There has long been speculation and rumors that some Jam?sons might be descended from Scottish Royalty, perhaps even Kings. The thinking on this is along two separate, although possibly connected theories.
The first theory is based on the fact that some Jam?son families are included as a Sept of the Clan Stewart/Stuart. This is generally considered the Royal Clan and as such the Jam?sons connected with this clan may they themselves be descended from Stewarts with Royal blood. So far, we know of no specific connections to prove this.
The other theory has to do with how the surname Jam?son originally came about. That is, when surnames were first used, many were patronymic, as in son of James became Jameson, or son of John became Johnson, etc. These were common and spontaneous, appearing all over the world and with mostly totally unconnected people. Where the Royal connection comes in, is as a possible relationship to various King James' from King James the first all on down through subsequent and numerous King James', usually with respect to illegitimate children, so as to obfuscate the connection. Although rarely considered, this could have just as likely have been the case with any other member of any one of the Royal families, named James, but not necessarily a King.
No actual proof of this has been substantiated. However YDNA testing can easily confirm or deny any claim of this, at least in a general way. YDNA profiles are known for the Scottish (and other) Royalty, from testing of their known (living) descendants. If any other Jam?son matches that profile, he can make the claim that he might be a descendant. The difficulty with any such claim is that an awful lot of people are in some way descendants, we're talking centuries, and determining exactly how that connection is made can require extensive research, both scientifically (DNA testing) and more traditional (documents). Nevertheless, a very general test can determine you are NOT related, or that you MIGHT be related.
Y-DNA Connections - All of the Kings of Scotland are known to be, at the very least, of the "R" Haplogroups. The "R" Haplogroup, however, is huge, one of the biggest Haplogroups in all of Europe, being part of that Haplogroup in no way suggests you are descendant of any Scottish King, or for that matter any of their extended genetic families. However if you are not a member of the "R" Haplogroup, you are simply not possibly a descendant of a any of the well known Scottish Kings, starting with James I (1394-1497). From there (haplogroup R) the field narrows in relationship to various telltale DNA markers, where one must test positive for #'s M207, P25, M269 and particularly L745. The exact markers are known, and explained in various sites established for just this sort of thing. There are quite a few Jam?sons who are at least at the minimum levels and if tested further might actually find they are genetically at least, descendants of one or more of the Scottish Kings.
The good news is that anyone doing a minimum 37 marker Y-DNA test you can determine if they themselves are in the general category necessary to have any chance of being such a descendant. Beyond that, one may need to test for specific SNP in order to see if there is any closer relationship. To find out more, or to join the Jamieson Family YDNA Project and order a Y-DNA test - we recommend the Y-DNA37 test - please go here.
Jam?son Y-DNA test, associated with Royal families, #: None Known