NPE - "Non-Paternal Event" - If you are involved in the use of DNA to further your genealogy research, you are most likely aware of the term "NPE" - the most common term for describing the different possibilities for why your surname is different from the other men you match. Another term that is more descriptive, but too complicated for common use is "Surname Discontinuity Event". I'm sure there are other terms used in polite company - and a few folks may snicker and use some non flattering term - which really isn't fair - because it assumes the worst case - which may not be correct.
There are a number of possibilities why your surname can be different from the men you match. Here are the most common ones:
- Unrecorded adoption - many times during periods of hardship (such as living on the frontier) a family could no longer raise their child. If a man raised his sister's child, he would often give him his surname - which would be different from the child's father's name - and the fact may have been lost in the mists of time.
- Unrecorded affair - the first thing folks think of - but it isn't the only possiblity
- Intentional (but unrecorded) name change - which could have occurred for legitimate reasons (such as when a man married a woman who was from a titled or landed family, and she had no brothers, so her husband became holder of the title and usually changed his name) - or it could have been done to aid a person in leaving a past life or even because a man just liked the name.
- Late adoption of surnames - a situation that is fairly common for those coming from "eastern" europe - particularly those of Jewish descent. I still remember my astonishment the first time I dicovered a man with over 50 matches at 37 markers - with over 40 different surnames among his matches. After digging, I found the explanation - which made a lot of sense - as most of his matches were either "Jewish" sounding - or appeared to be "eastern european"
- The last reason that comes to mind is the flawed paper trail - which we have found several times - both where a Barton man matched Lineage I where we didn't expect it and where he didn't match Barton Lineage I when we expected he would. In both situations, we have an example of having the yDNA result cause a re-examination and then revision of the paper trail. I immediately think of three examples - but would probably recognise more if I systematically reviewed every paper trail in the Barton project.
As an example of how prevalent the various forms of NPE are - here are the known surnames that are matching our Barton Lineage I genetic group of almost 100 men:
These 14 men make up just over 14% of our Barton Lineage I. If memory serves correctly, 5 knew in advance that their paternal ancestry was Barton, one was adopted and did not know he his father was a Barton, at least two knew of a suspected affair (one of them knew it was with a Barton), and the other 7 (half) were surprised to be matching Barton. We've also had several men with other surnames test in our Barton project because they believed they would have Barton Lineage I yDNA - and then didn't. And - we've had a handful of Barton men we were "sure" would be Barton Lineage I - who turned out to have some other genetic profile - apparently having their own NPE somewhere in their past.
Have fun with your own search - but don't be embarrassed if you match men with another surname - as there are many reasons and you probably won't know which led to your situation unless you are both diligent and lucky in your search.