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About us

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 analyzes 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.

Project Objectives

Identify how many distinct O MAHONY family lines originated in Ireland.
Determine how O MAHONY Irish emigrants to a given country are related to each other.
Enable a living male O MAHONY anywhere in the world to identify his Irish family of origin.


Donations to the Group General Fund will be used to sponsor participants who have Irish ancestry that the O'Mahony DNA Committee feels will help reach our project goals.