Many Irish clans now have yDNA surname projects. These are based on the inheritance of the yDNA chromosome down through the paternal line. This kind of project is ideally suited to families bearing Irish patronymic surnames as the yDNA results generally reflect the surname.

The goals of Irish yDNA surname projects usually include the primary one of finding of relatives in Ireland. The goals sometimes include the desire to verify paternal ancestry and the identification of place of origin of the family. A history of the clan and its various branches can also be part of the goals of Irish Surname projects.

It has been the case for years that "Irish" yDNA Surname Projects have attracted people from many countries but they held little interest for the Irish who were still resident in Ireland. The argument has been that Irish who live in Ireland “know where they come from” and don’t need to do DNA tests.

However, Irish yDNA Surname Projects really need Irish-based participants to get involved in yDNA testing, for several reasons:

Irish-based families may wish to connect with relatives, who may have emigrated in times past, where there is no paper trail or living memory to help with making these connections. How many people in Ireland can say “most of my family emigrated in the Famine and we have no idea where they went or who their descendants are”. Or “we have no contact with branches of our family who left Ireland a long time ago”. Must this be the case? DNA can open doors for the Irish who have lost track of relatives.

Also, if more Irish men were involved in yDNA Surname Projects it would help the Irish diaspora who need yDNA results of Irish-based participants, to serve as "benchmarks" in their genealogical research. It is an exciting way to bridge the gap between the sometimes sad lonely emigration of the past and the modern world of global communications.

There are many commercial DNA companies which do yDNA testing. Those clans which are members of the Clans of Ireland, and have DNA projects going on, are listed below. If you click on a surname project link it will take you to the information about that particular project and give details of what is involved.
We encourage interested Irish clan members to look for their own surname DNA Project but if none exists for their surname, note that the Ireland yDNA Project caters for all Irish surnames. The Ireland yDNA Project website is at:


Please note that the science of DNA is still evolving and that membership of an Irish Clan is based on one's inherited and chosen identity and not on bloodline descent alone.

You can read more about Irish Surnames and Genetic Testing: a Developing Science here

The following registered Irish Clans have DNA projects in progress:


(O’) Boylan Clan

Project Administrator: Email

DNA Webpage


O'Brien Clan

Project Administrator: Mr. Dennis O'Brien


DNA webpage:


O'Byrne Clan

Project administrators: Mr. Paul Burns1 and Mr. Nicholas Burns2

DNA webpage


McCabe Clan

Project administrator: Dr. James M. Freed

DNA webpage see Register of Clans


Cassidy Clan

Project administrator: Mr. Glen Perdue

DNA webpage: see Register of Clans


Crowley Clan

Project Administrator Catherine Crowley Budd.

Email and DNA Webpage: see Register of Clans


Curtin Clan

Project administrator: Mr. Dan Curtin, 45 Bishop Nelson Road, Valatie, NY US 12184, phone 518-758-9480. Website:

Dalton Clan

Project administrator: Michael Dalton

Email/DNA webpage: See Register of Clans


O’Dea Clan

Project administrator: Mr. Shane O’Dea, 45 Carysfort Park, Blackrock, Co. Dublin, Ireland Mobile 087-7789034

Website/Email: See Register of Clans


O'Donnell Clan

Project administrator: Mr. Vincent O’Donnell:

Email: See Register of Clans


O'Donoghue Society

Project Administrator: Ms Elizabeth O'Donoghue


DNA Webpage:see Register of Clans


O'Driscoll Clan

Project administrator: Mr. Colin Ferguson


DNA Webpage: See Register of Clans


Egan Clan

Project Administrator: Sue Egan




Flanagan Clan



Flood Clan

Project administrator: Mr. Kevin Flood




O'Gara Clan

Project administrator: Mr. Joe O'Gara

Website: See Register of Clans


MacGeoghegan Clan

Project administrator: Mr. James Geoghegan 

Email: See Register of Clans


McGrath Clan

Project Administrator: Dan McGrath

Webpage / Email: 


O’Haran Clan

DNA webpage: See Register of Clans


O'Higgins Clan

Project administrator: Dr. James O’Higgins Norman



Hosey/Hussey Clan

Project administrator: Mr. Robert b. Hosey

Email  DNA Webpage: See Register of Clans


O’Kane Clan

Project administrator: John A O’Kane

Email: See Register of Clans


Kavanagh Clan

Project administrator: Email:See Register of Clans


Kyle Clan

Project Administrator: Ms Pam Rooney

Email: See Register of Clans.


Larkin Clan - Muinter Lorcán

Project administrator: Brad Larkin

Email:  DNA webpage: See Register of Clans


McGillycuddy of the Reeks

Project administrator: Dr. Brian McEvoy, Trinity College, Dublin.


MacMahon Clan

Project administrator: Michael Mitchell



O Mahony Clan

Project administrator : Dr. Finbar O Mahony,

DNA webpage Email:


(O’) Molloy Clan

Project Administrators:  Thomas Molloy and John P. Malloy



McMullen Clan

Project administrator: Lt. Col. Lyn McMullen  Email: 

DNA webpage:


Mulvihill Clan

Project administrators: Mr. James M. Mulvihill:

Mr. Aiden Mulvihill Email:


O'Neill Clan

Project administrator: Sean O'Neill

DNA webpage: See Register of Clans


Nelligan Clan

Project administrator: Megan Smolenyak Smolenyak,



Roche Clan

Project Administrator: Dr. Peter Roche



O’Shaughnessy Clan

Project adminstrator: Desmond O’Shaughnessy



O'Shea Clan - Ó Séaghdha

Project Administrator:  Mrs Margaret Jordan



O’Sullivan Clan

Project administrator: Shanna Sullivan Jones



Tierney Clan

Project administrator: Mr. Cahir Tierney



Weadick - Mac Mhadóc

Website: See Register of Clans