DNA findings challenge the idea of Celtic populations

slowburner

New research indicates that the idea of a Celtic race in Britain is at the very least, a misnomer and that the Britons were not eradicated by an incoming Saxon population.
Probably even more interesting is the demonstration of 'significant pre-Roman but post Mesolithic movement into southeast England from continental Europe'.
That's a pretty broad timescale but surely reflects what we already know about Bronze Age populations?

BBC article
Original paper

robp

slowburner wrote: »

New research indicates that the idea of a Celtic race in Britain is at the very least, a misnomer and that the Britons were not eradicated by an incoming Saxon population.
Probably even more interesting is the demonstration of 'significant pre-Roman but post Mesolithic movement into southeast England from continental Europe'.
That's a pretty broad timescale but surely reflects what we already know about Bronze Age populations?

The fine scale boundaries they found are fascinating but I am not surprised they failed to found one Celtic type. I would have thought that was expected as Celtic languages in Scotland have a very different history than Celtic languages in Wales or Cornwall.

Ipso

Well prior to the arrival of the Romans people in Britain spoke celtic languages, and as the term is more of a linguistic and broad cultural one then they were celts.
I think the notion of a celtic race, implying some kind of identical monolithic group of people needs to be done away with.

dubhthach

I have my concerns about this namely

• Methodology, they used modern populations to compare derived clusters
• Press and DNA do not mix!

If you look at the PDF of report they show the surronding European clusters and then derive what percentage each cluster in Britain "inherits" from these clusters. The problem I see with this is that all of this is based on modern DNA. It doesn't use any ancient-DNA as a baseline so as a result thins such as Admixture and genetic drift come into play. I don't think their model is robust enough to cover admixture.

So for example if parts two ancestral clusters merge you end up with a new third cluster. What's evident looking at their map is that some of clusters appear to be due to level of admixture varying due to advance of Anglo-Saxon language across Britain during the period 400-800AD. The difference between Devon and Cornwall is telling, given that Cornwall retained a Celtic language until the 18th century whereas it had disapearred from Devon by probably the 7th-8th century.

Secondaly the media keep talking about "Genes" and that there is some concept of a magical "Celtic Gene", which is absolute rubbish, first off the study looked at SNP's not anything as massive or complex as a gene. Secondly the concept of "one single gene" to rule them all is ridiculous typical media crap. What's also important to point out that this is an Autosomnal study, it looks at the non-sex linked nuclear DNA. This recombines each generation, if however we look at the male lineages (Y-Chromosome) we can clearly see a gradient from West to East when it comes to male lineages. (see Busby, Royal Society)

Anyways the Ancient DNA will be key, the crowd behind this (Welcome trust -- whose interest is actually medical applications of DNA and not genealogy/history) discovered 5 bodies when building a new facility in Hinxton in eastern England. It turns out 2 of the bodies are Iron age (and male) whereas the other 3 were of Anglo-Saxon period (and female). Ancient DNA was retrieved from all 5 (in one case a very high covereage sample was recovered). These are the first aDNA samples recovered from Britain. What's interesting is the Iron age ones cluster more with modern Irish/Western Scots then they do with modern English.

dubhthach

Of course the key people doing Ancient DNA research today are at the Reich lab in Havard. They just published a paper looking at Indo-European migration using close on 100 ancient DNA samples from across Europe (covereing the mesolithic to Bronze ages). This paper has first DNA recovered from Yamnaya Culture of Eurasian steppe (in this case recovered from Kurgan's near the Volga river)

http://genetics.med.harvard.edu/reich/Reich_Lab/Welcome.html

"Massive migration from the steppe was a source for Indo-European languages in Europe" (Nature 2015)

We generated genome-wide data from 69 Europeans who lived between 8,000–3,000 years ago by enriching ancient DNA libraries for a target set of almost 400,000 polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies1, 2, 3, 4, 5, 6, 7, 8 and to obtain new insights about the past. We show that the populations of Western and Far Eastern Europe followed opposite trajectories between 8,000–5,000 years ago. At the beginning of the Neolithic period in Europe, ~8,000–7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a ~24,000-year-old Siberian6. By ~6,000–5,000 years ago, farmers throughout much of Europe had more hunter-gatherer ancestry than their predecessors, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but also from a population of Near Eastern ancestry. Western and Eastern Europe came into contact ~4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced ~75% of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least ~3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for a steppe origin9 of at least some of the Indo-European languages of Europe.

