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November 2014

The revised phylogenetic tree (until the FTDNA site is updated) is as follows:

Our FGC11134 list is now: see ISOGG 2014 Y-DNA Haplogroup R

ISOGG 2014 Y-DNA Haplogroup R
Y-DNA Haplogroup Tree 2014
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• • • •  • • • •  • • R1b1a2a1a2c1c   FGC11134
• • • •  • • • •  • • • R1b1a2a1a2c1c*   -
• • • •  • • • •  • • • R1b1a2a1a2c1c1   L96
• • • •  • • • •  • • • R1b1a2a1a2c1c2   CTS4466/S1136
• • • •  • • • •  • • • • R1b1a2a1a2c1c2*   -
• • • •  • • • •  • • • • R1b1a2a1a2c1c2a   A541
• • • •  • • • •  • • • •  R1b1a2a1a2c1c2*   -
• • • •  • • • •  • • • •  R1b1a2a1a2c1c2a1   S1121
• • • •  • • • •  • • • •   R1b1a2a1a2c1c2a1*   -
• • • •  • • • •  • • • •   R1b1a2a1a2c1c2a1a   L270.2
• • • •  • • • •  • • • • R1b1a2a1a2c1c2b   A212, A218
• • • •  • • • •  • • • • R1b1a2a1a2c1c2c   A663
• • • •  • • • •  • • • R1b1a2a1a2c1c3   A286

June 2014

The projects continues to expand. Two new participants joined the project at the O Mahony Gathering at Gugane Barra and they have since been joined by some transfers from other DNA testing companies. 

April 2014 

Two Big Y results have been returned in the past week. These are for kits #115485 and #165440 and the have lead to some significant developments for the project. So we can now add to CTS4466+ SNP the additional, newly discovered SNPs A150 and S1121+, to the tree. It is possible that the SNP A150 is a distinctive marker for this branch of the O Mahony sept but more will be revealed as the testing continues.

The number of participants continues to increase although the rate of increase has slowed in the past year. We have a new member from the Netherlands and it is good to see participation from the continent of Europe. Hopefully we will soon be joined by O Mahony family members from Continental Europe.

 6 April 2013

The number of participants continues to grow and it is encouraging to see that we have 106 sets of results on the spreadsheet with others in the process at the laboratory.

The phylogenetic tree shown above has continued to develop and has been modified yet again in the past few days. These changes are based on the efforts of the "citizen  scientists" (participants like ourselves) who have contributed their samples and made them available for analysis.  

January 2013


Note : Kit # 115485 mentioned below is that of  an O Mahony project member , so read please on -

The following excerpt from an email from Nigel McCarthy, co-administrator of the Munster Irish project, explains the discovery of a new SNP associated with R-L21:

"[R1b-L21-Project] Placement of CTS4466 and CTS5714 on the L21 tree.

Kits 115485 and N59178 have about 9 and 13 markers respectively (out of 111)
showing mutations away from ancestral Irish Type II.  However not one of
these do they share. This suggests to me that CTS4466+ and CTS5714+ likely
occurred no later (and most probably before the progenitor of ancestral
Irish Type II was born, which I believe some of you have estimated as around
400-500 A.D., and that (almost) all 1511-T2 would test positive for these
two new SNPs.
Nigel McCarthy "

We can look forward to the modification of the Phylogenetic Tree to take account of this and other SNPs that have been found since the Geno 2.0 project results have started coming in. 

There are a number of O Mahony men who currently show R - L21 as their terminal SNP but it is now possible to order a specific test for CTS4466  and a number of other downstream SNPs. The Phylogenetic Tree keeps on developing as the research continues.



August 2012

Those participants who have tested at Deep Clade level and who are positive for R L21 may wish to test for SNP DF 13. 

June 2012 update


The Atlantic Modal Haplotype (AMH) is the most commonly found haplotype on the Atlantic fringe of Europe. It corresponds closely with subclade R1b1a2a1a. The O Mahonys who trace their origins to West Cork as far as Mizen Head share this haplotype.

South Irish Type II  (R1b1a2a1a1b4): Of the participants who have tested at the Deep Clade level we now have 18 who are confirmed as R1b1a2a1a1b4.  This is the majority Haplogroup within the project. Irish Type II is evident also with many other names of both Irish and English language origin – most of the latter of which have been derived only in more recent times – it seems feasible that the Irish Type II  ...... O’Mahonys,O’Sullivans, O’Donoghues, and McCarthys may all have a common ancestry in a powerful figure in the Eóghanacht hierarchy. 

Some exceptions within the O Mahony sept are as follows:

The R1b1a2a1a1b4b NW Irish 

The R1b1a2a1a1b4b branch of the Y-DNA tree is defined by a single nucleotide polymorphism (SNP) called M222. This diagnostic marker is associated with many individuals whose roots lie in the counties of Northwest Ireland, Ulster and Lowland Scotland. In no county is this pattern the dominant DNA profile, but in some counties (Donegal in NW Ireland, for example) it approaches 20 percent.

A2-Leinster: R-L159.2(R1b1a2a1a1b4f): Although there are few within our project who belong to this sub-group currently, it deserves future research to establish when it entered the sept/clan. Perhaps this is a challenge for the historians of the Society.

IrishType III (R1b1a2a1a1b4h): Irish Type III in the O’Mahony yDNA surname project seem to be mainly identified with the border areas of North Cork and Co. Limerick and South Tipperary.

R1b1a2a1a1b4i (where the "i" indicates the presence of the marker P314.2+). "This is haplotype is associated with branches of the Eoghanachta e.g.the McCarthys and Sullivans.

