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Genetic Genealogy Project

Welcome to the genetic / historical study of Clan Donald USA.


If you are mostly interested in getting a new DNA test, go to our testing page.


Clan Donald’s DNA project, now almost 20 years old, is among the largest family-based genetic genealogy project in the world. It has now reached the 3000 total participant level.

In March 2004, Clan Donald Genetic Project announced a 25-marker signature for identifying descendants of Somerled, ancestor to many MacDonalds, MacDougalls, and MacAllisters, including our Clan Chiefs. Somerled was an important figure in the history of the western highlands of Scotland. He died in battle in 1164 while attacking Glasgow with 160 ships drawn from his own territories and from Dublin. His descendants controlled much of the west coast of Scotland and the Hebrides for more than 500 years.This website now identifies a 111-marker signature of Somerled and, with the express permission of our chiefs, shows the mutation of various key lines within the worldwide leadership of Clan Donald. For a discussion of Somerled's ancestry see Before Somerled.

The webmaster for these genetic project pages is Professor J. Douglas McDonald, of the University of Illinois, who is a project co-administrator. The project originator and co-author of this webpage is Mark MacDonald, former National Historian for Clan Donald U.S.A. and head project administrator.

Mark initially conceived this project in the summer of 1999 when reading a Wall Street Journal article in which Y-chromosome markers were being used to trace the ancestry of the priestly class of Israel back toward a single source, historically identified as Aaron, brother of Moses. Since Clan Donald in Scotland and Ireland had its own diaspora in which our ancestors emigrated either voluntarily or by force around the world, he wanted to create a project which could both help individual clan members who could trace to the waters edge 200 to 250 years ago but could not cross the water, and provide a means for testing the accuracy of various parts of the history of Clan Donald, the clan’s descent from Somerled, its relationship to the Scottish kingdom of Dalriada founded before 500AD, its relationship to Colla Uais, High King of Ireland circa 330AD and its relationship to both the O’Neills high kings of Ireland and their O’Donnell cousins.

In 2004, we issued a press release containing a 25-marker signature of Somerled which not only demonstrated that he was of Norse paternal descent but which strongly pointed to Norway for his recent ancestors. This signature began 13-25-15-11-11-14-12-12-10-14-11-31-16-8 (in the marker order used by Family Tree DNA), though we now believe that signature originated with his 3rd great grandson John, first Lord of the Isles, and that Somerled himself was 15 rather than 16 at the next to last marker above. We now believe that Somerled's signature for the complete 111 marker Family Tree DNA panel set is:
13 25 15 11 11 14 12 12 10 14 11 31 (12 marker panel)
15 8 10 11 11 23 14 20 31 12 15 15 16 (25 marker panel)
11 12 19 21 17 16 17 18 34 39 12 11 (37 marker panel)
11 8 17 17 8 12 10 8 11 10 12 22 22 15 11 12 12 13 8 14 23 21 12 12 11 13 11 11 12 12 (67 marker panel)
29 15 9 15 12 27 27 19 12 12 12 12 10 9 12 11 10 11 11 31 12 13 24 13 (continued on next line)
9 11 19 15 19 11 23 14 12 15 24 12 23 19 10 15 17 9 11 11 (111 marker panel).
As discussed below, we now know SNP markers that delineate descendants of Somerled. The marker CLD56 likely originated in Lord John's father (Angus Og) or Lord John himself. The marker YP326 (FGC11892) is the most likely one to have originated with Somerled himself, though its exact timing is uncertain. The marker YP327 (8391799) was almost certainly positive by Somerled's generation.
See DNA Explained for an explanation of genetic signatures and SNPs. To see how we deduced Somerled's DNA profile see After Somerled.

When we began this project, there was great hope that we would be able to tell from DNA what Clan subgroup a participant is from, for example, Sleat or Glengarry. This has proven to be impossible for almost all people using only STRs.. We have however found an STR profile that clearly identifies descendants of one particular person, James MacDonald 1st of Castle Camus. DNA technology improvements, especially the "BigY" test introduced by FamilyTreeDNA have now produced new markers that indeed do identify Clan subgroups and family groups within our "Somerled" related people. These markers, unlike most of the ones defined above, are definitive. They have also corroborated the timeline of the Somerled genealogy discussed later. The results are discussed at our BigY results web page.

In February 2004, this project had announced another important Dalriadic ancestral genetic signature which we had identified as the signature of “Colla Uais, father of Dalriada.” The kingdom of Dalriada was the predecessor to the medieval kingdom of Scotland. This signature which begins 13-24-14-10-11-14-12-12-12-13-13-30-18, has subsequently been recognized as the modal or near-modal in the very large "Haplogroup" delineated by the SNP marker L21 and as such cannot be attributed to just one man, though he likely bore it.

Clan Donald has historically associated itself with Clan Colla in Ireland named for the three Colla brothers who allegedly conquered Ulster in 330AD and whose descendants had created a kingdom called Oriel with holdings spread throughout Ulster from Derry through Cavan and Fermanagh in Ireland. We will explain below why that initial identification appears to have been in error but which still leaves Clan Donald heavily descended from the founders of Scottish Dalriada and from Colla, as well as Somerled. This combined analysis of genetics and history is not an “official” history of Clan Donald but rather a statement of our current best theories how to tie the data to the history.

This finding coupled with extensive discussions with Irish historians who strongly assert that Cairbre Riada grandfather of Fergus, Angus and Lorne was not descended from Colla Uais, has led to a shift of this interpretation concerning the probable source of various groups within Clan Donald. Mark still believes that the Dalriadic royal line carried the “Colla” genetic signature but that the source of our descent from Clan Colla comes through Irish followers of Godfrey MacFergus. Click Other Ancestry for this historical analysis of the non-Somerled part of the Clan Donald.

Subsequently research by Moore et. al. at Trinity College Dublin [Moore 2006] identified the signature of Neill (Niall) of the Nine Hostages who was considered to be a paternal line cousin of Colla Uais. The “Neill” line belongs to the signature 13-25-14-11-11-13-12-12-12-13-14-29 which is strongly concentrated in northwestern Ireland. It is delineated by the SNP marker M222. It, like the purported Dalriadic line, is so large that though it bears a published academic imprimatur it clearly is far larger than just Niall descendants.

In addition to our discoveries concerning the medieval history of the Clan Donald, the DNA results allow us to make some statements about where our ancestors were living long ago, even during the Ice Ages. These are discussed in Prehistory.

We are still trying to match DNA profiles to known genealogies, though we have had very limited success. If you are a DNA participant and have known Clan ancestors you are strongly urged to submit a Gedcom or paper genealogy to the Clan Donald USA genealogist, whose email address is , including a note giving your Clan Donald DNA project code. If your genealogy connects anywhere to the chart on the "After Somerled" web page, please contact the DNA project webmaster as well.


Clan Donald DNA Website version 3.26, Oct 1, 2020.

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