Wednesday, 29 December 2010

A 37 Marker DNA

I have said on more than one occasion that I have chosen to have my DNA analysed (by in the hope that other male McIlhagga's might follow suit and so possibly establish a recognised DNA pattern for our clan. Of course there is always the possibility that a particular ancestral line (including my own) might have become 'corrupted' by someone in the paper trail who had or has the surname but who has or had been fathered by a man who had a different genetic make-up, and probably a different surname. This chance has to be recognised though of course in one sense the possibility adds to the general interest. The opposite may of course also be true. The McIlhagga genes may have found their way into an ancestral line which has a surname which doesn't appear to be related in any way to our clan. To put it plainly, there may be an illegitimate birth somewhere in the line, an event which is extremely common in many families.

Since I had my DNA analysed four years ago no other male McIlhagga (or other clan surname) has sent their DNA for analysis - until this last couple of months! An analysis is returned with a code on either 12 markers, 25 markers, 37 markers or 67 markers. The advice is that 37 markers are sufficient to establish a very good match, though it is clearly of interest if a lesser number of markers match. The agency that does the analysis lets me know when a 'match' occurs, at any of the levels. In the past four years while I have been waiting and hoping that another known clan member might have his DNA analysed I have been informed of 1068 12-marker matches and 123 12-marker (genetic distance - 1) matches. I presume these are 11 marker matches, or perhaps 13. I have been notified of one 25 marker exact match, that of a Mr. Smith in America. Yes, I know I have here broken my rule of not referring in this blog to someone who is alive, but I do this on the assumption that it would be impossible to identify someone with one of the commonest names in the world! I have corresponded with Mr. Smith and exchanged photographs, in the hope that we might spot a family likeness. I'm afraid I am not sure that we have. I also have the names of two people with 25-marker (genetic distance - 1) matches and 11 names of people with 25 marker (genetic distance -2) matches. I presume these people have respectively 24 and 23 marker matches with my DNA. I do not think that any of these 13 surnames indicate a clan link to McIlhagga.

However, now we have a second McIlhagga whose DNA has been analysed. He happens to be my third cousin once removed. The 'once removed' means that we are a generation apart. The 'third cousin' means that we have a common ancestor who is my GG grandfather and my cousin's GGG grandfather. That person was someone about whom I have written in earlier blogs, namely William McIlhagga of Ballycloghan, County Antrim, who married Agnes McCosh of Clogh, County Antrim. My cousin is descended from their first son and eldest child, William. I am descended from their third son, Crawford. After my cousin sent his DNA sample for analysis first published a 12 marker result, and we were identical! But as we know not much can be deduced from 12 markers. I waited anxiously for the next couple of weeks until the 25 marker result came through. It showed that we were identical!! And then finally this last week the 37 marker result came through on 23rd December. We are identical!!! It was my best Christmas present. Perhaps we now have a DNA analysis against which we can reasonably compare any future analyses which might be done. Thank you, third cousin, once removed.

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