Genome of the Irish Bronze Age migration.

slowburner

Really interesting paper (2015) with some startling revelations.
http://www.pnas.org/content/113/2/368.short

slowburner

This paper raises questions about the nature of the Mesolithic genome, and how it might contrast with the Ballynahatty material. It seems to be largely glossed over in this paper...or did I miss something?

markesmith

Theory seems to be coming around to a Bronze Age replacement of the Neolithic megalith-builders by a proto Indo-European population, speaking a very archaic form of Gaelic.

Would I be right in saying this? Is there much continuity from Neolithic to early Bronze Age?

Cianmcliam

From what I can gather Neolithic houses fall off a cliff-edge right at the peak of the passage tomb phase, circa 3,200-3,000BC. Tomb building also sees a gap before wedge tombs, stone circles and stone rows start to appear. Recently there's been a re-examination of this 'quiet period' and it seems timber circles were being built during this time, to be replaced by circles of stone as the Bronze Age picks up pace.

I think it's nearly two decades since Jared Diamond proposed the rapid spread of proto-indo European languages in the Bronze Age due to the spread of tribes on domestic horses coming from the Eurasian Steppes. It could turn out to be correct, but the implications of large scale prehistoric conquests can be an unpopular line of inquiry.

Ipso

It's always good to look at what was happening Europe wide to get a idea of the big picture. I'm not sure about the exact nature of the population replacement but it does look like there was at least an elite/male dominated replacement, first entering Europe with the Yamnaya culture and then spreading to the isles with the bell beakers.
Regarding language, I have read a couple of ideas that include some form of archaic or pre celtic arriving or that celtic may be an off shoot from some form of generic "North West Indo European" that developed after encountering Germanic languages.
Other factors that might impact the overall genome difference might include the population size of the early population.

Was it Jared Diamond that proposed this? I know it was around for a while (along with an Anatolian homeland idea), David Anthony's book The Horse and the Wheel is meant to be a great source on the subject.

http://eurogenes.blogspot.com/2013/12/ancient-human-genomes-suggest-three.html
http://eurogenes.blogspot.com/2015/12/ancient-genomes-from-ireland-point-to.html

Cianmcliam

From what I remember, Diamond rejects Anatolia as a homeland for proto-indo European, as it had words for snow and mouse that echo through Indo-European areas. He places the invasions as being before 'Celtic' times as there were no words for chariots or any prehistoric inventions later than the wheel. He suspects horseback herding warriors because their language seems to have had few words for crops, they adopted the local words as they moved through the continents.

I think it's plausible, an earlier example of the rapid expansion of herding tribesmen like the Mongols or the Umayyad conquests across North Africa and south west Europe.

As far as I know, Renfrew's Anatolian homeland for Proto-Indo European was the dominant theory of the time.

markesmith

Doesn't this represent a major shift away from the "pots, not people" theory? I mean, are we talking about an invasion of an elite into Ireland in the early Bronze Age?

I'm presuming this gives more credence to the idea of the Celtic languages developing as a result of the Atlantic Bronze Age trading networks.

Either way, this is a major development in our understanding of Irish pre-history.

Cianmcliam

Well there's still significant problems with the theory of invasions from the steppe. Europe was still very heavily forested at the time so would not be ideal for large scale herding moving across the continent. As with the Mongols and other amorphous groups of tribes they face huge problems maintaining control over areas they conquer and usually end up sub-contracting this out to local warlords and chiefdoms in return for loyalty, tax and deference.

dubhthach

All modern Europeans can be modelled as basic level as varying admixtures of at least three ancestral populations these been:

WHG -- Western Hunter Gather -- modal in remains dated to European Paelothic/Mesolithic
EEF -- Early European Farmer -- appears in Neolithic, oldest sampling from western Turkey/Agean basin
ANE -- Ancient Northeast Eurasian -- extinct "meta-population" -- oldest sample in Siberian Paelothic (M'alta boy 25k years before present)


All modern populations in Europe have various levels of these when you run an admixture analysis. What ancient DNA has allowed us do is figure out the arrival of these various components plus to certain extent their vector of movement.

The oldest genomes from across Europe are dominated by WHG, the oldest example we have is upper Paleolithic remains from Bichon in Switzerland which is dated to 13,300 ybp.

What seems to have happened is EEF expanded into Europe becoming dominant component in population of Neolithic farmers, a the Neolithic went on you see an increase in WHG in remains. What this seems to imply is that admixture went on from remaining Hunter-Gather groups into Neolithic farmers, so that by late Neolithic that farmer populations had increased level of WHG ancestry. This is evident in the Ballynahatty woman who while falling within the EEF cluster by and large has increased levels of WHG ancestry compared to Neolithic farming samples from the continent.