The other surnames involved in the P314.2 lineage are predominantly Irish (though with low representation from Leinster), and Scottish.

The frequent occurrence among McCarthys is not reflected in other Munster surnames: O’Sullivans and O’Mahonys each have about 3%  P314.2 lineage and there are no O’Donoghues at all in the FTDNA O’Donoghue Surname Study, although there were one from Munster and one from Leinster in the 2003/2004 Trinity College, Dublin Project.(N. McCarthy, 2012). For a full treatment of this haplogroup see the McCarthy surname project on FTDNA.  (Nigel McCarthy).

April 2012:

The number of upgrades ordered since December 2011 continues to be very encouraging and quite a number of participants also upgraded to the Deep Clade test before the restructuring of FTDNA pricing came into effect. 


Project News: December 2011

Many thanks to those who contributed to the General Fund and to those who sponsored kits before the General Fund was set up. Our gratitude is also due to Paul and Gloria for their continued work in producing the Cladogram and Split Tree Diagrams.  “Well done” to all those who have upgraded to the 37 or 67 marker level. Participants who have opted for Deep Clade Testing will see the fruits of their efforts in the pie chart of haplotypes shown later in this brief report. These efforts have allowed us to see how our members results have fallen into categories and how they relate to the Phylogenetic Tree; many members are classified as M269, others as L21 and still others as P314.2 and159.2:

Figure 1. The Phylogenetic Tree.

The majority of 95 men tested for the O Mahony Society project have been categorized as haplotype R-1b1a2  (M269). Further refinement through additional testing could indicate a more precise place on the phylogenetic tree for these men. This will allow us to see whether members of that group turn out to be L21or other “descendant” branches of the tree. The summary of the project results so far can be seen below:

R1b1a2a1a1b4 (AMH not grouped) (more research needed):                    20 participants

R1b1a2a1a1b4 (AMH subgroup DYS607=14) :                                             5 participants

R1b1a2a1a1b4 (AMH subgroup DYS607=17):                                              5 participants

R1b1a2a1a1b4 (AMH subgroup DYS607=18):                                            14 participants

R1b1a2a1a1b4 (Irish 2 not grouped):                                                           11 participants

R1b1a2a1a1b4 (Irish 2 SubGroup DYS442=13):                                           7 participants

R1b1a2a1a1b4 (Irish 2 SubGroup DYS442=13; DYS447=22):                    11 participants

R1b1a2a1a1b4b (M222: Irish 1):                                                                    4 participants

R1b1a2a1a1b4f(R-L159.2: Leinster):                                                             2 participants

R1b1a2a1a1b4h(L226: Irish 3):                                                                    10 participants

R1b1a2a1a1b4i (P314.2):                                                                               3 participants

Various Other Haplogroups:                                      3 participants who are “exceptions”   

More will be revealed about the structure of the sept in the project by further testing of additional participants.


AMH : The Atlantic Modal Haplotype (AMH) is the most commonly found haplotype on the Atlantic fringe of Europe. It corresponds most closely with subclade R1b1a2a1a(1) [L11]. The O Mahonys who trace their origins to West Cork as far as Mizen Head share this haplotype unlike the main body of the sept who are Irish Type II.

Irish Type II (South Irish) (R1b1a2a1a1b4): This is the haplotype that we would expect most of the participants to belong to. So far, this expectation has been borne out by the results of the testing programme.

A2-Leinster: R-L159.2 (R1b1a2a1a1b4f) : Although there are few in this sub-group within our project currently, it deserves future research to establish when it entered the sept/clan.

IrishType III  (R1b1a2a1a1b4h): Irish Type III in the O’Mahony yDNA surname project seem to be mainly identified with the Mitchelstown/Kilbehenny and related border areas of North Cork and Co. Limerick. The Irish Type III are described as Dal Cais.

A1-P314.2 ( R1b1a2a1a1b4i) : This is also an exception that one would not expect to encounter in the O Mahony project although it is associated with branches of the Eoghanachta e.g. the McCarthys and Sullivans.

Note:The O’Mahony sept are descendants of the Eoghanacht  Rathlind, as are the O'Donoghues. The name  O Mahony should appear just next to the ODonoghues on the diagram below. Note also the dotted line from Eoghan Mor to Cas from whom the O Briens and Kennedys descend. This latter branch is classified as Irish type III whereas the Moriartys, O’Kirbys, McCarthys, McGillacuddys/Sullivans, O’Keefes, O’Donoghues and O’Mahonys are classified as Irish Type II/South Irish.


Illustration from the "Genetic Investigation of the Patrilineal Kinship Structure of Early Medieval Ireland" by Brian McEvoy, Katharine Simms, and Daniel G. Bradley.  Published in the AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY.



Project collaboration pages:
·  I2b
·  Irish Type I
·  Irish Type II
·  R-L21 South Irish Project
·  Irish Type III
·  Irish Type IV
·  The Ireland yDNA Project
·  R1b Eo'ganacht septs project

Graphs were produced using Network © Copyright Fluxus Technology Ltd Median Joining feature by Bandelt H-J, Forster P, Röhl A (1999), and MP feature by Polzin T, Daneschmand S V (2003) , or using SplitsTree4, by D.H. Huson and D. Bryant, Application of Phylogenetic Networks in Evolutionary Studies, Molecular Biology and Evolution, 23(2):254-267,2006 with data calculations as derived using the fabulous McGee Utility by Dean McGee; Spreadsheets built with Microsoft Excel 2010