About the MacArthur family
It has long been asserted that the MacArthurs were a branch of Clan Campbell, possibly even the senior line of that Clan, but there is no evidence to support this claim, particularly in terms of genetic genealogy research, which shows that they certainly have no male line descent from the Campbells. The confusion probably arose with the Campbells of Strachur, sometimes known as MacArthur Campbells, who were a branch of the Campbells of Lochawe. Their progenitor was Arthur Campbell (d ca1331), a cousin of Colin Campbell (d 1296) who is commonly known as Cailean Mor, and is the ancestor of the Dukes of Argyll. There is a further cause for confusion between the MacArthurs and the MacArthur Campbells, since there was also a branch of the MacArthurs resident in Strachur in the 18th century.
So far, Y-DNA test results suggest that there are probably at least five distinct MacArthur families, consisting of the major chiefly McArthurs of Loch Awe, with possible branches in Lochaber and Strachur, families from Mull and Skye, and separate families from around Loch Tay and from Islay. The first three groups are likely to carry R-P312, from the major R1b haplogroup and those from Loch Tay and Islay to carry R-CTS4179, from the major haplogroup R1a. R1b is the most common genetic grouping in Western Europe, while R1a in most cases indicates Norse ancestry for those families with Highland origins.
An important aim of the genetic genealogy research on the MacArthurs is to identify the DNA profile of these distinct groups. To achieve this, it will be important that more male-line MacArthurs to take a Y-DNA test and that more of these tests are upgraded to the Big Y-700 test.