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View of Connemara Harbour

"We are merely the present-day custodians of our Ancestor's Genes."


Testing of Short Tandem Repeat markers (STRs) on the male Y chromosome is the commonly used tool available to genealogists.

Some are using this technique to investigate connections with others bearing the same surname and in this way are making contact with 4th, 5th and 6th cousins for the first time. If this is your aim, I strongly recommend joining your surname project as administrators there concentrate on grouping like results and finding recent connections.

Others are interested in the ancient origins of their cluster and this website looks at the origins and age of the R1b cluster called "Irish Type III", believed to be that of the Dál gCais sept that lived in the area of Ireland called Thomond.

If you have come across this website by chance, think you are "Irish Type III" and have not contacted me before, I may have been trying to contact you. Please go to the Lost Members Page. If your name appears there, please contact me.

For those that are new to Genetic Genealogy, as the use of DNA in genealogy is called, and believe they will find this discussion a little daunting, I suggest it may be worthwhile spending a little time with some basic reading:-

Is the Answer in your Genes? - Debbie Kennett - a succinct primer on DNA testing

Basic introduction to cells, chromosomes and DNA - Nancy Custer's excellent site

I have the results of my Genetic Testing, Now What? - Blaine T. Bettinger

ISOGG Wiki - A comprehensive Wiki with all you need to know concerning Genetic Genealogy.

Blair DNA 101 - A series of three pages, DNA101, DNA102, DNA103 to explain DNA in "Layman's Terms".



R1b is the most common haplogroup in Western Europe with especially high incidence in Spain, Portugal, Western France and Ireland. The modal, (or most commonly occurring haplotype), for this R1b of Western Europe is called the Atlantic Modal Haplotype, (AMH), Ysearch ID, XQJ7H. For more information on AMH see the Links page.

The first 25 markers of AMH in Ysearch format are:-

AMH - DYS Marker Values

Because of the large number of males that fall within this haplogroup, efforts have been made to find clusters that show differences in the Short Tandem Repeat,(STR), of their alleles from the AMH by looking for similar variations in the haplotypes.

What Haplogroup do I belong to?

Your testing company has probably already suggested the broad haplogroup that you belong to, and if you are reading this page, you probably already know you are part of the R1b population. If you are unsure of your haplogroup, try Jim Cullen's Haplogroup Predictor program. R1b-IrishIII is one of the possible predictions of Jim's program and if your markers predict this sub-clade at greater than 95%, then you are in all probability Irish Type III.

Defining Haplogroups - SNP testing

While isolating clusters of haplotypes that have similar allele variations gives a reasonable probability of the haplogroup, a Single Nucleotide Polymorphorism, or (SNP) mutation formally differentiates them, and it is only after SNP testing that you can be sure you are a member of that haplogroup. To learn more on SNPs see:- SNPMedia or Genetics 101 - What are SNPs?

A Y-DNA haplogroup is defined as all of the male descendants of the single person who first showed a particular SNP mutation. A SNP mutation identifies a group who share a common ancestor far back in time, since SNPs rarely mutate. Each member of a particular haplogroup has the same SNP mutation.

Within R1b, a series of SNPs have been discovered that divide this haplogroup and specific deep clade testing is required to identify which SNPs have occurred, are positive or 'derived'), in a DNA sample. At the current time little is known about the fraction of R1b these subclades define, nor what relationship they have with STR defined clusters, but this is changing. With the continuing discovery of each new defining SNP , so the nomenclature of the various clusters is changed. For a view of the "R-2017" tree and the SNP s that identify each branch, check out the ISOGG page.

One SNP, M269, which if positive, defines the R1b1a2 haplogroup - (was R1b1b2 and before that, R1b1c) and can be called R-M269. It has been estimated that perhaps 80% of R1b falls into this grouping. It can, however, be further divided into various "clusters".

R1b1a2 - R-M269 'Clusters'

Some clusters that have been identified by STR variations include Scots, Frisian, North West Irish and South Irish, denoting the geographical area that is ancestral for present day holders of similar haplotypes. The genotyping companies are now offering SNP testing and results are coming in that are helping to relate the STR groupings to SNP markers. For instance, M222+ is carried by those that are in the NW Irish haplogroup and is presently called R-M222. As the name suggests, this group has its ancestral home in the far North West counties of Ireland.

