The "New" Cousin and The lesson Learned Yet Again

Most of those who did DNA testing for my family project did so with Family Tree DNA. I have also tested with Ancestry and 23 & Me and have my kit on MyHeritage. Last week, I found a match on Ancestry with 183 cM of shared DNA over ten segments. 

 

This size match - if it is all from one ancestor - is on the edge of second cousin territory. But of course, we could be more distantly related, in multiple ways.

I wrote to the match (his name is Chris) and it turns out his father in unknown. He uploaded to GEDmatch, where I could see how he lines up with the rest of my families and perhaps get a handle on who might be his father.

Our one-to-one match looked good, but it still didn't tell me if this is all from one ancestor, or more properly, one ancestral couple. 

Once I could see his results on GEDmatch, it became crystal clear. He matches one of my father's paternal first cousins with 1764 cM, with a longest segment of nearly 150 cM. A grandson of this cousin and with no X, he belongs to one of his sons.

This first cousin of my father is deceased as are his two sons. One of those has two sons and the other was never married and had no children.

I made some introductions and they are now talking to each other. I have also given Chris some of the general Pikholz-Kwoczka family background. It remains to be seen if one of my second cousin's sons will test and confirm that Chris is their half brother, or if they will leave it to be determined.

I have three or four Non-Paternal Events in my family genealogy, but never anything quite like this. For some genealogists, this kind of discovery is fairly routine, but not with us.

But I am writing this for another reason. A drum I have beaten here multiple times over the years.

My parents' six unique children all tested. My brother and I match Chris with 179 cM and 155 cM. My sisters match Chris with 260 cM, 214 cM, 169 cM and 116 cM. That is quite a spread for six full siblings.

Two of my first cousins match Chris with 145 cM and 81 cM. All eight of us are related to Chris in exactly the same way, through our grandfather. If my match had been 81 cM, rather than 179 cM, I would have been less interested.

The other second cousins of Chris' father - the same relationship as our own - from one great-uncle 106 cM, from one great-aunt 81 cM. From another great-uncle, brothers whose matches with Chris are 114 cM and 75 cM. From another great-aunt 182 cM, 147 cM and 102 cM.

There is a lot of randomness in DNA matches. Cousins match differently The more cousins you test, the better your chances of finding good matches.