DNA Interpretations


The different links on the Society website provide a history of the Ó Donnchadha name and the various clanns/tribes which identify them.  The Y-DNA results are divided most clearly between the Kerry tribes of Eóganacht O’Donoghues, who claim descent from Eoghan Mór and the Milesian warriors of mythical times, and the several tribes of Donohoes of county Cavan, traditionally a branch of the Uí Briúin Bréifne.  In addition, there are a number of clusters that have possible connections to other Ó Donnchadha clans as well as clusters with current unknown origins.  Following a few general sections concerning recognizing haplotypes, we will discuss the clans/clusters we have identified.


In addition to the STRs that are tested to identify an individual’s haplotype, SNPs (Single-Nucleotide Polymorphisms) are also found on the Y chromosome.  Since SNPs play a significant role in differentiating some of the groups, a brief summary of them will be useful before proceeding to the particular clusters.

While both STRs and SNPs can back mutate (return to an ancestral value) SNPs are more stable than STRs and mutate less frequently so that they can clearly identify a subclade/branch.  They are used to separate the different haplogroups and their subclades.  The International Society of Genetic Genealogists maintains a haplotree at https://isogg.org/tree/, which shows the hierarchy from the root of ‘Adam’ and includes most of the subclades downstream of each designation, though it is by now rather out of date, unable to keep up with the ongoing discoveries as more gentlemen SNP test.

When a person has his SNPs tested, he is ‘ancestral’ for any particular SNP if he does not have a mutation at that position on the chromosome, and his ancestors’ Y-DNA never contained that mutation either.  He is ‘derived’, if his ancestor carried the SNP mutation that he also shares.  While much less frequent, it is possible that a chromosome will back mutate similarly to an STR, as described in the DNA Basics section on the Results page – https://www.odonoghue.co.uk/dna-project/dna-results/ – and the site of the SNP on the chromosome will revert to its ancestral state.

If a project participant has not yet tested for any SNPs, their haplogroup will be predicted by Family Tree and displayed as Predicted Y-DNA Haplogroup in the Badges box on the lower right of their Dashboard/Home page.  It is most commonly R-M269.  It also shows in red font on the ‘Results Chart (see links below).

If a participant has SNP tested, his result will be displayed in green font and indicate the terminal SNP particular to him.

A project participant can see where they belong on the haplotree from their own personal pages at Family Tree.  When they sign onto their account and click on the Haplotree & SNPs link in the Y-DNA Results & Tools section, the page will show them where their terminal SNP (either predicted or tested) is in the hierarchy.

Family Tree offers a variety of different SNP tests, from testing an individual SNP, to testing an SNP Pack, which tests a selection of known SNPs within a limited section of the haplotree, to testing the Big Y700, which is an extensive test covering a large part of the Y-chromosome and identifying any mutations found there.  This is where the discoveries are being made. The BIG Y test has become very popular with those interested in further defining their position within their subclade.  A huge number of new SNPs have been discovered through this test in all haplogroups and subclades.  The O’Donoghue of the Glens was the first in the project to avail of the BIG Y, and nearly 60 O’Donoghues have by now also received their results.

There are haplogroup projects to study the increasing amount of information about the various branches on the haplotree.  Elizabeth administers the R1b-CTS4466 Plus Project, which researches the Irish Type II subclade to which The O’Donoghue of the Glens belongs.  She is also a co-administrator of the R FGC11134 & Subclades project, which is the haplogroup upstream of R1b-CTS4466, and the R DF21 and Subclades project, which studies the haplogroup in which a number of the O’Donoghue Mór-Ross lineage belong.

Irish SNP’s

There are four main Irish subclades of the SNP L21, which is the most prevalent haplogroup in Ireland.

The first Irish subclade to be identified was the Northwest Irish Modal Haplotype/Type I, based on its distinctive marker values.  It was discovered within the genetic genealogy community by David Wilson in late 2004 and it was further studied during the Smurfit Institute of Genetics’ project at Trinity College and independently named the Irish Modal Haplotype.  They described the haplotype, predominating in the northwestern areas of Ireland, as being that of the Ui Neill. The TMRCA (Time to Most Recent Common Ancestor) they calculated of 1730 years ago has a standard deviation (SD) of 670 years that could place the common ancestor much later, or earlier, than the 4th century in which Niall of the Nine Hostages was most likely to have lived.  The current thought is that the haplogroup originated about 2000-2200 years ago.  Thus, while it is almost certainly an older subclade than the time of Niall, there was press and publicity about it when Trinity published their paper in the American Journal of Human Genetics in November 2005 which captured the public’s fascination, and the NWIMH/IMH has become synonymous with Niall, even to the extent that Family Tree uses it as a benchmark for those matching the modal.

In February 2006, research identified the SNP labelled M222 as distinguishing this subclade.  You can find more information about this Irish subclade at http://www.familytreedna.com/public/R1b1c7/default.aspx , where you can join the Family Tree R-M222 Haplogroup Project if you belong to this subclade.

