& Other Variations

Mc, Mac, and O'

In October 2002, I posted a question to GENEALOGY-DNA-L at RootsWeb, a site frequented by many surname project managers, asking if I should encourage participants with Mc, Mac variations; the responses are below.

Yes, you should include them. Mac meant son of, and O' meant grandson of.

In the Mc/Guinness survey we included names that should have matched and were said to derive from MacAonghusa (pronounced nearly like Mac-a-nee-sa). These included Maginnis, MacNiece, McCreesh and Neeson, and sure enough there are dna-similarities across these surnames.

Differences arose in transposing Gaelic-era surnames into English. To anglicise their names, many also 'dropped the Mac', like my ancestors.

Ronald Reagan is descended from O'Riagains who dropped their O'.
'Kennedy' came from O'Kennedy, originally O Cinneide. Both are pronounced a little differently in Gaelic.

Such changes were most common between 1600 and 1800, and English spelling itself was a moveable feast until 1750-1800. Gaelic spellings also changed over the centuries.

Many Irish emigrants to the USA after 1800 also had their surnames mangled on arrival. Thousands landed not speaking English, so they couldn't correct or improve their newly-rendered name. Hence O'Hagan became 'Agin', etc.

The best web page on Irish surnames, their variants and where most were living in the recent past (mid-1800s) is at -http://www.ireland.com/ancestor/index.htm

List the range of surnames linked to yours and prepare for some unlikely variants.

 Patrick Guinness


That's good advice. In our Rea Surname DNA Project, we're also including not only all variant spellings of Rea, but also MacRaes, since the name Rea is a sept of MacRae.

[sept or sect refers to a clan, tribe, or family, proceeding from a common progenitor]


Surnames behave as alleles (variants) in a locus carried by the Y chromosome.

Here is a text published in the Mensa International Journal by Kate Nacard (kate@au.mensa.org is Chairman of Australian Mensa):

Surnames are usually passed down the family line by way of the father's family name and are derived of many sources including Christian names (Francis), occupations (Carpenter), places (Forest), animals (Fox), colors (Black), and quantities of mind or body (Bright, Little).

Often the Christian name and a form of the word "son of" added to it constitute the new family name (Donaldson, Adamson). In England and Ireland, "son of" is often "Fitz" (Fitzgerald) [cf the French (Norman) "fils", pronounced "fiss"], while in Wales "ap" or "ab" (each in lower case) denote "son of" (Dafydd ab Edmund). Eventually, the "ab" and "ap" were shortened to "b" or "p" and hence Broderick, Pritchard and Bellis appeared. Welsh names were also formed by adding "s" [the mark of an ancient genitive] to Christian names as in Jones, Roberts and Philips.

In the Scottish [yes: Scottish] Highlands, "Mac" indicating "son of" is very popular (MacDonald, MacWilliam), but if the letter following the "c" of the "Mac" is not capitalized, then the latter part of the name is not a Christian name but instead has an occupational derivation, eg, Macnab (son of the abbot), Macintyre (son of the carpenter) and Macpherson (son of the parson).

In Ireland, "son of" is usually "Mc" (McAdam), but it's interesting to note that at one time in Ireland the head of the clan was the grandfather and thus we have O' (from Ogha meaning grandson of) Brien, O'Donnel and O'Neill.

Yves Pauplin


I don't know whether you should encourage or not, however if you consult any good book of Irish surnames you will find that originally almost all native Irish surnames had the prefix Mac (meaning son of) or O (meaning descendant of) (Mc is an English short form of the Gaelic Mac used by scribes). During British occupation of Ireland many Irish surnames had the prefix hacked off, and the rest of the name either respelt according to how it sounded to the English ear or even (mis-)translated into English.

Thus, Kinney and M(a)cKinney is really the same surname. Best of luck,

Bert de Friest Macnamara


Georgia Kinney Bopp
Revised 25 November 2002