Corson & Carson (& other variants) have been linked to Dumfriesshire, Scotland. See www.electricscotland.com/history/dumfries/history20.htm& several other references, linking these surnames to the 13th Century Italian Corsini. My wife is a Carson, from the line Carson of Ballybay, County Monaghan, Ireland. Recently, a brother of hers had 37 STR yDNA markers tested, & this predicted Haplotype J2. Currently, there is no other J2 to be found at www.worldfamilies.net/surnames/carson/resultsHowever, I note that both Corson www.corsondna.com& Coursey/Courson www.worldfamilies.net/surnames/coursey/resultsdo have some J2 samples. Although these samples do not match the STR markers of my Carson brother-in-law, knowledge of membership in the same haplogroup of these seemingly unrelated lines may ultimately be of some help in understanding the larger picture.
J2 in the British Isles is not Viking, not Celtic, but something else (e.g. Mediterranean). Ballybay-Carson J2 may have arrived in Scotland in Neolithic, Roman, or other time frame. Stephen Oppenheimer, in “The Origins of the British”, indicated that in Neolithic times J2 (never a prevalent British Isles type) migrated into Britain & became scattered through southern England, & focal areas of Scotland, but was not seen in Ireland, nor Wales. He states (pg. 238) “…J2 is represented in Scotland with a highest frequency of 7.3% in the old Pictish town of Pitlochry”, which incidentally is located a bit southeast of some traditional lands of Clan MacPherson. This could mean nothing, but I find it interesting. J2 has also been observed to be more prevalent in areas of known Roman occupation, & Dumfriesshire is not so far from Hadrian’s Wall. See www.kerchner.com/haplogroups-ydna.htm and http://freepages.genealogy.rootsweb.ancestry.com/~gallgaedhil/haplo_r1b_ht35_analysis.htm#ht35_fourhttp://freepages.genealogy.rootsweb.ancestry.com/~gallgaedhil/haplo_r1b_ht35_analysis.htm#ht35_four