The South Irish Type II Haplotype was identified by the respected physicist and citizen scientist Dr. Ken Nordtvedt in 2006.  It too had distinctive marker values, with the majority of males carrying it found in Munster.  Our O’Donoghue of the Glens matched this modal, and he was tested through the Walk-the-Y project in hopes that a defining SNP would be discovered to distinguish this tribe, but on the section of the Y chromosome tested, no unique SNP was discovered.  However, through the Geno 2.0 project at National Geographic, an SNP was discovered that defined the Irish Type II haplotype – CTS4466.  The BIG Y has since expanded the numbers exponentially, identifying a myriad of different branches within the main subclade of CST4466.  You can read more about them at the R1b-CTS4466 Plus Project – www.familytreedna.com/public/R1b-CTS4466Plus/default.aspx – that Elizabeth and several colleagues launched to study the SNPs defining the Irish Type II haplotype.  It is predominant amongst the surnames associated with the Eóganacht dynasty, but not limited to them.

In late 2009 a new SNP named L226 was discovered via the Walk-the-Y project at Family Tree which was determined to be a defining SNP for the Irish Type III haplotype, which predominates in the west of Ireland.  This is the haplotype of, amongst others, the O’Briens and the other Dál gCais tribes who are descended from the O’Briens in the genealogical tracts.  Though propaganda of the time claimed the Dál gCais descended from a brother of Eoghan Mór, in order to provide them with a royal lineage entitling them to rule Munster in opposition to the Eóganacht, the Dál gCais are considered by historians to have originated amongst the Déisi tribes.  Y-DNA has shown that L226 is not related to what is considered the Eóganacht genetic signature, hence confirming historical opinion.  There is a website created by Dennis Wright that is devoted to Irish Type III at http://www.irishtype3dna.org/ . It contains a thorough discussion of the findings to date.  The Family Tree R-L226 project is at https://www.familytreedna.com/groups/r-l226-project/about/background.

There is a Leinster Modal Haplotype identified by the SNP L159.2 with a dedicated project at Family Tree which can be found at http://www.familytreedna.com/public/R1b-L159.2/default.aspx . This mutation is somewhat volatile and the website explains that ‘This SNP is a parallel mutation that exists also within Haplogroup I2a.’ and also ‘The first discovery of L159 was within Haplogroup I-M26; it was then found within R-L21. FTDNA designated them L159.1 and L159.2, respectively.’ There are a number of observations made on the Goals page of the website.  For L159.2 found in Ireland, ‘The majority of Irish samples are from coastal Leinster (Dublin, Wexford, Waterford, Kildare) and Munster (Cork).  Group V on our third tab of Spreadsheet B matches this modal.

SNP testing in the Mór tribe have identified branches in the DF21 and Z253 haplogroups.  These will be discussed further below.

Palindromes and recLOH

Along the Y chromosome, there are sections which ‘loop’ out from the main strand for the DNA. Multicopy markers are often found on these loops, and the nature of such configuration sometimes creates a cross-over in a way that the allele value of one locus overwrites onto another, resulting in a loss of difference. This results in a ‘recombinational loss of heterozygocity’, or ‘recLOH’. For example, DYS 459a & b, whose modal is generally 9-10, becomes 9-9. DYS459 and DYS464 are both on palindromic loops and can tend to mutate at the same time.  Such corresponding mutation events appear to have occurred in the Irish Type III modal.

RecLOH events are considered to be more stable than STR’s but more mutable than SNP’s.

NPE – Non Paternal Event

This is a term used in the genetic genealogy community to indicate that the paper documentation regarding the parentage of the individual does not match what the Y-DNA reveals. This undoubtedly has the potential to create upset, but there is no need to jump to conclusions.

There are various reasons for an unexpected Y-DNA result. The person could be adopted into a family, or a father/grandfather/etc. could have been adopted. The mother may have remarried and the husband gave her children his name. In the case of the Irish, when surnames came into usage, it was usual that the people under the protection of the local chief assume his surname as part of the tribe. They were not always actually related to him. It also happened that people would take the name of a powerful individual, just to have the same name, regardless of whether there was any tribal connection or not.

In the case of the Raithlind O’Donoghues, they used the umbrella name of Clan tSealbhaig to encompass all the smaller tribes under their protection. This way, the people retained the name of their own head of family rather than assume the name O’Donoghue. That could be a reason for the more modest number of participants found to belong to the Mór tribe. In addition, a few years after the defeat at Kinsale, Rory O’Donoghue, the last acknowledged O’Donoghue Mór, took a company of men with him to the continent in 1606 and served in Spain, then later France. It’s likely that many of that company were O’Donoghue cousins, whose progeny have been lost to history. It would be interesting indeed if someday we find a match to the Mór lineage with a Spanish or French name. Testing in these countries is increasing, so there is such a possibility.

Groupings in the Results Charts

There are two charts available to see your results on the Family Tree website.  You should read through the introduction at the top of each page to understand how the data is presented.

