Monday 27 March 2017

The Cork Gleeson's - birth of a new genetic family

At the Gleeson Clan Gathering in August last year, I presented an evaluation of the DNA evidence thus far and asked the question: does the DNA evidence support what we know of the origins of the Gleeson surname from historical texts and documentary evidence?

You can watch a video of the presentation here (the relevant section starts at 21:25). The review of historical texts included an evaluation of some of the following strands of evidence. This analysis needs to be completed and I will attempt to summarise the findings in subsequent blog posts but for now I include links (where available) to the main sources in case anybody wants to explore these themselves:
  • Surname Dictionaries written by MacLysaght, Woulfe and O'Hart (you can read about these in a previous blog post here)
  • accounts of the Gleeson name in Ancient Texts such as ... 
  • secondary sources such as books by the following authors:
    • Dermot F. Gleeson - The Last Lords of Ormond (1938) and A History of the Diocese of Killaloe (1962) ... watch a video of a lecture about him by local historian Danny Grace here from the Gleeson Clan Gathering, August 2016)
    • Rev. John Gleeson - History of the Ely O'Carroll Territory (1915)
    • David Austin Larkin (Irish Septs, 2007)
  • articles from academic journals, including ...
    • JCHAS, Journal of the Cork Historical & Archaeological Society (1895-1945)
    • THJ, Tipperary Historical Journal (1988+)
    • NMAJ, North Munster Antiquarian Journal (1936+)
  • Surname Distribution maps
  • other miscellaneous sources (e.g. Clans of Ireland website, etc)

One of the main conclusions from this overview was that there are potentially three separate origins to the Gleeson surname and its variants - one in North Tipperary (represented in all probability by Lineage II within the DNA project), one in Ulster (McGlashin), and one in East Cork, centred around the area known as Imokilly from the Gaelic Uí Macc Caille or Uí Meic Caille (a group I have dubbed "the Imokilly Gleeson's"). The Imokilly Gleeson's have been present in Cork since the 1100s when they were land stewards ("betaghs") for the FitzGerald family (1). However, one of the enduring questions that has continued to intrigue me is: did the Imokilly Gleeson's and the North Tipperary Gleeson's arise from the same stock ... and therefore, will they bear the same genetic signature?

Well, it would appear from the recent results of a new project member that the answer to that question is: No - the North Tipperary and Imokilly Gleeson's are separate and arose from different origins ... at least for now (until further DNA evidence emerges to the contrary).

The Uí Glaisín were a sub-sept of the Uí Meic Caille who were a sub-sept of the Uí Líatháin

Up till now, there has been no one with the surname Gleeson from East Cork in the project. But that changed recently thanks to the efforts of Phyl Irwin from Cork and David Gleeson from Thurles who are helping to recruit new members to the project from the Cork area. David paid a visit to Youghal (in the heart of Imokilly) and recruited a new member (DG-8367*) who has a Gleeson pedigree that goes back to 1833 in Pilmore, Youghal, Co. Cork. This new members Y-DNA-37 results came back from the lab last week and they are very revealing indeed!

STR marker analysis

DG-8367 (G-109) has 98 matches at the 37 marker level and 286 at the 25 marker level. But his closest match is another project member who until now has been residing in the Ungrouped section. DG-8367 matches PMG-6085 (G-101) with a Genetic Distance of 1/37 (i.e. one step away from an exact match). Together these two close matches have formed a new genetic family, Lineage V (the Cork Gleeson's). 

Neither of these two individuals have any other close matches within the project.

The single mutation between these two individuals is on the marker CDYb, which is a very fast mutating marker, and this supports a very close relationship between the two project members. The second project member (PMG-6085) has a contradictory family history - some family members maintaining a Belfast origin for their Gleeson ancestors and some maintaining a Cork origin. The DNA results would lean strongly toward the latter.

The TiP Report for these two people suggests that there is a 95% chance of them being related in the last 7 generations and 74% chance within the last 3 generations. Taking the former estimate, this would mean that the two families of Lineage V have carried the Gleeson surname since the mid-1700s (i.e. 7 x30 = 210 from 1950 = 1740). However, it is not clear if the surname was associated with the same genetic signature prior to this time. We would need more Cork Gleeson's (with a more distant relationship to these two members) to join the project in order to get a better estimate of how far back in time the Gleeson name and the particular DNA signature of Lineage V are associated. It may only go back as far as the 1700s, or it might go all the way back to the origin of the surname about 1000 AD. At this stage, we simply cannot say one way or the other.