What the Neolithic samples lack is ANE, what we see is that sampling from Yamnaya remains from Russia (near Volga) contain ANE, and that Corded Ware and Bell Beaker samples from Central Europe show ANE input coming from Yamnaya (they have lower levels of ANE as they mixed with Neolithic farming population).

In case of Bronze age samples from Rathlin island these have higher ANE levels than modern Irish population, what's basically happened is that over the last 4,000 years ye've had a "blender" effect where everyone has basically gotten some level of the three components. A modern parallel would be to look at modern Latin-American populations (for example Brazilians and Mexicans) who have undergone three way admixture in last 400-500 years.

Recently at same time as Bichon remains were sequenced we got the first sequencing of remains from the Causcus these been Mesolithic and later. What these have shown is that there was a distinct Hunter-Gather population in the region which spilt from WHG about 45k years ago. This population contributed DNA into what would later be Yamnaya.

http://www.nature.com/articles/ncomms9912



What we are probably seeing is gradual expansion of steppe like ancestry over several centuries, with Bell Beaker been potentially the vector for it in western Europe.

With regards to what language the Rathlin men spoke, I'd imagine time wise it probable pre-dates Proto-Celtic, however if it was some form of Western Proto-IE this has implications for later spread of Proto-Celtic in western Europe.

For example it's lot easier for the changes that mark Proto-Celtic from Proto-IE to spread when it's matter of "dialect change" due to contact among "dialects" that are already closely related (as oppose to shifting from a non-IE language to Proto-Celtic), people have argued that a potentially non-Celtic language survived in Ireland until at least the 6th century AD. This situation might be akin to fact that in Iberia you had both Celtic languages (Celtiberian and Gallaecian) and non-Celtic Indo-European languages (Lusitanian -- it isn't Celtic as it retains Proto-IE /p/ which is deleted in Proto-Celtic).

Of course what's going to happen over the next 10 years is sequencing prices will continue to fall (off a cliff), so eventually we'll basically end up with aDNA full genomes from every well perserved speciman. The amount of data this will produce will give us alot better idea with regards to ancient population structure/history.

So far we have four genomes from Ireland, one from Neolithic (Ballynahatty) and three Rathlin men from Early Bronze age. Bradley's lab supposedly has another 47 or so genomes to publish which supposeldy cover "every historic period of Ireland"

Good work been done in UCD as well, see following research:
https://www.ucd.ie/archaeology/research/phd/daniel_fernandes/

Population variation following the Neolithic revolution: assessing the palaeogenetics of southern Europeans throughout the Neolithic

PhD Candidate: Daniel Fernandes
Supervisor: Professor Ron Pinhasi
Funded By: Irish Research Council Government of Ireland Postgraduate Scholarship

Abstract

The evolution of human societies has been shaped by successive migration waves. One of the most important was the Neolithic expansion of farming societies, spreading culture and genes from the Fertile Crescent into the rest of Eurasia. This set the end of hunter-gatherer cultures and, although there is a debate on whether this happened by active replacement or cultural diffusion, it is evident that the genetic background of European populations changed substantially after the Neolithic expansion (Pinhasi et al., 2012). Southern Europe seems to have played a very important role in the Neolithic period as its people might have migrated and expanded to the rest of Europe (Skoglund et al., 2012). This project will apply Next Generation Sequencing (NGS) methods to the analysis of human ancient DNA (aDNA) of Neolithic southern European skeletal samples with the aim to shed light on their genetic variation over time. A particular focus is placed on revealing which part of the Neolithic and which particular geographic region in southern Europe made the most substantial genetic contribution to present day European genetic diversity by comparing the obtained aDNA to available genomic scale reference data. Another focus will be the assessment of dispersal and admixture patterns between southern European and the ancient European samples currently analysed as part of Pinhasi’s ERC project. The genetic markers analysed will include full mitochondrial genomes, Single Nucleotide Polymorphism (SNPs) and the targeting of specific genes associated with pigmentation, digestion, and lactase tolerance. With this project, we hope we will be able to increase the amount of information available on the population dynamics of the Neolithic period and the impact they had on modern-day European genomic diversity.

I should note that Lactose tolerance appears to come into Europe with Steppe input, this gave an evolutionary advantage to those carry it (ability to digest Milk as an adult) to such an extent that it's now nearly "fixed" in modern European populations (eg. Lactose tolerance is the norm)