Classic Chart – https://www.familytreedna.com/public/ODonoghue?iframe=yresults

Colorized Chart – https://www.familytreedna.com/public/ODonoghue?iframe=ycolorized

We have labelled each group to classify its common genetic signature.  Using the kits’ haplotypes and comparing the geographic distribution of their ancestors when known, we have done our best to identify a recognised tribe in which each member belongs.

The Eóganacht O’Donoghues of Kerry and Cork

Before discussing each of the Groups in the Results Charts, we would like to make some general comments about The Eóganacht O’Donoghues of Kerry and Cork, the most populous groups in the project.

According to Irish myth and legend, all the Eóganacht tribes descend from the second Eoghan Mór, who is purported to have died around 195 – 250 AD, depending on the source.  Almost all the traditional surnames of the different septs of Eóganacht in Munster are dominated by the Irish Type II haplotype and the SNP CTS4466, which could give some credence to the timeline and descendancy from Eoghan Mór, if it were not for the fact that the majority of tribes present in Munster prior to the emergence of the Eóganacht are also dominated by the Irish Type II/CTS4466 haplotype.  This is documented in Elizabeth’s Munster Irish research project – https://www.familytreedna.com/groups/munster-irish .  It is her opinion that though some clans may have a genetic relationship that supports the possibility of them having a common ancestor, the mythology uniting all the leading tribes of Munster into a homogeneous ancestry was politically motivated.  The Y-DNA evidence negates the likelihood that there is or was any true common ancestor of the Eóganacht tribes as the annals suggest.

Many histories describe the Mór and Glens lines as originating from two sons of Awly Mór (d.1158), described as the champion of West Munster, who staved off the attempted conquest of south Kerry by the O’Briens of Thomond, built the cathedral at Aghadoe and solidified the Eóganacht Raithlind presence in Kerry.  The Annals of Inisfallen record a number of sons of Awly Mór.  The two of most interest are Domnall and Conchobhar, from whom the two lines of Glens and Mór are said to have descended.  But where they really brothers?  This assumption seems to stem from one entry in the Annals of Innisfallen in 1178, where it is recorded ‘Conchobur Úa Donchada do marbad’, which translates to ‘Conchobar Úa Donchada was slain’.

In the edition of the Annals edited and translated by Seán Mac Airt, first published by the DUBLIN INSTITUTE FOR ADVANCED STUDIES in 1944, it is noted that the phrase {la Domhnall, lá [a] dearbrathair fein} was interlined by an additional hand, apparently at a different time.  Though the translation is shown as {i.e. by Domnall, his own brother} it may not be that simple.  While we don’t wish to impugn Mac Airt’s scholarly translation, dealing with old Irish can be quite difficult.  The Irish word used was ‘Dearbrathair’, which according to FOCLOIR GAEILGE-BEARLA by O Donaill, can mean both brother and/or kin.  So it could be foster-brother, or even brother-in-law.  It could even mean ‘dear friend’.  To our knowledge, there are no other contemporary records that suggest this relationship, and this single entry poses several questions.  Who knows when it might have been appended, by whom, or why?  It would seem that all later references of the two sons hinges on this possibly misunderstood term.

Our current Chief of the Name, Geoffrey O’Donoghue of the Glens, belongs to one of the branches of the Irish Type II haplotype, commonly found in the different Eóganacht septs.  Tighe O’Donoghue/Ross (the official historian of the Society) has a very detailed family tradition that his ancestors belong to the line of the O’Donoghue Mór.  Some of this history has been recounted in Tighe’s article ‘The O’Donoghues of Ross’ in the January 2002 Journal.  Tighe’s Y-DNA results differ from that of The Glens, which suggests that the two Kerry Eóganacht O’Donoghues did not, in fact, descend from brothers.

The Y-DNA project has overturned that assumption, by clearly separating the lineage of The O’Donoghue of the Glens from that of the Mór. This is not a particular surprise, since several historians (Canon O’Mahoney, Butler) noted that there were two separate Uí Donnchadha tribes in the first millennium, that of the Eóganacht Cashel and the Eóganacht Raithlind.  A careful search of the annals confirms contemporary O’Donoghues of different lineages in the 11th century.

The research initiated by our first administrator, Prof. Tom Donahue at the outset of the project has indicated that the Glens tribe is of the Hy Donnomoii, the senior branch of the Eóganacht Cashel, which also includes the McCarthys and O’Sullivans.  According to the annals, their likely progenitors were thought to have separated from the Eóganacht Raithlind around the 5th century when Corc of Cashel was supposed to have established his tribe in Tipperary after his group’s return from several generations in Wales, raiding the Roman settlements there.  However, SNP testing has identified that The Glens belong to one branch of the CTS4466 haplogroup, while the main line of O’Sullivans are in a completely different branch of CTS4466 and are not likely to be related to the Hy Donnomoii within the suggested timeframe of the annals.  In addition, while there are several different branches of McCarthys who are CTS4466, extensive research by Nigel McCarthy through the McCarthy Surname Study has shown that the main line of the McCarthy Mór lineage is actually in a different haplogroup altogether.  Likewise, the Raithlind/Mór lineage is also in a different haplogroup than The Glens, which will be discussed shortly.