Comparing the pedigrees of both men does not reveal a common ancestor. The MDKA (Most Distant Known Ancestor) for DG-8367 is a Michael Gleeson born about 1833 in Pilmore, Youghal, Co. Cork; and for PMG-6085, the MDKA is Patrick Gleeson born about 1852 in "Ireland" (possibly Cork). These two MDKAs may have been brothers or first cousins, making our two project members 3rd or 4th cousins. This could be explored further if the two members both undertook autosomal DNA testing and/or upgraded to 67 or 111 STR markers.

Surnames of Matches

Looking through the list of surnames in each of these two mens matches, what stands out is a number of repeating surnames, some of them rather unusual (e.g. Anglin, Mauck, Popkins, Rippere). Where available, the place of origin of the MDKA throws up interesting conundrums - Islay, Orkney, Co. Down, Co. Donegal ... but no obvious origins in Cork.

Matches of DG-8367 (at 37 marker level)
Anglin/Anglen ... x14
Conner ... x3 (1 from Carlow)
Enderton ... x2
Enright ... x3
Guthrie ... x3 (same ancestor)
Mauck ... x2
McEachern ... x2 (1 from Islay, Scotland)
O'Donoghue ... x2
Popkins ... x2 (1 from Orkney)
Rippere ... x2
Roddy/Ruddy ... x9 (mainly from Co. Down; most have same ancestor)
Sinclair ... x2 (1 from Islay, Scotland)
Spain ... x7
Wright ... x2

Matches of PMG-6085 (at 67 marker level)
Anglin ... x4
Conner ... x3 (as above)
Dever ... x2 (both from Kilmacrennan, Donegal)
Devine ... x6 (all from Conwal, Co. Donegal; most have same ancestor)
Enderton ... x2
Guthrie ... x3 (as above)
Leonard ... x2
Mauck ... x2
McCauley ... x3 (1 from Islay, Scotland)
Moore ... x3 (same ancestor)
Roddy/Ruddy ... x9 (as above)
Wright ... x2

In addition to the above, there are two Norman names that stand out, although these are only single occurrences - FitzPatrick and de Burca. Nevertheless, the area around Imokilly was for many centuries a Norman stronghold and both the Barry family and the FitzGerald family held sway here.

However, even though these surnames do not appear to be quintessentially Gaelic, there is not a huge amount that can be concluded currently from this interesting array of names. However, a more complete surname analysis (using surname distribution maps) will be included in a subsequent blog post.

SNP marker analysis

Here is the list of "downstream" terminal SNPs associated with the matches of these two members:

Matches of DG-8367 (at 37 marker level)
BY11270 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411
BY390 ... x2 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > FGC32363
CTS10651 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > FGC32363
CTS3087 ... x2 ... sub L513 > S6365 > BY16
FGC13422 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > FGC32363
FGC32363 ... x1 ... sub L513 > S6365 > BY16 > CTS3087
L513 ... x6
Z17626 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > BY11289

Matches of PMG-6085 (at 67 marker level)
BY11270 ... x1 ... (as above)
BY11284 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > BY11289
BY11286 ... x1 ... sub L513 > S6365 > BY16 > CTS3087 > FGC13411 > BY11289
BY390 ... x2 ... (as above)
CTS10651 ... x1 ... (as above)
CTS3087 ... x2 ... (as above)
FGC13422 ... x1 ... (as above)
FGC32363 ... x1 ... (as above)
L513 ... x4
Z17626 ... x1 ... (as above)

This analysis strongly suggests that these project members sit on the L513 branch of the Y-Haplotree (Human Evolutionary Tree) and furthermore, sit on one of the branches downstream of the SNP marker FGC13411. The overall SNP Progression for Lineage V is therefore likely to be as follows:
R-P312/S116 > Z290 > L21/S145 > DF13 > L513/S215/DF1 > S6365 > BY16 > CTS3087 > FGC13411 > ... and either FGC32363 or BY11289

The Cork Gleeson's are likely to sit somewhere below FGC13411

This could be confirmed by further SNP marker testing. The L513 SNP Pack has recently been overhauled and split into 3 downstream SNP packs. The new S6365 SNP Pack includes all the SNP markers relevant to Lineage V and for those interested in further downstream SNP testing, this new SNP Pack or the Big Y test are the preferred options.

YFULL provides the following approximate dates for the emergence of the various SNP markers (and hence the branching points they represent):
  • L513 ... 4300 years ago
  • S6365 ... 3900 years ago
  • CTS3087 ... 3600 years ago
  • FGC32363 ... 1650 years ago
  • Z17626 ... 1650 years ago
So further SNP marker testing will move these project members further downstream along the Haplotree to about 1650 years ago, which is about 350 AD, a time when the Gaelic clans were just beginning to emerge.

