By: Katy Rowe-Schurwanz

Each Big Y test comes with a lifetime analysis of your results. Explore what the process looks like internally and events could lead to a new haplogroup.

Over the past few years, some in the wider genetic genealogy community have referred to the lifetime analysis process as a “manual review” and have suggested that all Big Y testers will receive this within a couple of weeks after their results are complete.

This term has become entrenched in Big Y terminology, leading new customers to believe that after their initial results are posted, the kit will be examined individually by the Big Y team, and haplogroup changes will be implemented at that time. This is a misconception about the way results are analyzed and has led to frustration when nothing changes on the kit for weeks, months, or even years.

The Big Y team does a review of the aggregate data, not each individual kit. With hundreds of kits in a batch, it would be logistically impossible to review each one. However, the Big Y program compares each batch of incoming data against the entire database of existing Big Y testers. Then, a proprietary in-house tool flags locations where changes could be warranted, and those are reviewed and updated.

If the incoming kit does not trigger that flag, it typically means the data does not contain any private variants that match up with existing testers to be added to the tree or form new branches. This process is repeated with every new upload of Big Y data.

Let’s take a closer look at what that means over the lifetime of Big Y results.

What is Big Y Lifetime Analysis?

Lifetime Analysis refers to the Y-DNA haplotree continuing to grow and evolve over time. The Big Y test sequences millions of Y-SNPs on the Y chromosome and finds new Y-SNPs that have not yet been named and placed on the Y-DNA haplotree; these Y-SNPs are called private variants.

Your Big Y SNP results are compared to everyone else’s Big Y SNP results to not just find matches but to expand the Y-DNA haplotree.

Identifying Private Variants and Equivalent Y-SNPs for Further Y-DNA Haplogroup Refinement

Naming Private Variants Shared with Other Testers

The Big Y is an exploratory test that looks for new Y-SNPs on the Y chromosome. When these new Y-SNPs are discovered, they’ll be placed in your “Private Variants” section under your Results and will be listed by the position number where they fall on the Y chromosome.

Big Y shows you private variants within your Y-DNA that may be named eventually with lifetime analysis

Our phylogenetic expert will also check to see if these new Y-SNPs have been discovered by another lab already or not. For the ones that have not, we’ll name those Y-SNPs and submit the names to ISOGG (the International Society of Genetic Genealogy).

Y-SNPs discovered from the Big Y-500 will have the prefix BY followed by a number, e.g., BY147, BY592.

Y-SNPs discovered from the Big Y-700 will have the prefix FT (or FTA, FTB, FTC, FTD, etc.) followed by a number, e.g., FT385, FT62.

The numbers will be assigned in the order in which the Y-SNP was discovered. For example, the first Y-SNP discovered by the Big Y-700 was FT1, the second was FT2, and the 4967th was FT4967.

Your private variants are compared to the private variants of other Big Y testers. If someone else shares a private variant with you, then that variant receives its official name and may be placed on the Y-DNA haplotree. This may form a new branch; and you and that tester may be moved to that branch, and your haplogroup may be updated.

Equivalent Y-SNPs Can Confirm or Split Branches

Many existing branches have “equivalent Y-SNPs” on them, meaning that there are multiple Y-SNPs that appear to belong to the same place on the tree.

Everyone who has tested positive for one of those Y-SNPs has tested positive for all of those Y-SNPs.

Everyone who has tested negative for one of those Y-SNPs has tested negative for all of those Y-SNPs, and the branch is unable to be broken up yet.

Equivalent Y-SNPs indicate a haplotree branch split through Big Y lifetime analysis

When some testers test positive for some of those equivalent Y-SNPs and negative for other equivalent Y-SNPs on the same branch, the branch can be split. Some Y-SNPs will remain on the original branch, and some will be moved to a new branch.

When this happens, you and others may be moved to the new branch, and your haplogroup may change.