A – A3. The O’Donoghue of the Glens tribe

The Glens’ ancestor, Dúngal Ua Donnchadha, Petty King of Cashel (+1025) ruled in Tipperary until the mid-century when these Ui Donnchadha finally lost control of the province to the O’Briens.  By the 1100s they were driven from power and out of Tipperary by the McCarthys, and we see little of them in the annals for the next century.  Later histories contain uneven references to these Cashel O’Donoghues and they are sometimes not mentioned at all, but that could be said of other families as well, depending upon the sources used.

It is likely that they were scattered after they were forced from Cashel.  In that time, the various families would have made their way the best they could, though the majority of them probably remained in the Cork/Munster area.  By the time surnames came into practice, they could have taken a local surname, but the royal lineage is finally seen again in Kerry, first in Glanerought.  The Glens line eventually settled in part of the Mór territory east of Killarney along the glen of the river Flesk.  There must be an explanation why they would be allowed do so in the territory of Awly Mór.

The contention that The Glens’ ancestor was a son of Awly Mór is possibly due to the scion heir of Cashel being adopted or fostered by the O’Donoghue Mór Chief.  There was a common practice noted in the Brehon laws that P. W. Joyce explains in his Social History of Ancient Ireland. “An adopted person was called Mac Faosma, literally ‘son of protection.’ Sometimes not only individuals, but smaller tribes, who for any reason had migrated from their original home, were adopted; who were then known as finé-taccuir, i.e. ‘a family taken under protection’.” This could explain the common notion that the Mór and Glens lines were from sons of Awly Mór. There is no other adequate explanation for why Awly Mór’s territories were divided after his death, rather than his táiniste/son being given rule of the whole territory, which would have been the normal method of succession.  The two lineages retained close ties of kinship throughout subsequent history.

The current O’Donoghue of the Glens Y-DNA tested at the outset of the project, and his haplotype matched the Irish Type II modal.  At that time, SNP testing was in its infancy, and it was automatically assumed that anyone who also matched that modal was related to The Glens.  As it happens, almost everyone who matched the Irish Type II modal had family origins around Glenflesk.  However, with the advent of increased SNP testing, a number of different branches beneath CTS4466 have been identified, making clear that not all Irish Type II O’Donoghues are directly related through the male line to the Chief.

This would not necessarily mean that the other Irish Type II O’Donoghues with ancestors from Glenflesk were not part of the tribe.  As explained in the section above, NPE – Non Paternal Event, it is impractical to expect that all members of a tribe were literally related to the chief, and there would surely have been intermarriage through the female line of the families living in the territory.  This makes them no less members of the tribe.

We have clustered the Irish Type II individuals into several categories.

A. Eoghanacht Cashel/The Glens – CTS4466 – A802 > A914 > BY121634+ – The Chief of the Name & the descendant of the 17th century Duff line.

Our first group in the Results is that of The Glens himself and a distant cousin with a pedigree going back to the 17th century when his Duff line descended from a brother of the chief of the time.

A1. Eoghanacht Cashel/The Glens – tested or likely A802 / BY3531 – The Chiefly line.

This second group is by their haplotype match and/or SNP testing, likely descended closely from the family of The Glens at some point in the past, since that Glens genetic signature has an unusual mutation from 15 to a 13 at DYS485.

A2. Eoghanacht Cashel/The Glens – CTS4466 – other branches

This group contains the other Irish Type II haplotype O’Donoghues who are in a different branch of the Irish Type II tree, nevertheless united by their origins in Kerry or Cork.

A3.  Uí Dhonnchadha of Ossory

As pointed out in the Historical Origins section of the Society website, ‘the O’Donoghues of Ossory were a branch of those of Cashel, whose territory was given to the kings of Cashel by the people of Leinster as recompense for the death of their king, after he was slain unlawfully at the Hill of Allen in Kildare by a king of Leinster.’  The territory of the Uí Dhonnchadha is recorded as being Magh Mail, which is in Kilkenny.

Early on in the project, two Dunphy’s from Laois, just north of Kilkenny, tested to 67 markers to confirm if they were related.  The results showed that they are, though distantly.  More recently, a third Dunphy joined the project, who also has a distant relationship to the first two Dunphys .  His family came from Kilkenny.  This would seem fitting, since it is said that the name Dunphy arose in the Osraighe territory.  Previously, none of the other Dunphys in the project appeared to support that contention.

There are several participants whose birth name is O’Donoghue.  For one, his results exactly match another Glens member, and they have communicated to discover a common ancestor, which has opened up a whole new family history to enjoy.  This is a wonderful success story.

