Genetic Genealogy and Non-Paternal Events

There is a certain occurrence in genetic genealogy called a Non-Paternal or Non Paternity Event. This is a break in the ancestry of a person’s Y chromosome and surname. A person named “Smith,” for instance, might have a Y chromosome that is clearly “Johnson.”

A non paternal event can occur when an adopted male takes the surname of his adoptive family, or a male child takes his step-father’s surname, or a male child takes his mother’s surname (undoubtedly there are other circumstances as well).

When a break in the Y chromosome is suspected or confirmed, it is possible that the break might have occurred 1,000 years ago, 100 years ago, or with the testee’s birth.

An article in The Atlantic titled “Who’s Your Daddy” addresses the ‘unintended consequences of genetic screening for disease.’ Or, in some cases, the unintended consequences of testing for genetic genealogy. The author, Steve Olson, recently underwent genetic genealogy testing:

“A scientific officer at a genetic testing company knew that I was interested in genealogy, and he had offered to run my DNA through a sequencer. A few weeks earlier, I’d swished mouthwash inside my cheeks, sealed the mouthwash in a tube, and mailed the tube to the company.”

The results of Mr. Olson’s (when I say that name out loud, all I can think of is ‘Little House on the Prairie’!) test revealed that his DNA was what he predicted it would be – of Scandinavian descent.

However, as Mr. Olson points out, this doesn’t always happen. The article cites Bennett Greenspan, of Family Tree DNA, as stating that “any project that has more than 20 or 30 people in it is likely to have an oops in it.” This aligns well with the traditional belief that anywhere from 5 to 15% of men are not the actual biological fathers of their children. Following this out 10 generations, there is a 40% chance of a non-paternal event!

Along the same lines, a recent article was published on the Wall Street Journals ‘informedreader’ blog titled “As DNA Tests Spread, So Do Nasty Paternity Surprises.” The article cited Steve Olson’s piece in The Atlantic.

I must admit, I have a deep understanding of this issue and the effect it can have on tested individuals. I have a solid paper trail to Germany back to the 1750’s, but when I received the results of my test, I was shocked to find that my DNA belonged to a small and unique subclade of R1b1c that was only found in England! All of my closest matches also originated in the British Isles.

My first thought was a non-paternal event. I even asked my Mom whether my dad was actually my dad (I was 99.9% joking, of course)! I was so proud of my German heritage, and here I was faced with the possibility that I wasn’t German at all.

However, after a few months, new results showed that other people belonging to the unique subclade of R1b1c also originated in the same area of Germany that my ancestors came from. Thus, rather than worrying about a potential non-paternal event, I was the first person identified with this subclade to be from Germany.

Thanks to Hsien at EyeonDNA for her help!