While on the subject of DNA, was watching a video I had recorded some little while back off of TLC about Vikings, and in the course of the show they were trying to figure out how wide spread the descendants of the Norse were in Britain, and a DNA project done in Scotland had shown that in Orkney, Shetland & the far north Scottish mainland that 60% of the male population had Viking DNA.

So if your ancestors are from these regions you maynot be as Celt as you think but maybe a son of Odin

As an aside, there is a rare genetic hand disease that appears amongst people either from Ireland /Scotland (well, Britain as a whole really), or those descended from them called Dupuytren's Contracture, which is a fixed flexion contracture of the hand where the fingers bend towards the palm and cannot be fully extended (straightened). Amongst those who have had this condition were Ronald Reagan & Margaret Thatcher. The thought is this was passed into the population by the Viking/Norse settlers.