We have a McDonough and a McCarty who match O’Donoghues far closer than others of their surname.  It’s quite likely that their heritage is the McDonogh McCarthys from centuries back who Rod has always suspected were O’Donoghues.  He discusses this in his Jan 2003 article O’Donoghue tribal history in Cork and Kerry

B – B3. The O’Donoghue Mór tribe

The O’Donoghue Mór tribe belongs to the Eóganacht Raithlind, which also includes the O’Mahoneys.  This tribe of Eóganacht is considered by many to be the senior branch, with the other tribes separating from them and establishing their own identities at various times through the centuries.

Within the Mór tribe, there are several subgroups of individuals.  The Results Spreadsheet separates those smaller subgroups.  Initially, it was presumed that they were all related at some point in the historical past of the Eóganacht Raithlind.  However, with all the additional SNPs that have been discovered and tested, it has become apparent that while these separate groups have a historical connection to the tribe, they do not all share a genetic relatedness as had been anticipated.

B. Eoghanacht Raithlind/Mór-Ross – DF25 > DF5 > BY11464 – The Chiefly line

Tighe O’Donoghue/Ross (the official historian of the Society) is the basis for Group B, along with his ‘cousins’.  His family tradition of descending from the Mór/Ross lineage was instrumental in recognizing that there is indeed a separate lineage of that lost dynasty from the 1583 death of Rory O’Donoghue Mór and the later attainder in 1586 of the last documented O’Donoghue Mór of Loch Lein, his son, also named Rory.  According to family tradition, the Mór family moved to the Glens lands after the attainder and remained there till the Rightboy movement of the Tithe wars, when the then O’Donoghue of Ross became Captain Right, the leader of the movement (see ‘Captain Right – The Rightboy Movement and the Tithe Wars’ in the Jan 2004 Journal).  Eventually caught and banished to the Burren of Clare, Tighe’s grandfather was a descendant of those rapparees who emigrated to the US from that county in 1905.  Since his testing, six more individuals have joined the project and have been found to match Tighe. Big Y testing has confirmed the relationship, three of them share the same terminal SNP, a fourth a known relative.  Two of them, and another not SNP tested, are aware of their Clare roots, though their family’s’ illustrious/infamous history was lost in the mists of time and the tribulations of staying alive on that barren landscape until the present day.

Kit B9394 was the first to test the Big Y-500, and both Tighe/12092 and kit 600366 ordered the R1b-FGC5780 SNP Pack, which included a number of B9394’s ‘private’ SNPs.  They both matched all kit B9394’s SNPs (except one that didn’t provide a result [a dud…]) confirming their close familial relationship.  Eventually, B9394 upgraded to the Big Y-700 and Tighe and two other matches tested the Big Y-700 – all share BY11464.

We unfortunately have not discovered any O’Donoghues around Killarney that are remnants of that family before they were banished to the Burren.  There is one gentleman with only 12 markers tested, with whom we have lost touch, so we are unable to discover more about him and him family origins, though the given name suggests he may be one of this group.

B1. Eoghanacht Raithlind/Mór-Ross – DF25 > S6185 > BY39558

This group are distant cousins to the chiefly line, insofar as they split in their genetic history with them at DF25 and travelled down a different branch of the tree.  This group includes our founding Group Administrator, Prof. Tom Donahue, whose family tree leads him directly to Coomacullen Mountain about three miles from Glenflesk.  While he originally supposed that his geographic location placed him within the O’Donoghue of the Glens tribe, his haplotype indicated otherwise.

Kits 358147 and 643196 have tested the Big Y, and a surname-specific branch for them was identified – BY39558.  It is likely that all the gentlemen in this group are positive for BY39558.

Kit 190709 is a genetic distance of one at 37 markers from 25488, and they have been able to find a common ancestor back in the 18th century.  More recently, an adopted gentleman, N61117, has also discovered that he is related to both 25488 and 190709, giving us more success stories in finding cousins.

Kit N61117 also tested the Big Y and was initially given the terminal SNP of BY39558, suggesting all those in this group would prove positive for BY35998.  However, his terminal SNP has recently been changed to BY211604, interestingly matching kit 296146 in the B3. Group – more on this below.

B2. Eoghanacht Raithlind/Mór-Ross C – Z253

There are fifteen gentlemen in this group, including our Society founder Rod O’Donoghue and our new Co-Administrator Mike Donahue, many of whose known ancestors hail from Kerry to Limerick, which would have been the northernmost reaches of the original Mór territories.  Nine of them share an unusual marker value of 12 at DYS392, the rest have the usual modal of 13.

The first nine all have relatively close connections, several with a known common ancestor in a family of four brothers in the early 1800’s.  Most of the other participants in this group, including Rod, have in all likelihood a connection near the time of the four brothers – perhaps a generation or two further back.  They are still searching records to see if they can find their common ancestor.  Rod has found his own origins in Ireland (See Serendipity or what! in the January 2012 Journal,  The O’Donoghues of Ballyduff, North Kerry and its environs in the April 2012 Journal and How did the O’Donoghue name get to North Kerry? in the July 2014 Journal).

