The Irish DNA Atlas: Revealing Fine-Scale Population Structure and History within Ireland

[Grace O'Malley]

The extent of population structure within Ireland is largely unknown, as is the impact of historical migrations. Here we illustrate fine-scale genetic structure across Ireland that follows geographic boundaries and present evidence of admixture events into Ireland. Utilising the ‘Irish DNA Atlas’, a cohort (n = 194) of Irish individuals with four generations of ancestry linked to specific regions in Ireland, in combination with 2,039 individuals from the Peoples of the British Isles dataset, we show that the Irish population can be divided in 10 distinct geographically stratified genetic clusters; seven of ‘Gaelic’ Irish ancestry, and three of shared Irish-British ancestry. In addition we observe a major genetic barrier to the north of Ireland in Ulster. Using a reference of 6,760 European individuals and two ancient Irish genomes, we demonstrate high levels of North-West French-like and West Norwegian-like ancestry within Ireland. We show that that our ‘Gaelic’ Irish clusters present homogenous levels of ancient Irish ancestries. We additionally detect admixture events that provide evidence of Norse-Viking gene flow into Ireland, and reflect the Ulster Plantations. Our work informs both on Irish history, as well as the study of Mendelian and complex disease genetics involving populations of Irish ancestry.

https://www.nature.com/articles/s41598-017-17124-4

[Grace O'Malley]

And this one as well.

Insular Celtic population structure and genomic footprints of migration

Previous studies of the genetic landscape of Ireland have suggested homogeneity, with
population substructure undetectable using single-marker methods. Here we have
harnessed the haplotype-based method fineSTRUCTURE in an Irish genome-wide SNP
dataset, identifying 23 discrete genetic clusters which segregate with geographical
provenance. Cluster diversity is pronounced in the west of Ireland but reduced in the east
where older structure has been eroded by historical migrations. Accordingly, when
populations from the neighbouring island of Britain are included, a west-east cline of CelticBritish
ancestry is revealed along with a particularly striking correlation between haplotypes
and geography across both islands. A strong relationship is revealed between subsets of
Northern Irish and Scottish populations, where discordant genetic and geographic affinities
reflect major migrations in recent centuries. Additionally, Irish genetic proximity of all Scottish
samples likely reflects older strata of communication across the narrowest inter-island
crossing. Using GLOBETROTTER we detected Irish admixture signals from Britain and
Europe and estimated dates for events consistent with the historical migrations of the NorseVikings,
the Anglo-Normans and the British Plantations. The influence of the former is
greater than previously estimated from Y chromosome haplotypes. In all, we paint a new
picture of the genetic landscape of Ireland, revealing structure which should be considered in
the design of studies examining rare genetic variation and its association with traits.

https://www.biorxiv.org/content/biorxiv/early/2017/12/08/230797.full.pdf

[Fractal]

Irish Americans = John F. Kennedy, Ted Kennedy, Bill O'Reilly, Sean Hannity, etc

Great contributions to the USA.

[Grace O'Malley]

Co-author Michael Merrigan, of the GSI, said the study challenges the accepted narratives on the origins of the people of Ireland.

“We now get a clearer, scientifically-based map of the distribution and settlement of our ancestral groups across the island of Ireland,” he said. “Historians and students of medieval Ireland have now a wonderful resource on the movements and inter-relationships of our ancestor groups through their DNA.”

He said the study will open up new research opportunities for many disciplines, especially those researching Irish medieval genealogies and the history of Irish clans.

It also reveals relatively high levels of Northwest French (probably Celtic) and Norwegian-like (probably Viking) ancestry in Ireland.

http://www.irishexaminer.com/ireland/irelands-dna-revealed-by-region-464207.html

[Grace O'Malley]

http://i64.tinypic.com/33a8fvc.jpg

http://i66.tinypic.com/2wo8x6o.jpg

[Graham]

https://media.springernature.com/lw900/springer-static/image/art%3A10.1038%2Fs41598-017-17124-4/MediaObjects/41598_2017_17124_Fig1_HTML.jpg

[Graham]

..]

