THE O MAHONY SOCIETY

 

Surname yDNA Project

Project launched 1 August 2003 < Page revised 7 September 2009 < Page updated 7 Septmember 2009

 

Origins of the O Mahony Surname

 

There are a great many O Mahonys in Ireland—the name is included, usually without the prefix O, among the hundred commonest surnames.  It belongs almost exclusively to West Munster.  The vast majority of Mahony and O Mahony births are registered today in Co. Cork, the area historically associated with the clan.  O Mahony chieftains were powerful, often described as princes.  Their principal territory comprised the modern barony of Kinelmeaky and extended to the sea, with some fourteen castles on the coast of southwest Cork.  The name O Mathghamhna—in modernized spelling O Mathuna—is derived from Mathghamhain (Irish for bear), the grandson of Brian Boru.  Mathghamhain was killed, with many more of the Desmond fighting men, at the Battle of Clontarf in 1014.  (Edward MacLysaght, Irish Families and Diarmuid O Murchadha, Family Names of County Cork)

 

All male O Mahony descendants, regardless of race, ethnicity or the precise spelling of their last name, are welcome and encouraged to participate in the O MAHONY Surname DNA project.  The project analyses the Y-chromosome to determine kinship.  Men inherit both their Y-chromosome and their surname from their fathers; and pass both on to their sons.  Women do not have a Y-chromosome, and traditionally adopt their husband’s surname.  Therefore, female descendants are only able to participate in the O MAHONY Surname DNA project through a male O’Mahony relative.

 

JOIN THE PROJECT TODAY TO SEE YOUR ANCESTOR REPRESENTED!

 

 

Project Background

 

The O MAHONY Surname DNA project was begun on 1 August 2003 by Perry Streeter and was transferred in early 2007 to the O Mahony Society for ongoing administration.  It is currently administered by James Castellan.

 

Geneticists can now study the Y-chromosome DNA of males bearing all variations of the O MAHONY surname to determine whether or not they are related and the approximate degree of their kinship.  For an excellent explanation of this process, please see DNA 101 at the BLAIR DNA Project.

 

Using an ethical and competent testing company, Family Tree DNA, we are creating an O MAHONY Surname DNA database.  To address any concerns that you may have about privacy, please click here.  To collect a DNA sample, a simple, painless cheek-scraping test is used instead of a blood test. View a video of cheek swabbing process.

 

Be aware that DNA testing can also reveal secret adoption or maternal infidelity anywhere in a lineage.  Consequently, any O MAHONY male who tests his DNA should be prepared for the small possibility that he may not be an O MAHONY, genetically speaking.

 

Project Objectives

 

  • Identify how many distinct O MAHONY family lines originated in Ireland.
  • Determine whether or not O MAHONY Irish emigrants to a given country were related to each other.
  • Enable a living male O MAHONY anywhere in the world to possibly identify his family’s O’Mahony sept/branch of origin.

 

We are especially seeking participants who are descendants of the following septs/branches of our Clan and financial assistance may be available for those with financial need. Please email James Castellan for more information.

 

  • Fenian founder John O’Mahony’s family from Kilbehenny area.
  • Eoin “The Pope” O’Mahony’s family.
  • O’Mahony an Oir descended from Teig an Oir O’Mahony who lived ~1300 A.D. from Kilmichael area.
  • O’Mahony Ban descended from Liam Mor Ban who lived ~1750 (possibly using surname White now).
  • O’Mahony Fineen a.k.a. O’Mahony Ceitherne or Kearney/Clann Finghin na Ceitherne, descended from Finin O’Mahony of Rosbrin ~15th century, located in the eastern part of West Muskerry.
  • O’Mahony Ruadh descended from Donagh Ruadh O’Mahony, a.k.a. O’Mahony Roe, Clann Finghin, Mahony Ruas.
  • O’Mahony Connor called Clann Concobhor descended from Concobhar O’Mahony ~1350 that occupied Kilmurry and Kilmichael area.
  • O’Mahony Caol descended from Fingin Caol of Laemcon Castle ~1500 in the west Cork area.
  • O’Mahony Kilnaglory descended from Donal, son of Diarmuid II who died ~1327, and fled and settled in Kilnaglory near Ballincollig.
  • O’Mahony Mergeach descended from Teig Meirigeach O’Mahony who died 1565.
  • O’Mahony Laidir to which Canon John O’Mahony belonged who descended from Sliocht Meirgeach, possibly in the Kilmurry and Barryroe area about a hundred years ago.
  • O’Mahony Bui who had a family member participate in the 1792 rebellion.
  • O’Mahony Kean a.k.a Keane and Cian who often used the surname Kean Mahony.
  • Dromore, Co. Kerry, O’Mahony family.
  • O’Mahony Dubh associated with the family ancestral home Cuil an Doirin, Ros Chairbre.

 

Project Results

 

Initial test results for this very small sample suggest that all O MAHONY descendants do not share a common ancestor as several of the columns for distinct markers have different values indicating a genetic difference between the individuals. To see the various reports summarizing the results go to

 

            O’Mahony Surname Project Participants’ Results Reports

 

 

Go to “Quick Interpretation Guide” for help understanding the technical details of how to derive meaning from differences in the numbers found in the tables.

 

A larger number of participants are needed before we expect to see more distinct family clusters forming. In time we hope to identify members of each cluster who are documented as being from specific areas of Cork and Kerry. Join now.

 

 

How to Participate in the Project

 

If you are a direct-line male O MAHONY descendant and would like to have your DNA tested for matches with others, simply click on the following link… http://www.familytreedna.com/group-join.aspx?Group=OMahony

 

 

            O’MAHONY Surname Project at Family Tree DNA

 

 

            As a project participant, you will be eligible for a discounted test price of:

        $209 for a 67-marker test (ideal, one can always upgrade later for additional $$)

        $119 for a 37-marker test (recommended)

          $99 for a 12-marker test (discouraged, used primarily for variant spellings to rule out O’Mahony link)

plus a small fee for shipping & handling and return postage.

 

 

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