Rod and three matching kits have tested the Big Y-700 and are in the PH3937 branch of Z253 beneath A503.  Kit B99579, which is one of the five with the 13 at DYS392, has tested the Big Y-500, and his terminal SNP is BY128058 in a ‘brother’ branch of A503.

Now, the age of A503, the two clusters’ common ancestor, is estimated to be roughly 2500 years ago, which is quite a long time to consider them any kind of ‘cousin’. None of the second five have known origins, so it’s possible their tribal affiliation is a bit wider than the Raithlind O’Donoghues.  However, until/unless new information gives us better insight, they remain in the B2 group.

B3. Other surnames matching the Raithlind/Mór-Ross – DF25 > S6185 > BY39558

These two individuals do not share the O’Donoghue surname, but their Y-DNA clearly identifies them as having common ancestors with them.  Kit 296146/Creech has Big Y tested, and he shares the same terminal SNP as kit N61117/Thornton (adopted surname) in the B1 group mentioned above.  Kit 296410/Smith-Gomez has not SNP tested, but at the 37 marker level (as far as he has tested) he matches kit 296146/Creech, another Creech, and N61117/Thornton and his two known Donehoo/Donahoo relatives.  Quite a mix of names…  Smith-Gomez shows no ancestral surnames, but Creech goes back with that surname to 1795, so it must have been a long time ago that these two gents had name changes in their family history.

While both the Glens and Mór/Ross groups contain individuals that are not directly related to the chiefly lines, this does not mean that these clusters were not related at all.  Those in the tribes could not conceivably all have been related family members through the male lines.  There could have been a number of independent groups of cousins loyal to their leader.  By the nature of things, there would have been continual intermarriage between these tribal members as a matter of course.  Families tended to stay within the tribal territories into which they were born.  They received protection from the chief of the territory, something which they would lose if they moved or travelled into a different territory.  That was the way of it in those tribal days.  The similarities in physical characteristics in Kerry/Cork O’Donoghues, the similarities in geographic origins of their families and ancestors, some within 25 miles or so from each other, all tell us they are related at some level.

Cavan Donohues

There are five different subgroups of Donohue/Donohoes in the Project. They cross over with groups in the Breifne Clans project.  Joe Donohoe had begun that project and led the research of those various tribes.  We have his major 11-part report of 2009, completed shortly before his passing, available amongst the Y-DNA Reports. Since then, other administrators have rearranged the Results spreadsheet and little has been done to advance Joe’s work.

C. Cavan Group A – M222

The Cavan Group A modal matches that of the NWIMH, the Northwest Irish Modal Haplotype.  While the NWIMH definitely has a geographic distribution across the northern counties and over the channel into the Scottish highlands, it’s unlikely its origins can be attributed to any specific tribe.  Joe discusses this subclade in his BCP Report 5 Part 1 and Part 2.  Since that report, two of our participants have tested the Big Y and found to be in two different branches of M222.

C. Cavan Group B – L513

The Cavan Group B belongs to the L513 haplogroup.  Kit 262020 has tested the Big Y and his terminal SNP is BY2940.  It is likely that all those in Group B would test positive for this SNP.  This group is discussed in Joe’s BCP Report5 Part 4.

C. Cavan Group C – L513

The Cavan Group C is also likely to belong to a different branch of L513, though no one in the group has yet SNP tested to confirm.  They have more matches in what Joe described as the ‘FD2MaguireGroup’. According to his research, the Donohoes of this group (originally MacDonaghy) are a 15th century branch of the McGuires, descending from a Donnchadh Maguire.  Group C is discussed in his BCP Report 5 Part 8.

C. Cavan Group D – U152

The Cavan Group D are in the L20 branch of the U152 haplogroup.  Kit 96227 from the Clan Donnachaidh project joined ours since his haplotype matches these men rather closely, and his TMRCA is also closest to theirs. He is tested L20, and a second kit is also tested L20, which supports the probability of the whole cluster being L20. This group is discussed in Joe’s BCP Report 5 Part 6.

C. Cavan Group E

There is also a Cavan Group E, since two individuals of other surnames have joined the project who match more closely to Donohues than their own surname.  Two Donohues in the group had been in a subset of Group B, but the new members made it more appropriate to give them a separate grouping.  Another Donahue has since joined them.  Though there has been no SNP testing, it’s possible they are also a branch of L513.

D. Uí Dhonnchadha of the Déisi Mhumhan – L226

This cluster is defined by the SNP L226 mentioned earlier as Irish Type III.  The Deisi are considered an Erainn tribe whose territory was in the Midlands.   A contingent was historically sent to Clare to conquer the local tribes there, and it was from them that the O’Briens descend.  As the tribe rose to prominence at the time of Brian Boru, whose descendants are known to be L226, they claimed to be descended from a brother to Eoghan Mór, Cas.  This claim has been dismissed by later historians, and the DNA evidence supports that dismissal.