Looking at the L513 section of the Haplotree on Alex Williamson's Big Tree, and in particular the FGC13411 sub-branch reveals that it contains a mixture of Scottish and Irish names. There are too few people tested at this point to draw any firm conclusions about the origins of the different branches below FGC13411.

The FGC13411 sub-branch of the L513 portion of the Y-Haplotree

Turning to the L513 Haplogroup Project, the Administrator Mike Walsh has produced an excellent diagram of the various branches of this particular subgroup and you can view it and download it here. Mike's version incorporates more data than the Big Tree diagram above.

The FGC13411 portion of Mike Walsh’s experimental L513 Descendant Tree (version Mar 25, 2017).
The current version is maintained at
Use permitted courtesy of Mike Walsh. 

Interestingly, most of the names below FGC13411 (top left of the diagram above) appear to be of Irish origin, with some being assigned to "Ireland West" (Butler, Scanlan, Sears, Scott, Anglin, Breen), some being assigned to "Ireland North" (Roddy), and some to both (Devine, Dever, Devins). Possibly the most interesting name among this group is Butler, a well-known Norman name. The Butlers of Ormond held sway over large parts of Munster during the Middle Ages and their castles are still evident to this day. In fact, I visited one just last week!

Me in front of Cahir Castle - owned by the Butler's from 1375 to 1961


There is little doubt that these two matches form a new genetic family within the project. Several questions remain however: where did they come from? and are we seeing the genetic signature of the Imokilly Gleeson's?

Their genetic signature is quite unique and separate from the North Tipperary Gleeson's of Lineage II.  There is good evidence from their respective genealogies that their Gleeson ancestors go back to Cork in the early 1800s. But as the two individuals are very closely connected, could we be looking at a relatively recent DNA switch (NPE**) within the last several hundred years in this particular Gleeson branch? It certainly is a possibility. Only by recruiting additional Cork Gleeson's can we further elucidate how long the Gleeson name has been associated with this particular DNA signature, and whether or not it goes back to the original Imokilly Gleeson's of the 1100s. 

The surnames of their matches are an interesting array of rather unusual names, some of them originating in Scotland, others in the north of Ireland, and few (apparently) from the Cork area. The project administrators of the relevant haplogroup projects and geographic projects might be able to throw some more light on this.

The SNP marker analysis suggests a pretty exact position on the Y-Haplotree (i.e. somewhere below FGC13411) and further SNP testing with the R1b-S6365 SNP Pack (or Big Y) should help clarify this. But the mixture of Scottish and Irish surnames associated with this particular portion of the Y-Haplotree is not currently illuminating.

So overall, we could be looking at the genetic signature of the Imokilly Gleeson's ... or we could be looking at a relatively recent DNA switch within the last 200-400 years. Hopefully we can recruit more Gleeson's from Cork and the nature of this new genetic family will become more clear over time. Nonetheless, this is an important and exciting advance for the DNA Project.

Maurice Gleeson
March 2017

(1) The Pipe Roll of Cloyne. JCHAS, 1915, Vol. 21, No. 107, page(s) 136-­145 ... the territory of Oglassyn is mentioned on page 143. I need to dig out the specific reference to the Gleeson's being local land stewards.

* for added security and privacy, the ID number consists of the individuals initials and the last 4 digits of the kit number. The G numbers used on our WFN website are also included.

** NPE, Non-Paternity Event, refers to a Surname or DNA Switch (SDS). The causes of such a switch are manifold and may include adoption, legal name change, a young widow remarrying, infidelity, illegitimacy, social climbing, swearing of allegiance, etc. See the video below from 6:30 onwards for a full explanation.

Here is a the video that explores if the DNA evidence supports what we know of the origins of the Gleeson surname from historical texts and documentary evidence. The section that deals with the Imokilly Gleeson's starts at 21:25.  


  1. Well done Maurice. This must have taken some time. Very interesting how the same surname was adopted in the past that are often not genetically connected. A few years ago I wouldn't have guessed.

  2. This is exciting news! Thank you to all involved and especially for the great blog!

  3. I believe my Gleeson (Gleason) line is of the Cork Gleesons. My great-great-grandfather Patrick Gleeson's wife was Katherine "Kate" Donoghue (Donohue, Donohoe). My great-grandfather emigrated to the U.S. from Rathcormac in County Cork. Elsewhere Bartlemy is indicated as his birthplace. I'd be very interested in learning more about this line of Gleesons.

    1. I see you have just joined the DNA Project, Laura - you are very welcome. Hopefully you will find some close relatives who can help you with your research. I will email you shortly.