New haplogroups, which are phylogenetic tree branches, are formed with periodic updates to the Mitotree. In the November 2025 Mitotree release, 12,773 new branches were formed, and an amazing 67,000+ people received a new haplogroup. Haplogroups are relevant for both genealogy and more distant information about your direct matrilineal ancestor and their origins.

Are You a Candidate to Receive a New Haplogroup?

Lots of people have asked how one might know if they are a candidate to receive a new haplogroup, or tree branch, or why they didn’t, so let’s talk about the three ways your haplogroup could potentially change.

To follow along, if you have taken the full sequence mitochondrial DNA test, sign in to your FamilyTreeDNA account and click on Discover on the mtDNA Results and Tools page.

After clicking on Discover, you’ll see the mtDNA Discover sidebar menu on the left. Click on Scientific Details

You Have Private Variants

The first reason you might be a candidate to receive a new haplogroup is that you have private variants. Private variants are mutations that have not already been used to form a haplogroup, hence, they are still private to you.

To see if you have private variants, click on Scientific Details on the sidebar, then on the Variants Tab.

You’ll see a list of haplogroups under the Placement column header. Your assigned haplogroup is noted by the red square, J1c2f in this instance.

At the top is an “F” number, which is your Haplotype. Haplotype numbers are randomly assigned, and everyone with exactly the same mitochondrial sequence will have the same haplotype number.

You can see your haplogroup and haplotype matches on your match list. If you match both, both blue circles will be checked.

In this example, you can see that beside the haplotype number, which I’ve blurred, in the Name column, it says “No private variants.” This means that all of this person’s mutations have been used to assign them to haplogroup J1c2f and the haplogroups upstream of J1c2f.

This tester cannot match anyone any more closely than the exact same haplogroup, J1c2f, and the exact same Haplotype number, which means they match exactly and have no private variants. This means there’s no material available to form a new haplogroup.

I’ve written about mitochondrial haplogroups, haplotypes and haplotype clusters, in two articles.

• Mitochondrial DNA: What is a Haplotype Cluster and How Do I Find and Use Mine?
• Cheat Sheet” Mitochondrial Matches, Haplotype Clusters, and Haplogroups

Let’s look at an example of someone who does have Private Variants.

This tester, who is a member of haplogroup C4c1h has one private variant, T13879g. When another tester in haplogroup C3c1h also has this variant, or mutation, they are candidates to form a new branch in the next Mitotree release.

Keep in mind that not every private variant will become a haplogroup, based on several scientific factors.

So, while our haplogroup J1c2f tester is NOT a candidate to form a new haplogroup branch due to no private variants, our C4c1h person with one high-quality private variant is.

However, private variants are only one way in which a new haplogroup might form. There are others.

The Tree Splits Upstream

Sometimes the tree splits upstream.

Looking further upstream, or back in time from haplogroup J1c2f, we see that two of the foundation haplogroups that formed J1c2f are defined by more than one mutation.

Haplogroup J1 was formed using both C462T and G3010A, bracketed in red.

Haplogroup J was formed using seven different mutations, beginning with C295T and continuing to the bottom of the screen capture, bracketed in purple.

As more people test, eventually a new tester may have C462T, but NOT G3010A, AND their downstream mutations are different too. In other words, we’re not looking at a reversal for 3010, but at a completely different haplogroup with a split at C462T as its defining mutation.

In this case, the new branch would receive the new haplogroup name, and the existing branch would remain the same. But what if this scenario happened far up the tree and changed our understanding of this portion of the tree?

In that case it’s still very unlikely that your haplogroup would change, based on existing naming structures. FamilyTreeDNA makes every effort to NOT rename existing haplogroups when these types of branching situations occur.

The Branch is Renamed

Sometimes the existing tree structure is clarified, prompting branch renaming.

Let’s look at an earlier structure of this portion of haplogroup J1c2f.

In the earlier version of the Mitotree, shown above, you can see that two mutations define haplogroup J1c2, two mutations define J1c, and there’s a haplogroup called J1c’g that is constructed using a reversal at location 152.

In the November 2025 release of the Mitotree, this exact same portion of the tree looks different. The tester is still haplogroup J1c2f, but the upstream structure has changed.