Since this L226 cluster matches the Déisi of the O’Briens, it’s reasonable to believe that this group is of the Uí Dhonnchadha of the Déisi Mhumhan.  The territory of the Uí Dhonnchadha of the Déisi Mhumhan was in Waterford/Tipperary.

There are seven O’Donoghues, most whose families originate in either Offaly or Tipperary.

We also have two Dunphys matching this modal.  Kit 154629 has origins atypical of the others, in Cork back to the early 1800’s. (There is an article about his family in the April 2009 Journal.)

E. Airghialla 1 – null DYS425

There are two occasions when an Eóganacht tribe was overlord of the Erainn Osraighe tribes of the lands in Ossory, which the Historical Origins link describes as comprising County Kilkenny and certain parts of counties Tipperary and Laois.

The Eóganacht held sovereignty over the Osraighe territories in the 6th century, prior to the local tribes wresting back power and ruling the territories themselves. However, due to an unlawful killing of the Cashel King by the King of Leinster in the mid 700’s in a battle at the Hill of Allen, an eric (fine) was imposed, and part of the Osraighe territory from Gowran in Kilkenny to Dungrianan in Tipperary was given to the neighbouring Eóganacht Cashel. O’Hart indicates it remained under their control until the end of the 12th century when Normans seized it.

In addition to the Eóganacht sovereignty, there is also record of an O’Donnchadha tribe being kings of Osraighe along with the O’Carroll’s and MacGillipatrick’s. While there is record of Donal Mac Firbis saying that these O’Donoghues were of Eóganacht origins, it is also possible that they were Erainn. In the April 2009 Journal, Eóin Ó Donnchadha wrote a brief article as an introduction to the Ua Donnchadha sept of Osraighe. His own origins go back to north Wexford, which is not far from the traditional Osraighe territory. He and a Dunphy (Dunphy origins are said to be in Osraighe, though more on that below) share an unusual allele, and Eóin’s own research uncovered that a number of Carroll’s matched his and Kurtis Dunphy’s uncommon null 425. Initially, that supported a connection between the Ósraighe Ua Donnchadha and the O’Carrolls of Ely, whose territory is in Osraighe.

However, as mentioned in the October quarterly report, Joe Donohoe’s 2009 annual report for the Breifne Clans project contains a well-researched, thorough discussion of Oriel surnames and the Airghialla clans of the Oriel territories, including parts of counties Armagh, Monaghan and Louth, abutting Cavan. There are a number of these Oriel families who contain members with null 425’s (which Eóin and Kurtis share), and there are a tribe of Oriel Carroll’s in this territory. Hence the Carroll’s who are null 425 are probably Oriel O’Carroll’s.

There is a Family Tree project devoted to the Ely Carroll’s and I’ve been in touch with the administrator. The pedigree of one of the clusters of Carroll’s considered Ely supports that the cluster is indeed Ely, and their ancestral haplotype does not match that of our two participants. This makes it unlikely that there is an Osraighe connection for our two null 425 participants.

Eóin has also researched the Teallach Modharain Ó Donnchadha, of which, as indicated in Rod’s book, little is known. Their territory appears to abut Airghialla tribes, but so far there has not been found any sources which include them in the Airghialla. Joe points out in his BCP Report 5, Part 7 that there are no obvious associations between the Dunphy/Ó Donnchadha names and the Airghialla, but the three men in this group match Joe’s ‘Airghialla 1’ signature, hence the title of the group.

F. Mac Donnchadha – M222

Up to now, anyone with the Irish Type I/Northwest Irish haplotype has been placed under the Cavan/Briefne tribe.  This was convenient, but perhaps not the most correct way to look at it.

One Donahue gentleman whose family came from county Tyrone matches most closely to Donaghys.  From conversing with Donaghy researchers and searching blogs, he was able to discover that Donaghys from Tyrone emigrating to America changed their spelling to Donahue and conversely that Donahues in America had relatives in Ireland using Donaghy.  Now, MacLysaght shows Donaghy as a variant of MacDonagh in Tyrone; and there are several septs of Mac Donnchadha known throughout Ireland.  One sept in Cork is considered a branch of McCarthys that Rod discusses and suggests ‘were O’Donoghues who decided to align themselves opportunistically with the MacCarthys’ on The Society website – https://www.odonoghue.co.uk/family-history-research/names-variants/

In any case, in 2020 we have added a new group/sept of Donahue/Donaghey/Donehue – ‘F. MacDonnchadha – M222’.  We are thankful to the help of our member in identifying this sept and encourage others who have been researching their own line of O’Donoghue/Donohue to likewise share their discoveries in hopes of further expanding our understanding of the origins of the name.

G. Uí Chormaic of County Galway? – Z253 > S7898

These two kits are not terribly close matches but share several relatively unique marker values, suggesting they have a common ancestry.  One has already tested the Big Y and they both would likely share a surname-specific terminal SNP below Z253 >> S7898 if the second man tested the Big Y as well.  The family of the untested gent hales from Inis Mor, Aran Islands, Galway, and they might be members of the Uí Chormaic of County Galway, whose historical territory was in that neighbourhood, hence they have been classified in group G.

