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Monday, May 25, 2015

High female mobility in Bronze Age Europe


I have a feeling that this generally underrated phenomenon will become much less underrated in the near future, and might even be recognized as a major factor in the formation of the modern European gene pool.

Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of highresolution human mobility.

Frei, K.M. et al. Tracing the dynamic life story of a Bronze Age Female. Sci. Rep. 5, 10431; doi: 10.1038/srep10431 (2015).

At the transition from the third to the second millennium BC, the introduction of bronze for the manufacture of tools, weapons and personal ornaments marked a major step in European prehistory. Trade of the metal raw materials and manufactured goods required regular and organized contacts among communities. On the other hand, local population continuity was a prerequisite for the accumulation of wealth, the establishment of enduring social differentiation, and the formation of regional elites.

The archeological record in the Lech Valley in southern Bavaria, Germany, shows a rapid and gapless transition from the Late Neolithic Bell Beaker Phenomenon to the Early Bronze Age. To investigate social and demographic changes associated with the appropriation of the bronze technology, we studied nearly eighty individuals from six burial sites in the region with respect to their maternally inherited mitochondrial DNA (mtDNA).

The results indicate both local genetic continuity spanning the cultural transition, and, following the onset of the Early Bronze Age, a major influx of mtDNA types previously not found in this region. Integrating stable isotope data with the genetic data reveals a picture of a patrilocal society with remarkable mobility in women. While crucial for understanding the change of local demographics, these findings also have implications for the spread of major technological and societal changes across Europe at the beginning of the Bronze Age.

Mittnik et al., Ancient DNA reveals patterns of residential continuity and mobility at the onset of the Central European Bronze Age, Society for Molecular Biology and Evolution (SMBE) 2015 abstract

See also...

Female mobility and exogamy as the main drivers of foreign admixture during the Late Neolithic/Early Bronze Age shift in Central Europe (Knipper et al. 2017)

Corded Ware women more mobile than their men (Sjögren et al. 2016)

22 comments:

Grey said...

"I have a feeling that this generally underrated phenomenon will become much less underrated in the near future, and might even be recognized as a major factor in the formation of the modern European gene pool."

Agree.

Bell Beaker trade networks would be my guess with BB marrying endogamously within themselves but over long distances between trade nodes and also marrying women into the local elite at each node for alliance building reasons and thus spreading those specific clades of mtdna H from Iberia.

Mike Thomas said...

David

Thanks for highlighting these great studies

Actually, the practice of exogamy is not underrated. In fact, it has well been recognized (at least hypothesized) long before genetic and isotopic studies.

The issue here is whether it can account for the entirety of what we see, eg in the Samara Yamnaya genomes.

My cautions relate to:

1) exogamy is a selective social process, and not a mass phenomenon which might account for some figure of 40% admixture rate.

2) it is usually done for social advantage, alliance building, etc. What social advantage would elites of the southern "farming" communities have in marrying off the women to peripheral hunter -gatherers on the Samara or Khvalynsk region steppe ? (and this was long before the day of Sintastha, etc) In the case of Majkop, I'd understand.

3) the first study actually suggests it was a bi-directional process. Ie there was a life-cycle mobility

4) The second suggests a massive influx of *women*. Aren't the changes see in LN Europe thought to be (predominantly) due to invading steppic men ?

Of course, these "what-ifs" don't mean that such mass genetic change through exogamy isn't possible. I'd just like to see a little more proof. Gladly, we all know such studies are on the way.

Davidski said...

It looks like it took a couple of thousand years for the southern ancestry on the steppe to reach 40 or 50%, depending on how literally we take the modeling in Haak et al. So it wasn't a sudden process and the women probably didn't come from one culture and area.

I don't see why the Khvalynsk culture wouldn't be involved in this sort of thing to some extent? The Khvalynsk people traded with cultures as far as the Balkans and Caucasus.

Indeed, it might have been a bidirectional process, with steppe women also moving south into the Caucasus and even the Near East.