• J1c2 is now defined by only one mutation, A188G.
• A new haplogroup has been formed: J1c2+16519. Notice the Weight column at far right. This mutation’s confidence weighting is very low, so this haplogroup is a good candidate for refinement in future trees.

Now look at J1c where we see the same thing occurring.

• J1c is now comprised of just T14798C.
• A new haplogroup, J1c+185 has formed. It has a weight of 17, still in the red zone, but more confident than J1c2+16519.

Looking further down the original placement table, we see J1c’g, which is a collapsed haplogroup based on a double reversal at C152T!!. It’s gone in the most current version of the tree. You can see that haplogroup J1c’g only had a weight of 1, so it was a good candidate to be refined, eliminated, or assigned elsewhere in the tree.

None of these changes affect haplogroup J1c2f itself, meaning the tester’s assigned haplogroup. Unless they actually look at their haplogroup mutations, they won’t see any difference. This person was and still is assigned to J1c2f.

However, if someone was assigned to J1 or J1c2 before, they might have a new haplogroup name. If they were assigned to J1c’g, they definitely have a new haplogroup name.

These scenarios are repeated throughout the tree, and may be exactly why you receive a new haplogroup, even without having any private variants.

Older Versus Newer

Haplogroups that form as a result of your private variants tend to be newer, or closer in time, but not always. You never know when just the right person will test to split an upstream branch!

Regardless, all new haplogroups help refine the tree, and all refinements are important. Branches that form in more recent generations are often the most useful for genealogy.

However, that’s not always the case. “Newer” versus “older” is sometimes relative (pardon the pun.) Let’s say that you are trying to figure out which of two sisters, or cousins, born in the 1600s, you descend from.

You may desperately need an “older” haplogroup that will divide the branches of the ancestral tree.

Or maybe you want to know whether your ancestor came from Scotland or Germany, so you may need an older haplogroup yet.

Want to know if they were Celtic or from a different culture? An older haplogroup fills in cultural and genealogical blanks that no other type of testing can reach. Haplogroups pierce the veil of time.

OK, So What Should I Check?

Even if you don’t receive a new haplogroup when a new Mitotree version is released, you’re certainly not out of luck.

Some of your matches may have received a new haplogroup, further refining the genetic tree, causing them to cluster together. This should correlate with the genealogical tree.

For example, I’m desperate to identify the wife of my ancestor, who has been known affectionately for years as H2a1. She is now haplogroup H2a1ay1, but I still don’t know her name.

The haplogroup formation date range extends back to around 1820, which is slightly late, but certainly not far off either. The dates for the genetic Time Tree, and the genealogical tree may not align exactly, but the date ranges generally do. Mutations don’t occur on an exact schedule.

However, matches for the tester who represents H2a1 (now H2a1ay1) have been nicely narrowed down to two other full sequence testers. Both have this exact same haplogroup, and one of them also has the exact same haplotype. The balance of her matches are now in a more distant haplogroup.

Now I can focus on the two matches with the same haplogroup.

Even though the trees of these three testers don’t seem to intersect, some genealogical sleuthing tells me a lot.

The ancestor of one of the haplogroup matches was born in 1741, a Quaker, in Chester, Pennsylvania, and died in 1818.

The ancestor of the haplogroup plus haplotype match lived in the same Virginia County as my ancestor, and they were both Quakers, whose families attended the same church.

So we have:

• Haplogroup match – Born a Quaker in 1741 in Chester, PA.
• Haplogroup AND haplotype match – Lived in Frederick Co., VA in the 1780s and attended same Quaker church as the tester’s ancestor

These new haplogroups, both of the tester’s haplogroup matches, and others whose new haplogroup shows they are more distant, are critical to refining my search.

I’m so close to identifying H2a1ay1 and her parents that I can smell it!

Any self-respecting genealogist would end this article right here and get busy!

I’m outta here!!!

Don’t stop with checking your own haplogroup. Review any changes to people on your match list and view the Match Time Tree, even if you didn’t receive a new haplogroup.

While receiving a new haplogroup is exciting, sometimes refinements among people around you can be equally, if not more, important and informative.

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