PLB143: Readings - Lecture 12

  • Required reading:
    • Barbujani G, Pilastro A (2003) Genetic evidence on origin anddispersal of human populations speaking languages of the Nostratic macrofamily. Proc. Nat. Acad. Sci. USA 90: 4670-4673 UCD Access only (Kerberos password)
  • Suggested readings:
    • Ammerman AJ, Cavalli-Sforza LL (1984) The Neolithic transitionand the genetics ofpopulations in Europe. Princeton Univ. Press, Princeton, NJ: Chapter 7: pp. 109-132  UCD Access only (Kerberos password)
    • Sokal RR (1991) The continental population structure of Europe. Ann. Rev. Anthropol.20: 119-140.
    • Sokal RR, Oden NL, Wilson C (1991) Genetic evidence for the spread of agriculturein Europe by demic diffusion. Nature 351: 143-145.
    • Piazza A (1993) Who are the Europeans? Science 260: 1767-1769
    • Fowler B (2000) The Iceman. Random House
    • GEO - Der Man aus der Steinzeit: http://www.geo.de/themen/historie/oetzi/
    • Nova Online: The Iceman's last meal: http://www.pbs.org/wgbh/nova/icemummies/iceman.html
  • Presentation slides

Disssemination of crops

  • Modes
    • Human migration
    • Cultural exchange
    • Trade
    • Warfare
    • Scientific exploration
  • Introduction into Europe
    • From the Near East; 9,000 BP

Why Europe?

  • Substantial amount of data available
    • archaeological data: dated (14C) plant remains
    • human population data
      • anthropometry
      • osteometric: e.g. craniometry
      • dermatoglyph
      • cultural: e.g., language
      • genetic: genotypic!



Archaeological data for the spread of agriculture into Europe

  • Dating of plant remains
    • domesticated elsewhere
      • emmer wheat
      • barley
    • local domesticates:
      • oat
  • Material culture:
    • ceramic: e.g., Bandkeramik (Linear Pottery) in Central Europe:
    • settlement patterns: near water and arable land, i.e. most favorable sites:
    • houses: rectangular shape; timber framework and earth-covered walls: Example:     Map of an excavation in Vaihingen, Germany : notice the rectangular shapes representing the foundations of several houses;  Longhouse
    • social organization
    • sedentism
  • Results:
    • Spread of agriculture started in 9,000 BP; complete in 5,000 BP:
    • linear progression of agriculture into Europe: 1 km/yr:

Some related sites of interest

  • Examples of Bandkeramik
     Bandkeramik

    Bandkeramik
  • Settlements
    valley villages village
  • Aerial photo of an excavation showing the rectangular house shape
    Excavation ,




The "Iceman" or "Oetzi," an early agricultural inhabitant of Europe

  • Discovered in 1991 in the Alps on the border of Italy and Austria
    • Dated to 5100-5350 yrs BP
    • 1.60 m; 40-45 years  

  • Clothing and gear!
    • See drawings to the right
  • Agricultural context of the Iceman (Fowler 2000)
    • Last meal
      • main ingredient: einkorn, based on remains in colon
      • charcoal: einkorn used to make "bread" (cracker-like), baked over open fire
      • pollen of hop hornbeam tree: March-June, south of mountains
    • Also einkorn grains found in clothing



  • Oetzi body

    (from Fowler 2000)
  • Successive layers of clothing
      ,
      , and 

    (from Fowler 2000)

What was the mechanism of spread of agriculture into Europe?

Theoretically, two extreme types of diffusion:

  • Cultural diffusion:
    • i.e. techniques , ideas, and materials are passed along and learned
    • no movement of people
    • certain continuity in culture between mesolithic and neolithic
    • stronger cultural differentiation
  • Demic diffusion:
    • i.e. techniques travel with people
    • population growth and short-distance migration (i.e. not colonization)
    • migrants would maintain continuity in social and cultural context

Which type of diffusion was involved here?