And yes, the male dominated migrations from the steppe also happened, but it was a different process probably triggered by very different factors.

Mike Thomas said...

Yes, I agree.

Nirjhar007 said...

Ah Nice Study, Just that I don't buy which David wants to come true that Samara-Yamnaya got their NE like ancestry from Females only there were Male intrusions certainly from the South, investigations from specific areas will certainly show that, actually imo Male migrate more rapidly than women......

Nirjhar007 said...

Ah Yes Some Interesting News from India-
http://njsaryablog.blogspot.in/2015/05/i-came-to-know-about-discovery-from.html

a said...

Using MLDP-world9 calc and comparing Caucaus_Parsia component among some ancient/modern r1b-z2103+r1a [5k+/-]samples + [36K+/-Kostenki 14].

# Population Percent
1 North_and_East_European 53.15
2 Caucaus_Parsia 29.66
3 South_and_West_European 10.81
4 Arctic_Amerind 3.86
5 Indian 1.84

# Population Percent
1 North_and_East_European 50.53
2 South_and_West_European 38.68
3 Caucaus_Parsia 7.67
4 Indian 1.42
5 Middle_East 1.36

Comparing kostenki14 [36K+/- slightly to the West of Yamnaya sampled regions, but still within Yamnaya horizon-European Russia]
http://news.sciencemag.org/archaeology/2014/11/european-genetic-identity-may-stretch-back-36000-years

MDLP World Oracle results:
Kit F999936

Admix Results (sorted):

# Population Percent
1 North_and_East_European 27.42
2 South_and_West_European 21.47
3 Indian 16.01
4 Caucaus_Parsia 10.31
5 Middle_East 6.73
6 Melanesian 4.51
7 Arctic_Amerind 4.43
8 East_Asian 3.13
9 Sub_Saharian 2.53
10 Mesoamerican 1.84
11 Paleo_African 1.54
12 North_Asian 0.07

a said...

^^^
Above correction. 1 sample from R1b Eastern Europe. 1 R1b Sample from Samara and 1 sample from K14= ydna C. :)

Yuri said...

In the Pacific, where Austronesians were matrilocal, in some populations nearly 100% of the Y-DNA is native while nearly 100% percent of the mtDNA is Austronesian. It doesn't mean that Austronesian women married Papuan men en masse, of course, but probably the combined effect over time of matrilocality followed by further migration, plus bottlenecks as they hopped from island to island. Something important is that many of these Papuans were at a technological disadvantage, and yet for some reason they continued to marry into the Austronesians, so obviously this was no obstacle (like the ressurgence of hunter-gatherer Y-DNA after the European early Neolithic?)

I wonder if something similar, though the opposite, because of patrilocality, could have happened in parts of North Eurasia. Up until the 19th century, when war and the Russian presence disrupted traditional lifestyles, there were seasonal migrations between the Steppe and the Caucasus for trade and in search of pastures (and further back possibly for hunting purposes). Couldn't the Steppe folks be trading metals and game from further north and forging alliances with those in the south through marriage? The end result isn't nearly as spectacular as in the case of the Oceanic Austronesians, of course, but still significant.

Nirjhar007 said...

a,
Those who don't know much about those stuff you just showed:), can you generally tell that what they mean? specially the first.

a said...

Nirjhar007
Sorry I don't think they have a firm understanding. Otherwise they would be more specific about the differences in the snp's[regional distribution] found in Yamnaya samples and various N.E populations. You do realize that K14 is on the magnitude 30+ thousand years older than the Yamnaya samples right? Yet comparing World 9 shows somewhat different elements. Why is that, if both would have a similar migration pattern?

a said...

Yuri

FWIW- I think exotic X2e is found in Georgians/Southern Caucasus. I can't remember 100%- but it is also found in Altai regions.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180497/

Grey said...

@Mike Thomas

"Actually, the practice of exogamy is not underrated. In fact, it has well been recognized (at least hypothesized) long before genetic and isotopic studies."