Makes sense on the pca i guess. Just quickly bordering the countries. Though cornwall and orkney could fit in their own bubble with a little more identity too/.

largest population and massive majority of Scotland is in SSC(NICS).

https://scontent-cdt1-1.xx.fbcdn.net/v/t34.0-12/24989453_10155956137495421_475909465_n.png?oh=0833 16f2de1f39557865462ea9d2c7f7&oe=5A2D31EE

[Grace O'Malley]

Admixture info Norse and Plantations.

http://i66.tinypic.com/25illzo.jpg

[Grace O'Malley]

Connacht and Dublin are close on that dendrogram. Not sure why that would be the case.

[Grace O'Malley]

https://media.springernature.com/lw900/springer-static/image/art%3A10.1038%2Fs41598-017-17124-4/MediaObjects/41598_2017_17124_Fig1_HTML.jpg

This dendrogram shows why Irish get Orcadian so often in Gedmatch.

[Graham]

Irish, Scots & Welsh show higher French than the English.
Irish & Scots have more Norwegian than the Welsh or English.
England has more German & Danish.


https://scontent-cdt1-1.xx.fbcdn.net/v/t35.0-12/25198513_10155957244770421_1888493420_o.png?oh=c43 9a02016ebe196f666fd7ba12d7e12&oe=5A2F1357


A striking result of our admixture analysis is the surprising amount of Norwegian-like ancestry in our Irish clusters. We also detected high levels of Norwegian ancestry in Orcadian and Scottish clusters, and relatively low Norwegian ancestry in English and Welsh clusters. The Norwegian clusters that contribute significant ancestry to any Irish or British clusters predominantly consist of individuals from counties on the north or western coasts of Norway.

These areas are noted to be regions where Norse Viking activity originated from.

Whilst this surprising Norwegian signal in Ireland is most likely due to Norwegian admixture into Ireland, indeed this would corroborate with accounts of Irish slave trade in the Viking era.


To test this hypothesis we ran an additional regression admixture analysis, this time modelling Norwegian haplotypes as a mixture of Irish, British, or European haplotypes (Supplementary Data 6). We observe significant proportions of Irish, Scottish, and Orcadian ancestry in modern Norway (6.82%, 2.29%, and 2.13%, respectively), particularly western Norway. This could provide evidence for Irish admixture back into Norway, but could also easily be explained by Norwegian haplotypes existing in Ireland, Scotland, and Orkney. Therefore, we are able to provide an upper estimate of ~20% Norwegian ancestry within Ireland, but unable to provide an empirical lower limit.

[Sikeliot]

Looks like Connacht, Dublin, and Leinster have the most affinity to Britain, while Ulster (Gaelic, not Planters) and South Munster have the least.

[Graham]

Looks like Connacht, Dublin, and Leinster have the most affinity to Britain, while Ulster (Gaelic, not Planters) and South Munster have the least.

Ulster pre plantation i read somewhere or heard was irelands most gaelic spoken area, the O'Neils were a strong clan in Ireland and owe much to the Islands influence. Donegal, a nearly cut off county is a gaelic area in culture still.

Gaeltacht

https://upload.wikimedia.org/wikipedia/commons/thumb/3/34/Gaeltachtai_le_hainmneacha2.svg/1200px-Gaeltachtai_le_hainmneacha2.svg.pnghttps://www.irishorigenes.com/sites/default/files/field/image/Figure%203%20(Prominent%20Gallowglass%20and%20Scot s%20Clans).jpg

[Neon Knight]

The extent of population structure within Ireland is largely unknown, as is the impact of historical migrations. Here we illustrate fine-scale genetic structure across Ireland that follows geographic boundaries and present evidence of admixture events into Ireland.

What do you think of this finding?


