What Does It Mean If You Share a Paternal Haplogroup?

Do you share a paternal haplogroup with someone? If you wonder what this means, and if you might be related to this person, this article will answer your questions.

The idea of sharing a haplogroup with someone, especially a DNA match, can be confusing. Admittedly, the concept can be a bit abstract.

So, let’s make it less confusing and clear things up a bit.

What does sharing a paternal haplogroup tell you?

If you share a paternal haplogroup with someone, it means that you and that person share a direct-line paternal ancestor in common somewhere in your family tree. The common ancestor could be as recent as a father, or as far back in time as several thousand years.

In other words, if you could trace your father’s father’s father’s line all the way back into history, and the person who shares your haplogroup did the same, you would eventually meet at the same direct-line paternal ancestor.

Scientists are able to determine your paternal haplogroup by testing your Y-DNA. Y-DNA mutates slowly over time, going through several small changes every several generations.

Over time, these small mutations add up to bigger changes in the Y-chromosome. These big changes sometimes result in the determination that a new haplogroup or subclade, which is a branch of a haplogroup, has formed.

Everyone who is descended from that new haplogroup is a direct-line descendant of the first man born with that new lineage.

How far back is the common ancestor with a shared paternal haplogroup?

The number of generations that you would need to go in order to identify the shared direct-line paternal ancestor between you and someone who has your paternal haplogroup would vary dramatically. If you only have a general Y-DNA haplogroup, which includes a letter, a dash, and another letter and number, your common ancestor could be many thousands of years back in history.

Most people will find that they can’t trace their family tree back more than eight or so generations on most lines of their tree. In my family tree, eight generations takes me back on my dad’s paternal line to 1739 in Groningen, the Netherlands, which is where I get stuck.

My dad’s Y-DNA, or paternal, haplogroup is R-L2. According to 23andMe, that haplogroup is about 8,000 years old, though some sources state it could be only 4,500 years old, which means that my dad is descended from a male child of that man who lived as long ago as 8,000.

Any male who shares the R-L2 haplogroup with my dad is also descended from that ancestor 4,500-8,000 years ago, and could be as closely related as a brother sharing the same father with my father. Alternatively, it could be someone descended from a collateral line – a different son of that ancient ancestor, or any one of his direct-line male descendants.

You can get an idea as to how far back the common ancestor you share with your “Y-DNA match” could be by more closely examining your paternal haplogroup. Some Y-DNA tests provide more in-depth, specific Y-DNA haplogroup and subclade results, such as the Big-Y test available from Family Tree DNA.

These more specific tests are able to identify more recent mutations in the Y-chromosome, and even often Y-DNA matches with genetic distance calculated for each match. The genetic distance information can help estimate in terms of hundreds of years, instead of thousands, how far back one would need to look for a common ancestor.

It’s possible to share a paternal haplogroup and be related in another way

If you have tested your DNA with an autosomal DNA testing company, such as Ancestry or 23andMe, you might have a DNA match on those sites that also shares a paternal haplogroup with you. It is possible to share autosomal DNA with someone, which means you likely share a common ancestor within the genealogical time frame, and also share Y-DNA with them, meaning that you are also descended from a direct-line paternal ancestor from many hundreds, even thousands, of years ago.

This is important to know, especially for those people who have tested with 23andMe, since Y-DNA results show up for males who have tested there.

If you have a DNA match who also shares your paternal haplogroup, it might be tempting to only look for a connection on your father’s side of the family. However, it is just as likely that this person is related to you on your mother’s side of the family, so you should fully consider both options.

You could be related to this person on your mother’s side of the family based on your shared autosomal DNA, and your father’s side of the family through your shared direct-line paternal ancestry going back many generations.

Why close relatives don’t share the same paternal haplogroup

If you were expecting to share a paternal haplogroup with someone, but your DNA results show different Y-DNA origins, there are three possible explanations. The most likely reason is that you shouldn’t share a paternal haplogroup because you have different direct-line paternal ancestors.

For example, my dad has a male first cousin who shows up on his 23andMe results. 23andMe tests a paternal haplogroup, and I can see that my dad and his cousin have a different Y-DNA haplogroup.

It would seem logical for two male close relatives (i.e. first cousins) to share a Y-DNA haplogroup, but in my dad’s case, they don’t. This is because my dad is related to this cousin on his mother’s side of the family.

My dad inherited his Y-DNA from his father, and his cousin got his Y-DNA from his father (his mother’s brother). Since my dad’s father and my dad’s cousin’s father have different direct-line paternal ancestors, their paternal haplogroup does not match.

The less likely explanations for not sharing a paternal haplogroup when you think that you should include that the haplogroup may have changed names over the past decade. You can determine whether your haplogroup has undergone a name change by doing a Google search with the name of your haplogroup and doing a bit of research about whether it was previously known under a different name.

Finally, unexpected Y-DNA haplogroups could reveal a non-paternity event, also known as NPE, in someone’s family tree. Y-DNA is most useful to exclude the possibility of being descended from a direct-line genealogical paternal ancestor.

Do women have paternal haplogroups?

Females do not have paternal haplogroups because they are not born with Y-DNA, which is the DNA that is tested to determine a paternal haplogroup. Only males are born with Y-DNA, which is why this type of DNA testing is only available to males.

However, even though females don’t have paternal haplogroups, they can still trace their paternal lines.

Why do you have paternal haplogroup on your DNA results if you are a woman?

Since females do not have Y-DNA, they can’t show a paternal haplogroup on their DNA results, with one exception.

If you are female and tested with 23andMe, it is possible to connect your DNA results to a male relative who has also tested with 23andMe. If you went through this simple process of connecting your results to your father, uncle, or brother, you may show a paternal haplogroup in your results.

Asking a close male relative to take a DNA test to show patenral haplogroup is a great way for females to learn more about their direct-line male ancestors, and even our DNA matches.

Conclusion

I hope that this post has helped you understand your paternal haplogroup and how you might be related to anyone who shares that haplogroup with you.

If you have any questions about something that you read in this post, or if you would like to share a question or story about exploring your own Y-DNA haplogroup, please join us in the discussion below.

Thanks for reading today.