The Irish Type III cluster

In April 2006, researcher Dr Ken Nordtvedt, identified another small grouping where the ancestral geographical area appeared to be predominately Irish, but the haplogroup was quite different from NWIrish and South Irish. As the third STR defined Irish grouping, it has been given the name 'Irish Type III' and its distinctive markers where it differs from AMH are:

Irish Type III
DYS 439 = 11
DYS 459 = 8-9
DYS 464 = 13-13-15-17
DYS 456 = 15
DYS 557 = 15
DYS 716 = 24
DYS 533 = 13
DYS 636 = 12
DYS 463 = 25

Some variation from these values can and does occur but two that almost always have the modal values are DYS459 = 8,9 and DYS463 = 25. It should be noted that Ysearch database has (at 1 March 2010) been brought into line with FTDNA and Ancestry. NO LONGER does two (2) need to be subtracted from the FTDNA and Ancestry DYS463 result before posting to Ysearch. Reference: FTDNA email 27 February 2010.

If you have tested at DNA Heritage or Relative Genetics in the past, then you will need to add two (+2) to DYS463 before entering at Ysearch. For further help in adjusting your markers, see Convert Markers.

Testing of DYS463 forms part of DNA-Heritage and Relative Genetics 43 marker test and the now defunct Ancestry 30 STR marker test and is available from FTDNA in the extended 111 STR marker test. It used to be recommended that this marker be tested to confirm membership of the Irish Type III cluster. However, testing the SNP L226 is now cheap and is readily available as a superior confirmatory test. Searches have been conducted in the Ysearch and other STR databases, and 1,225 haplotypes have now been found which relate to this grouping; 1,133 within a Genetic Distance, GD, of 8 to the modal on 37 markers, together with a further 92 ´Outliers´ (those that a part of the cluster but are some distance from the modal). A record with the name "Modal R1b Irish Type III" and ID, NT4BZ, has been set up in Ysearch database, to assist others in searching for similar haplotypes and a 'minimum markers' ID has also been set up as WXEWM. Setting a Genetic Distance of 1 will display the majority of Irish Type III haplotypes in the database. This spreadsheet shows all 1,012 Irish Type III haplotypes presently identified from FTDNA projects and the Ysearch and Ybase public databases. Some are interested in the spread of alleles at each marker and these can be viewed on this spreadsheet.

Where does 'Irish Type III' originate?

Looking at the ancestral geographical area for this grouping, of those who do not state 'USA' or 'Unknown', 85.6% participants state 'Ireland'. Presently this is 446 of the 1,225 haplotypes, however many surnames with 'Unknown', or a state of the USA are obviously Irish in origin, O´Brien, Casey, Hogan etc. and if/when known would increase the Irish percentage even more. The counties that are stated record:-


To see a Map of these Counties Click Here

Of the others who state an ancestral origin, 5.0% give ´Scotland´, 7.3% give ´England´ and 3 haplotypes give ´Wales´, an eight haplotypes from Europe, possibly "Wild Geese", the name given to Irish exiles to the Continent in the 17th and 18th centuries. A Dalcassian (Dál gCais) Signature? It has now been shown that this clade is that of the Dalcassian clans of Clare, Limerick and Tipperary, the principal family of whom are the O´Briens. The Chief of the O´Brien clan, who has impeccable pedigree through the Barons of Inchiquin and of Thomond back to Brian Boru and hence to Cormac Cas is a member of our cluster which is good confirming evidence that Irish Type III is indeed Dalcassian. Many Irish Type III surnames have connections with the O´Briens, such as Bryant, Kennedy, MacNamara, O´Donnell, Butler, Casey, Hogan and McGrath. So Cormac Cas´ ancestors, may very well be the progenitors of this cluster.

I have had a paper published in the Journal of Genetic Genealogy. A set of Distinctive Marker Values Defines a Y-STR Signature for Gaelic Dalcassian Families which sets out my research. www.jogg.info/51/files/Wright.pdf

In the Links section there is a link to an out-of-print book Historical Memoirs of the O´Briens by John O'Donoghue, 1860. It can be read on-line or downloaded as a 21Mb pdf download. This gives valuable information on the connections to the O´Brien clan.

For a listing of Surnames found to have Irish Type III connections, Click Here. It must be stressed that having such a surname does NOT necessarily mean you are of this Irish Type III cluster.

SNP Testing and the Search for 'Our" SNP

Over 300 Irish Type III participants have some depth of SNP testing.

Walk Through the Y. Back in 2009, 10 members of the cluster donated $75 each to ensure one candidate from our cluster could participate in this important project. Thomas Krahn of FTDNA has searched 100Kb of the Y chromosome of a member from several L21+ clusters looking for SNP s that might separate these clusters. The chromats of our Irish Type III candidate revealed a SNP mutation which has now been called L226.