I think the key thing here is the long distances mentioned, local exogamy is one thing but long distance could explain for example how those Iberian clades of mtdna H could spread so far from Iberia.

The second question it throws up is if this long-distance exogamy existed was it common or was it only elites i.e. princesses, or was this long distance exogamy actually long distance *endogamy* i.e. a trader/artisan population settled in small groups at the main nodes of the trade network and swapping brides long distance between themselves (combined with some amount of local exogamy with the majority population at each node for alliance building purposes).

#

"3) the first study actually suggests it was a bi-directional process. Ie there was a life-cycle mobility"

The back and forth of the Danish girl is what makes me wonder if she was part of a trader group.

#

"4) The second suggests a massive influx of *women*. Aren't the changes see in LN Europe thought to be (predominantly) due to invading steppic men ?"

Or it was small numbers of women at a time but over a long time period or women who for some reason had a significantly higher TFR.

#

(In the regions of Europe with very high levels of LP there won't be any correlations with any ydna or mtdna haplogroups because it is too ubiquitous but in regions with lower levels of LP there might be one or more haplogroup correlations.)

capra internetensis said...

@Nirjhar

That's a really cool find. The surprising thing is not so much finding some iron objects - they turn up here and there in the Bronze Age - but how far south it is at that period.

The reporting is typically sensationalist - this doesn't actually push back the Iron Age, because that is not defined by *any* production of iron, but by large scale production. Iron was smelted for a thousand years before the Iron Age really got started. (I assume this is smelted rather than native iron.)

And they are trying for aDNA! - really hope they get some.

Grey said...

Forgot a bit

" Aren't the changes see in LN Europe thought to be (predominantly) due to invading steppic men ?"

There was a paper (forgot the name) which talked about certain clades of mtdna H going up in central and eastern Europe which seemed like it might be an independent process from the big population movements.

Nirjhar007 said...

Capra, Yes but they are hunting for more and it seems Iron Deposits have Higher Concentration is South than North-
http://www.portal.gsi.gov.in/portal/page?_pageid=127,697649&_dad=portal&_schema=PORTAL
i suspect maybe the metallurgist came from North though the reverse is also probable.
a, i'm intrigued why the same pattern:)?

Krefter said...

Maybe the Bronze age is why when we only had ancient mtDNA and Y DNA, people couldn't find continuum with any Pre-Historic and modern Europeans. We know the reason continuum in Y DNA couldn't be found is because of Bronze age Mega-Founder lineages(which people at first assumed were Paleolithic lineages). Maybe the reason continuum in mtDNA couldn't be found is for an opposite reason; modern Euro mtDNA is a mosaic of Bronze age women from all over the continent. Trade and foreign affairs could have been very advanced back then.

Chad Rohlfsen said...

This is interesting!!

http://biorxiv.org/content/biorxiv/early/2015/05/26/018929.full.pdf

Davidski said...

Yeah, you mean this...

"A Chronological Atlas of Natural Selection in the Human Genome during the Past Half-million Years"

http://biorxiv.org/content/early/2015/05/26/018929

They should have included the samples from LN/EBA Europe.

Chad Rohlfsen said...

Yes, they should've.

Krefter said...

Does anyone know if the DNA file of the Mesolithic individual from Stora Karlsö Island is available online? It's not SF11.

http://uu.diva-portal.org/smash/get/diva2:645462/FULLTEXT01.pdf

"We used the Illumina HiSeq platform to obtain a total of 2,250,928 sequences
that could be confidently aligned to the human genome, and found strongly
elevated levels of C→T and G→A mismatches indicative of post-mortem
nucleotide misincorporations (Briggs et al. 2007). To assess whether there in
addition to endogenous DNA was evidence of modern-day contamination,
we exploited the approximately 12-fold coverage of the mitochondrial genome
to estimate contamination (Krause et al. 2010a), and found that all 61
informative sequences were consistent with the consensus, which yields a
point estimate of 0.0% modern contamination."

Helgenes50 said...

David,

Can you please, post the Ajv' results, for SteppeK10 and for TealK9