About us
The names Leary and O'Leary seem to have originated over 1600 years ago in Ireland: O'Laoghaire, O'Laohaire, O'Laoire, but its use as a clan name and then as a surname are more recent. Genealogy expert Ed MacLysaght said in his 1957 'Irish Families': "The town of Dún Laoghaire, a suburb of Dublin, is named after a King of Ireland named Laoghaire at the time of St. Patrick in the fifth century; but this, of course, has no connexion with the surname formed... centuries later (9th century at the earliest). In Irish O'Leary is O Laoghaire."
Before DNA results shed light, a single origin of all Learys sounded logical, but genetic genealogy now knows there are at least 22 lineages whose common ancestor preceded the 9th century-beginning adoptation of personal surnames; sometimes by 10s of 1000s of years. The primary O'Leary lineage uses code for Y-DNA mutation sequences because its roots are before surnames, and that sequence code is R-M269 >... DF13 > FGC11134
Before DNA results shed light, a single origin of all Learys sounded logical, but genetic genealogy now knows there are at least 22 lineages whose common ancestor preceded the 9th century-beginning adoptation of personal surnames; sometimes by 10s of 1000s of years. The primary O'Leary lineage uses code for Y-DNA mutation sequences because its roots are before surnames, and that sequence code is R-M269 >... DF13 > FGC11134
Y-DNA's main task is determining biochemical Y-DNA identity so as to match others by lineage sequence, and to demonstrate non-matching.