The MacLeod surname project was started in 2004 by the Associated Clan MacLeod Societies (ACMS). Since then, our understanding of the genetic makeup of the clan has evolved dramatically. In the early years, the Y-DNA test results showed that the clan was genetically diverse, like many other clans. Soon after, one subgroup of testers emerged as the possible 'founder' subgroup, particularly amongst MacLeods who carried the R-L165 mutation. With the advent of Big Y testing, we are now confident that the SNP R-BY3210 represents a man born at or near the start of the clan and may have first appeared in Leòd, the progenitor of the clan. Furthermore, the later SNPs FTT137 and FTT138 correspond to the well-established split of the clan into the Harris & Dunvegan and Lewis & Raasay branches. In addition to this founder subgroup, 4 other groups of MacLeods have emerged representing descendants of people who likely assumed the MacLeod surname far back in time. We learn something new with each new test result and so we heartily welcome new MacLeod testers! The MacLeod surname project is open to males with the surname MacLeod in any of its various spellings. A DNA test is required for participation, but our focus is specifically analyzing Y-DNA test results. If your order a DNA test kit, please include the birth location and details of your earliest known paternal ancestor in the 'genealogy' settings, and it always helps admins and other MacLeods if you include a link to your MacLeod family tree. Here are some reference materials that may be of interest: In 2023, we gave a talk entitled 'The DNA of Clan MacLeod' at the Clan MacLeod Parliament on Skye. The YouTube video of this presentation can be found here: https://www.clanmacleod.org/parliament-2023-dna-presentation/ In 2025, we published the main findings of the MacLeod surname project in the Journal of Genetic Genealogy. The abstract from the paper is below. A copy of the paper can be found here: https://www.clanmacleod.org/genealogy/dna-project/dna-of-clan-macleod-paper/ On the Clan MacLeod website (https://www.clanmacleod.org/), under the Genealogy tab, you can also find a ‘Beginner’s guide’ to DNA testing as well as guidance for DNA testing. If your surname is known as a Sept of the MacLeod Clan, we encourage you to join the MacLeod Septs project at FTDNA. See https://www.familytreedna.com/groups/macleodsepts/about From the Journal of Genetic Genealogy, Winter 2025, Vol 13, No 1. The DNA of Clan MacLeod By Mark K. MacLeod, Colin Macleod and Roderick A. F. MacLeod Administrators of the ACMS MacLeod surname project at FTDNA Abstract The powerful MacLeod clan is thought to have originated in the Scottish Highlands in the 13th century. Twenty years ago, MacLeod clan members started Y-DNA testing to learn more about their origins. By analyzing the large dataset that has accumulated over these two decades, we found that most MacLeods in the MacLeod surname project at Family Tree DNA can be placed into one of five genetically distinct subgroups. MacLeods in the largest of these subgroups are proposed as the patrilineal descendants of the founder of the clan. Accordingly, the other four genetic subgroups comprise those whose distant ancestors became part of the clan and assumed the MacLeod surname. The SNP BY3210 is common to all MacLeods in our proposed founder subgroup. The subsequent formation of two mutually exclusive descendant SNPs, FTT137 and FTT138, coincides with the traditionally established split of the chiefly line into two main groups: the Harris & Dunvegan and Lewis & Raasay branches. Several MacLeods with documented genealogies leading to these two chiefly lines carry SNPs consistent with this split. On a speculative basis, we have linked several other SNPs to early MacLeods in the chiefly lines. While there are some noted discrepancies, the estimated age of these SNPs fits with the history of Clan MacLeod. Autosomal DNA results show that MacLeods crossmatch other MacLeods in all five Y-DNA genetic subgroups. This suggests that MacLeods who descended from the founder intermarried with MacLeods whose ancestors assumed the surname. Therefore, most MacLeods in the world today will have a link back to the founder – either along their paternal line or through a maternal connection in other parts of their family tree. Four of the five genetic subgroups have origins in different parts of Scandinavia while the fifth subgroup has Celtic origins. The DNA evidence shows that the MacLeod clan was a melting pot of these diverse groups. Finally, Y-DNA evidence shows that the founder branch was likely in the Earldom of Orkney before arriving in Scotland. These Orcadian ancestors originated in Norway, consistent with the traditions of the clan.