This marker, L226, has shown to be positive in the 300 that have so far tested, and importantly, negative in the hundreds of non-Irish Type III that have tested. See the Walk The Y page.

So with L226 being positive for our cluster we are called R-L226. L226 is the defining SNP for our cluster and so appears on the ISOGG 2017 R-Tree with the nomenclature listed as R1b1a1a2a1a2c1a4b2a. However as these "long" haplogroup names are constantly changing, it is better to refer to this clade as R-L226. Having a defining SNP means Irish Type III is no longer a 'cluster' ... it is a Haplogroup!

There is a project set up at Family Tree DNA for our R-L226 Haplogroup. All Irish Type III are urged to order the L226 SNP test, or preferably the R1b - L226 SNP pack test, and to join this project.

PLEASE - give your Kit number and say that you have tested L226, or the SNP pack, in your Request to Join.

Significantly M222 was found to be negative clearly differentiating this group from NW Irish that has been found to be positive on this marker.

Since November 2013, a new type of SNP test has been released from FTDNA called 'Big-Y'. This test is a NGS type where really vast lengths of the 'Y' Chromosome are analysed to find new SNPs. To read more on this fascinating development, see the Big-Y Testing page.

How old is this cluster

Using geneticist Anatole Klyosov's methods, a run using 336 haplotypes of 67 markers was conducted in September 2014 and gives a figure of 1450 ± 150 years to the MRCA. Our common ancestor lived between 350 AD and 650 AD. This is a little earlier than previously calculated but reflects a greater number of haplotypes in the calculation.

This gives an approximate time to TMRCA - so-called 'bottleneck' events, (where a previous colony of several/many people reach a situation where only one male has surviving male progeny and so all future members of the colony are descended from him), can mean that the progenitor of the haplogroup may have lived much earlier and so the haplogroup could be centuries older.

With the release of the 'Big-Y' NGS test we have found that there are a total of 20 reliable SNPs that are testing positive in ALL Irish Type III men. These represent the length of time from when our branch left the main 'R' phylogenetic tree to the 'bottleneck' event that resulted in our MRCA, around 350 - 650 AD. It has been found that SNPs occur about every 105 years, so our branch left the 'R' tree about 105 x 20 = 2,100 years before our MRCA. It seems this occurred around 1750 - 1450 BC.

What more can we do?

Firstly, please set up a Ysearch record if you have not already done so. This will allow you to compare your results (haplotype) with all the others in the largest database available to everyone, perhaps finding others with similar surnames that you have common heritage with. It will help others find you too. If you do set up a record, and have tested with a laboratory other than FTDNA, please be aware that there are several markers that may need conversion. See this Conversion Page. As you have then published your results publicly, I am able to include them in the results page of the 'Irish Type III' website. I will not post your results on the website unless you have a Ysearch record as I will always respect your right to privacy. We will, however, get the greatest gains by being prepared to share our information and hence get more and better matches to one another.

If you are looking to find relationships with others in this haplogroup, either with your surname or another, extending your testing to 67 markers could be worthwhile. Presently, 539 members have extended to 67 markers, and recently FTDNA have added additional markers taking the total to 111 markers, and some 138 have tested to this level. If you have already tested to 67 markers, it would be better to do some SNP testing rather than extend to 111 markers.

If you are a genetic distance (GD) of 8 or more from the NT4BZ modal, I would suggest testing the SNP L226 as final proof of membership of the cluster rather than testing either DYS463 or DYS716.

With the finding of the SNP in our haplogroup's WTY participant, L226, you are encouraged to test for this marker. See the Walk the Y page and SNP Markers. The SNP L226 is proof positive of haplogroup's membership.

But Perhaps a more suitbale test available now is the R1b - L226 SNP pack which tests for SNPs in each branch under L226 together with 100 'private' SNPs. Several new branches have been identified in this manner and this takes you down to hopefully your 'terminal'.

But the most extensive SNP testing now available, is the Big-Y test, see the Big-Y Testing page, which not only tests known branching but also discovers your 'private' SNPs and so is a 'discovery' test, rather than just a comparison test.

The Future

As time goes on, more will be discovered about the Irish Type III grouping, but be happy in the knowledge that the DNA of your ancestors is calling you from the Emerald Isle.

If your markers show that you are Irish Type III, and particularly if you have been SNP tested, I welcome contact with your results. I am particularly interested in those who now know their County of origin in Ireland, and/or are willing to have their results posted on this site. I would also like to show the known history of surnames, particularly those with connections to the Dál gCais O´Brien clan.