The team did compare the modern group with two ancient genomes from Ireland. One came from a person who lived near Belfast during the Neolithic, around 5,000 years ago. The other was from a person who lived on Rathlin Island in the late Bronze Age, from 2000 to 1500 B.C. The scientists were hopeful they’d find genetic affinity, or relatedness, between the Bronze Age genome and modern inhabitants of the region where those bones had been found. No dice. The ancient genomes mainly served as a nice background reference to highlight variances between the modern groups.

https://news.nationalgeographic.com/2017/12/irish-ancestry-dna-map-ireland-vikings-genetics-science/

[Profileid]

This dendrogram shows why Irish get Orcadian so often in Gedmatch.

I always wondered about that in particular. That's often my top match on various calcs

[Grace O'Malley]

Adding this especially for Graham.

There is a new paper coming out shortly about Scotland and the islands by Ed Gilbert and the IDA team. Someone at a talk from Ed Gilbert said this:


Scotland and Ireland high in French like ancestry, low in German like with some Norwegian (which is not seen in the German like area). The German like area included the borders region.

Looking forward to this.

[Bosniensis]

Do you have I2 people in Ireland? If you do, those are Celts.

R1b people are Germanic, and related to Normans and other non-Celtic people.

Celts colonized Gaul, Spain and Britian from Balkans.

[Sikeliot]

Adding this especially for Graham.

There is a new paper coming out shortly about Scotland and the islands by Ed Gilbert and the IDA team. Someone at a talk from Ed Gilbert said this:



Looking forward to this.


Scots are halfway genetically between Ireland and England, no?

Though in reality all of them are close so these studies really nit-pick the differences. The English are closer genetically to Irish, even to people in remote places like Kerry, than to the Germans.

[Grace O'Malley]

Scots are halfway genetically between Ireland and England, no?

Though in reality all of them are close so these studies really nit-pick the differences. The English are closer genetically to Irish, even to people in remote places like Kerry, than to the Germans.

Depends on what part of Scotland. If populations are averaged it is in the middle but different areas are closer to the Irish i.e Western Scotland but other parts of Scotland are closer to the English. We all know the people from Britain and Ireland are closer to each other but some English are closer to the Southern Dutch and Belgian populations. Also all the Isles are closer to Scandinavian populations than they are to Germany.

[Sikeliot]

Depends on what part of Scotland. If populations are averaged it is in the middle but different areas are closer to the Irish i.e Western Scotland but other parts of Scotland are closer to the English. We all know the people from Britain and Ireland are closer to each other but some English are closer to the Southern Dutch and Belgian populations. Also all the Isles are closer to Scandinavian populations than they are to Germany.

So did we finally determine, which is the most native 'Irish' cluster -- SW Munster, or North Leinster/Ulster? The studies contradict one another, and themselves.

[Grace O'Malley]

So did we finally determine, which is the most native 'Irish' cluster -- SW Munster, or North Leinster/Ulster? The studies contradict one another, and themselves.

I think it is South Munster Sikeliot. Do you agree?

[Sikeliot]

I think it is South Munster Sikeliot. Do you agree?

Yes. I didn't see anything particularly 'isolate' about the North Leinster/Ulster cluster.

It looked to me like, as far as distance from Britain went, it looked like the closest was South Leinster and Wexford (places like Kilkenny, Wicklow, etc) > Central Leinster > Connacht and North Munster > North Leinster/Ulster but then it looked like South Munster and Cork were separated on the dendrogram from all the rest.

[Graham]

Adding this especially for Graham.

There is a new paper coming out shortly about Scotland and the islands by Ed Gilbert and the IDA team. Someone at a talk from Ed Gilbert said this:



Looking forward to this.

I bet when they said Borders they really meant from the east side south of Lammermuir or Pentland. A low population area, but it is culturally like England.

Where the west border historically was an historical battlefield of border reivers and many of those people have ties to Dumfries & Galloway and Northern Ireland.

Then you have the central belt. Populated mainly since the 18th century, could be a mix of sorts of Scots with Irish ancestry. So again could be like the Northern Irish in DNA.

Central Scotland to Tayside will be interesting, one to watch. I'd also like to see places in Sutherland & Caithness compared to Orkney

[Graham]

Kind of how i have it just now. So we will see as new data comes in. :)

https://image.ibb.co/cKi3K9/image.png

[RenaRyuguu]

bump