Full paper here:
http://genetics.med.harvard.edu/reich/Reich_Lab/Welcome_files/nature14317.pdf

"Ancient human genomes suggest three ancestral populations for present-day Europeans" (Nature 2014)

We sequenced the genomes of a ~7,000-year-old farmer from Germany and eight ~8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes1, 2, 3, 4 with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians3, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations’ deep relationships and show that early European farmers had ~44% ancestry from a ‘basal Eurasian’ population that split before the diversification of other non-African lineages.

Full paper here:
http://genetics.med.harvard.edu/reich/Reich_Lab/Welcome_files/2014_Nature_Lazaridis_EuropeThreeAncestries_1.pdf

The Reich Lab are basically leaders in the field at the moment and are in process of amazing one of largest collections of Ancient DNA which is been used to analyse modern DNA samples.

slowburner

Thanks for this Dubhtach. Good to see the other side of the coin.

cfuserkildare

My concern would have to be, How misleading would a DNA sample from for example a 2nd or 3rd generation imigrant have on the findings?

Can the company involved guarentee that the samples taken would be from fairly pure family lines that go back far enough?

Friends from Poland/Lithuania/Caribean/Nigeria/Asia etc who's families have only been here since WW2 for example would not give us a true idea of where our Celtic ancestors were located and even more interestingly where they came from.

Remembering also that the Celts were Immigrants once also.

dubhthach

Well this report comes from the "People of the British Isles" Project (In their definition the "British Isles" end at the border ). To be part of the project you had to have all four grandparents from a specific area, generally rural. The idea was to get an image of Britain in late 19th/early 20th century. The emphasis on rural was as much about reducing impact of migration to urban areas etc.

So at best we are looking at an image of how rural Britain looked like 2-3 generations ago.

There's a similiar project going on here, but they are even more stringent they want you to show proven records that all 8 great-grandparents are from one geographical regions (defined as an area about 60km's across etc.), of course that's part of reason why they are having trouble getting people to volunteer, for example I couldn't take part as of my 8 great-grandparents 6 were from South Galway/North Clare however the other 2 were from Belfast and Liverpool (Liverpool Irish).

'Dienekes' has some analysis on his blog:
http://dienekes.blogspot.ie/2015/03/british-origins-leslie-et-al-2015.html

Again without ancient DNA (such as a the Hinxton Iron age genomes) than all we can say is that British population had the following genetic clusters 3 generations ago. What seems to be mixed in media is that all of these clusters are generally related to each other. More so than if you were to compare them with a bunch of Spanish or Italian samples.

dubhthach

slowburner wrote: »

Probably even more interesting is the demonstration of 'significant pre-Roman but post Mesolithic movement into southeast England from continental Europe'.
That's a pretty broad timescale but surely reflects what we already know about Bronze Age populations?

Just noticing this bit, you should read the paper regarding European populations been made up of three ancestoral populations. The Ancient-DNA is showing the following:

• Mesolithic component
• Neolithic component
• Copper/Bronze age component

In this case these are been termed "Western Hunter Gather" (WHG), "Early European Farmer" (EEF) and "Ancient North Eurasian" (ANE). Every modern European's genome is made up of various "blends" of these three components. They developed the following admixture model using the ancient DNA as baseline and comparing it against circa 2,400 modern samples:



On this diagram:

MA1 = 25,000 year old boy from Siberia, belongs to "extinct" meta-population known as "Ancient North-Eurasian" (extinct as in no longer a distinct population, all European's and Native Americans however carry DNA from this population)

Loschbour: Mesolithic Hunter-Gather from Luxembourg (circa 8,000 years old)

Stuttgart: Neolithic Early Famer from Stuttgart (circa 7,000 years old)

To give a modern comparison, using my 23andme sample my genome would be comprise:

WHG: 43.24%
Near_Eastern: 39.529% (proxy for EEF)
ANE: 15.28%
South_Eurasian 1.945%

In other words like most North-Western European a plurality of my genomes comes from Mesolithic hunter gatherers, however the arrival of argiculture obviously contributed heavily as did the arrival of ANE (which some are linking to spread of Indo-European languages, of which Celtic is a branch of)

Kinda mind bending to think that nearly 1/6th of my genomes is more in common with that of genome of a boy who died near Lake Baikal 25,000 years ago than it is to a Mesolithic Hunter/gatherer who died in modern day Luxembourg circa 8,000 years ago.

cfuserkildare

Hey dubhthach,


Yes I was wondering about that.

As an example, in my family about 5 generations ago we had a great great etc grandparent came from Ireland to Scotland and worked like a lot of Irish, up the west coast from Liverpool to Ayr.
Their children settled for I think 2 generations then headed East to my home town.
However, we know that a lot of our ancestry went to Ireland in the 14th century when the Bruce's were chasing English landlords around.
So our ancestry may have gone kinda full circle as it were, but how would this reflect on a DNA ancestry trace?

dubhthach

Well what's important to remember with Autsomnal DNA (which PoBI study looked at / also what 23andme and ancestrydna test) is that each generation they undergo recombination.