Population growth associated with the introduction of agriculture

  • Population densities:
    • hunter-gatherers (Pacific Northwest): 0.01-1/sq. km
    • agriculturalists: 3 -300/sq. km
  • Same life expectancy (= death rate) + increased birth rate (child spacing from 4yrs to 2.5 yrs. Why?
    • sedentism
    • labor


Model for population growth

"Wave-of-advance" (Fisher 1936)

  • Two major factors:
    • population growth: a: e.g., 2%
    • limited migratory activity: M: relocation to adjacent, unoccupied land:
      • hunters-gatherers (e.g., Pygmies): average distance between known sites: male: 88km; female: 57 km
      • farmers: average mating distance: 12-13 km
  • Generates "wave": 
    • population growth rate is largest at front of the wave
    • population growth rate is 0 behind wave: carrying capacity 
  • Prediction for gene frequencies:
    • cultural model: no change
    • demic model: replacement of alleles
    • mixed model: gradient of allele frequencies
  • Interactions between hunter- gatherers and farmers:
    • acculturation = gene flow
    • warfare
    • disease
    • mutualism






  • Wave of advance generated by population growth


  • Population growth rates

Analyses of genetic data

  • Types: 26 genetic marker systems
    • red cell antigens: e.g., ABO
    • plasma proteins
    • enzymes: e.g., PGM
    • HLA alleles: 
    • immunoglobulins
  • Locations: 33-870; total of 3,373. Individuals/location: 50 -->1,000s
  • Statistical analysis: "ordination": e.g., Principal Component Analysis
    • reduce number of dimensions
    • limited number of dimensions, i.e. principal components
    • decreasing order of variance accounted for by principal components
Results of Principal Component Analyses
  • Outliers:
    • Lapps: fron N. Siberian people (Samoyeds); Uralic family language
    • Basques and Irish: direct descendants of earliest post-Neanderthal occupants in Europe; Paleolithic:40,000 BP (see cave art!)  
    • Sardinians: influx from Paleolithic, Neolithic farmers, Phoenicians, Carthaginians,Greeks, etc. Overall similarity to Lebanese

  • Major trends:
    • First principal component: S. E. <--> N.W. gradient corresponding presumably to the introduction of agriculture   
    • Second principal component: N. <--> S. or S.W. <--> N.W. gradient: adaptation to temperatureor partition between Indo-European and Uralic languages? 
    • Third principal component: E. <--> W. gradient: "Kurgan" culture originating in Eurasian steppes



  • HLA allele frequencies




  • Outliers of principal component analysis


  • Principal component analyses


  • Origin of the Indo-Europeans in Europe? First or third component
    • Renfrew
      • Near-East --> Greece (8,500 BC)  --> rest of Europe
    • Gimbutas
      • "Kurgan": russian for barrow (cart)
      • southern steppes of Ukraine (e.g.,Yamna culture) --> eastern Europe (Danube, Carpathian bassin) (3,300 BC)
      • linguistic arguments & archaeological: horseback riding, wheeled vehicles

  • Four language family putatively descended from an original language, Nostratic, spoken in the Near Eastern Center of origin. Four major migrations from this center, each giving rise to a different language family. Correlated with genetic data:
    • Indo-European: towards Northwest (Europe) and Southwest (Iran, Pakistan, and India)
    • Afro-Asiatic: Arabian peninsula and northern Africa
    • Altaic: central Asia
    • Elamo-Dravidian: towards Southwest (same as Indo-European but earlier)

  • Putative relationship between agricultural migrations and language families

     Eurasia map with language family distribution


Computer simulation study

  • Divide European territory into rectangular lattice; determine population or genefrequencies in each cell of the lattice
  • First stage: 11,000-8,000 BC:
    • Hunter-gatherers
      • low density: 0.02/sq.km
      • genetic drift (chance) + some migration
      • no general large scale patterns
  • Second stage: 8,000-4,000 BC: 
    • Spread of early farming from Near East:
      • 120 generations to reach N.W. Europe
      • S.E. --> N.W. gradient in gene frequencies
  • Third stage: 4,000-0 BC:
    • Subsequent demic events
      • Two demic events simulated (see PCA)
      • Overall gradient established in second stage is maintained
  • Fourth stage: 0-2,000 AD
    • Ongoing evolution
      • No other major migration but reciprocal shorter-distance migration between adjacentregions
  • Overall analysis with model: recreates S.E. gradient <--> N.W.







  • First stage: Hunter-gatherers



  • Second stage: Early spread



  • Overall analysis



Conclusion

  • Striking persistence of gene frequency patterns resulting from ancient events
  • Spread of agriculture in Europe: demic diffusion + admixture between hunter-gatherersand agriculturalists
  • Ammerman and Cavalli-Sforza (1984): " In the case of evolutionary ... reconstructions,we are not dealing with phenomena that are occurring under controlled conditions and that can be repeated at will in the laboratory... . Confidence in reconstructions is built by the development of multiple lines of evidence that generate independent support for a particular interpretation. Ultimately, it is the growth of new evidence in individual fields and the creation of expectations for findings in other fields that generate a dense network for evaluating a reconstructive hypothesis. "


Return to course home page