H. Eoghanacht Ninussa? – FGC5494 > FGC61830

This tribe was found in the territories of North Clare and the Aran Isles.  There is a territorial overlap with the Aran Islands of the previous group G – the islands lay off the coast of south Galway and the north coast of Clare.  The two gentlemen in this group are close matches, the first with known origins in north Clare, hence our determination of a likelihood of being the Eoghanacht Ninussa.  The second kit was Big Y tested to FGC61830 and is indicative of the haplogroup for both.

I. Uí Dhúnchadha of counties Wicklow and Dublin? – L159.2

The three members in Group V match the Leinster modal haplotype.  One has known ancestry in Athy, Kildare, another in Rathinmy, Wexford, both in the broad Leinster area consistent with the modal.  It’s possible they are remnants of the Uí Dhúnchadha of counties Wicklow and Dublin.

J. Clusters

We have labelled the smaller unidentified clusters (insofar as we are not currently aware of a known tribe of O’Donoghues to which they are likely to belong) as Group I through VII.

J. Clusters – Group I – L513

This cluster has gents from Clare/Cork to Kerry to Unknown, but they do match each other close enough to be considered a true cluster.  Kit 11003 has tested positive for the SNP L513, and the rest in that cluster would probably be positive also if they tested.

J. Clusters – Group II – Z253

Kit 366249 has tested Z253 and several other kits are close matches.  Overall, all the kits would probably be a branch of Z253 if tested.

J. Clusters – Group III – U106 > BY102780

Kit B204842 has Big Y tested to BY102780 under U106.  This is not a common subclade for Ireland, but he has Donoho matches, and the surname certainly places his origins as Ireland.

J. Clusters – Group IV – Z16943

These kits all have the same common ancestor, going back to 1776.  They don’t know where in Ireland their family originated, but as in Group III, it must certainly be there somewhere.

J. Clusters – Group V – I-P37

These two participants, though not SNP tested, are predicted to be haplogroup I-P37.  One is a gentleman recruited to the project who currently lives at the edge of Glenflesk.  He matches, perhaps within a genealogical timeframe, an individual who has roots in Cork, with a paper trail to the late 1800’s. Prior to their testing, they would both have been candidates for the Glens tribe.  There could be a number of explanations for why they are not. While not genetically an O’Donoghue on the male line, it is possible that there was intermarriage with female O’Donoghue lines in the distant past prior to the taking of surnames, and being in the tribe, would have adopted Ó Donnchu when surnames were taken. As it happens, the Kerry member has an exact match with a Healey in the Family Tree database.  Haley is a west Cork name.  And coincidentally, there is a different Haley in our project who matches our Glens tribe, also from Cork.  It could be inferred from this that a related group of haplogroup I-P37 individuals were living in west Cork and affiliated with the Glens Eóganacht.  When surnames were taken, they split in some way, resulting in some taking the name Haley and others assuming the tribal name of Ó Donnchu. Their loyalty and heritage would be with the O’Donoghue tribe, even if their genetic heritage was different.

J. Clusters – Group VI – I-P37

These three gents are also predicted to be I-P37, though their haplotypes indicate a completely different branch of P37 than the previous cluster.  They do match each other, but none know where in Ireland their families originated.

J. Unaffiliated R1b

We have a number of members who are members of various different R1b haplogroups. While they have the name O’Donoghue, of various spellings, we have not yet found any surname matches, and their genetic heritage is different from the members in identified tribes. There could be various reasons for these differences, such as suggested above in the section ‘NPE…’ or we are just waiting for a match to test.  We await more participants in hopes that matches will be discovered.

K. Haplogroup R1a1

We also have three participants in haplogroup R1a, though none of them match each other closely enough to be considered ‘related’.

These latter groups all patiently await new testers to discover their closest ‘cousins’.

L. Haplogroup I

There are six participants who are predicted or tested to several branches of haplogroup I.  None are close matches to each other.


By now we have nine Dunphys in the project.  Interestingly, they are in six different groups, each with diverse haplotypes, making clear that there was no single origin of the Dunphy name, even though it has traditionally been considered a chosen spelling change by O’Donoghues in the Osraighe area (see the ‘A3.  Uí Dhonnchadha of Ossory’ section).


We have three Dannehy/Danaher/Danehys in the project whose closest matches are Donahue/ Donoghue/O’Donoghues.  While we have not any found record that connects the name to O’Donoghue, it is a Cork/Kerry surname and a number of them have a South Irish haplotype, including the three in our project.  There is no project devoted to Dennehy, and while the Denning project does have seven participants of that name variation, the others are not South Irish.  All our Dennehy participants originate from Kerry.  In the October Journal, Rod wrote about the apparent relationships in Danaher-Dennehy-O’Donoghue: How they overlap.

As new information is added to the link, it will be noted in blue to identify it as new material. If there is any aspect of the information which you would like to see expanded or addressed, please let Elizabeth know.

Last updated September 2021

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