To give an example my Otherhalf is from the Philippines, her great-grandfather was Spanish, so you'd expect perhaps about 10-12% of her genome would show up with European influence. (which is the case looking at 23andme sample), now if she had hooked up with a Filipino instead of me any children they would have had would have had at most 6% Euro ancestry when it comes to Autosomnal, likewise the next generation it would reduce again.

The only way for a "ancestral component" to maintain a certain percentage in a population when there's a big enough influx that eventually through intermarriage everybody in population carries a chunk of that ancestral population in their autosomes. This way you reach an equilibrium.

Now if however you are talking about "migration" of only one or two people who marry locally eventually over time (several centuries) if the line continues the process of marrying locals than they won't appear hugely distinctive from local population they married into.

Where you might see differentiation is on for example male lineages (the Y doesn't recombine, so passes down from father to son).

dubhthach

As an aside I got a complimentary test with AncestryDNA, this is an autosomal product (Eg. looking at the non-sex linked chromosomes), they seem to have updated their "ethnicity profiles" here's my results (posted last night)

slowburner

Some interesting material here:
http://www.eupedia.com/genetics/britain_ireland_dna.shtml

dubhthach

I'd caution about Eupedia at times.

What's more interesting is recent study looking at 10 ancient DNA samples from England, first ancient DNA full genomes published from Britain. 3 were Iron age, 7 from Anglo-Saxon era.

see:
http://biorxiv.org/content/early/2015/07/17/022723

Abstract

British population history has been shaped by a series of immigrations and internal movements, including the early Anglo-Saxon migrations following the breakdown of the Roman administration after 410CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences generated from ten ancient individuals found in archaeological excavations close to Cambridge in the East of England, ranging from 2,300 until 1,200 years before present (Iron Age to Anglo-Saxon period). We use present-day genetic data to characterize the relationship of these ancient individuals to contemporary British and other European populations. By analyzing the distribution of shared rare variants across ancient and modern individuals, we find that today’s British are more similar to the Iron Age individuals than to most of the Anglo-Saxon individuals, and estimate that the contemporary East English population derives 30% of its ancestry from Anglo-Saxon migrations, with a lower fraction in Wales and Scotland. We gain further insight with a new method, rarecoal, which fits a demographic model to the distribution of shared rare variants across a large number of samples, enabling fine scale analysis of subtle genetic differences and yielding explicit estimates of population sizes and split times. Using rarecoal we find that the ancestors of the Anglo-Saxon samples are closest to modern Danish and Dutch populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.

Full paper here:
http://biorxiv.org/content/biorxiv/early/2015/07/17/022723.full.pdf

Razib Khan posted a blogpost about this, can be read here:
http://www.unz.com/gnxp/between-the-millennia-and-generations/

Interesting bit:

There is still much that needs to be worked out on this topic. There’s only so much you can say from these handful of individuals. But even with these finite samples much was extracted. The authors observe that one of their Anglo-Saxon era individuals, buried in an Anglo-Saxon fashion, clustered perfectly with the British Iron Age individuals. Additionally, this individual was outfitted in a manner which suggested they were very high status within Anglo-Saxon society. But the authors did not connect this with the fact that all their Anglo-Saxon individuals were female. Hypergamy is entirely typical in human societies, and it is plausible that large numbers of migrating German men arrived on British shores without a wife and family in tow. In the years after the Norman invasion it was not uncommon for noble Saxon houses to give their daughters to an invader. And so the Anglo-Norman aristocracy arose as a synthesis between distinct paternal and maternal lineages. A similar scenario likely played out during the invasions of the Dark Ages.

The first two Iron age samples from Hinxton were released into public domain a while ago, some of people running analysis state that in run's that they tend to cluster with modern Irish population samples (The Hinxton remains date to 1st century BC)

dubhthach

Anyways what we really need is some ancient DNA from Ireland. I see the "Genetic Genealogy Ireland 2015" (held in RDS) speakers have been announced. Dr. Dan Bradley of TCD (he of the Uí Néill study -- 2006) is giving a talk labeled:

"The best bones, ancient genomics & transitions in European prehistory"

Also Professor James Mallory (Queens), who authored "The origins of the Irish" (interesting but not fully up todate on some of DNA) is also giving a talk at it.

http://ggi2013.blogspot.ie/

There's a huge amount of remains that were discovered during digs during the boom, even remains from early medieval period would be interesting to sequence as they give a baseline at a particular point in time which can be used to compare modern population with.