Automated Big Y Tools Identify Y-SNPs That Need Names or Split Branches

FamilyTreeDNA has created automated tools for our phylogenetic expert, Michael Sager, that identify when new Big Y results indicate if a branch of equivalents can be split or when private variants can be named and placed on the tree.

As batches of Big Y results are completed in the lab and are posted to accounts, the automated tools start identifying potentially actionable changes to the Y-DNA haplotree. The two primary things that these tools identify are branch splitters and shared private variants.

Branch Splitters

Branch splitters get identified when a sample has negative results on or upstream of their current branch, and these are typically addressed first before the shared private variants. These splits may cause you to be placed on a new branch and may refine the age estimate for your branch.

Sometimes, branch splits happen fairly high up on the Y-DNA haplotree, like one from January 2023 that split Y-DNA haplogroup R-L754, also known as Y-DNA haplogroup R1b1.

Big Y lifetime analysis identified a branch splitter at R-L754 or R1b1

The split is based on the DNA test results of a Tajik man from a 2022 study. His DNA added a new data point in the migration story of millions of men. A majority of men in Europe are descendants of these R1b1 genetic ancestors. Their Y-chromosome signature spread into Europe from Central Asia during the Bronze Age.

The Tajik man is from the Sughd Province in the Republic of Tajikistan. Tajiks are a Persian-speaking Iranian ethnic group native to Central Asia. The new Y-DNA haplotree structure is R-L754 (3 SNPs) > R-L761 (17 SNPs). The split is estimated to have happened around 16,500 BCE.

Shared Private Variants

The automated tools also identify samples that have shared private variants. Larger portions of the Y-DNA haplotree are focused on here and worked through at the same time. So all of the shared private variants in Y-DNA haplogroup I are looked at, then haplogroup G, then J, the R1a, then R1b, etc.

When two or more samples have enough positive reads for the same private variants, those variants may be named and placed on the Y-DNA haplotree, and a new branch might be created. If that happens, some of those samples may find themselves placed on that new branch and may receive a new haplogroup.

If you’re a Group Project Administrator working with Big Y results for your project members or if you’re just comparing your own Big Y results to your matches’ results and you notice that a new result has come in that shares private variants with an existing result, there’s no need to reach out to FamilyTreeDNA. All you need to do is be a little patient. Our automated tools will identify the shared variants, and if there is enough phylogenetic evidence for a change, it’ll happen.

When will your haplogroup change?

If you have taken a Big Y, your haplogroup will change when there is phylogenetic evidence to make a change. There is no standard time after you receive your initial Big Y results when this will happen.

You may have a change soon after your results come in if your results are the ones that cause a branch split or private variants to be named. If that’s the case, you’ll see an update within a couple of weeks of getting your results.

If you’re in an under-tested part of the Y-DNA haplotree, then your Y-DNA haplogroup may not change for weeks, months, or even years after you receive your initial Big Y results. It all depends on how many testers receive results for your part of the Y-DNA haplotree; if there are relatively few or no testers, then you won’t see a change until there are more.

Automated Notifications for Updated Big Y Haplogroups

Some parts of the Y-DNA haplotree are extremely well-tested. If you belong to an extremely well-tested part of the Y-DNA haplotree, then the equivalents may all already be split, and the private variants may all already be named and placed on the tree. This means you’re as refined as you can get when your results come in, and you won’t ever see your Y-DNA haplogroup change.

We will soon release some new email notifications that will inform you when your Y-DNA haplogroup changes or when a Group Project member’s Y-DNA haplogroup changes, so you will always be notified when such a change happens.

The email will include the previous Y-DNA haplogroup and the new Y-DNA haplogroup. Within 24 hours, you’ll be able to sign in and check out the new placement on the Block Tree and the Y-DNA haplotree.

You may need to wait a week or two before you can view the updated Discover™ reports, as those are typically updated every week, whereas the Block Tree and Y-DNA haplotree are updated daily. The Discover platform does not directly connect to the Big Y database like the Block Tree and the Y-DNA haplotree, so changes such as new Y-SNPs, Group Project subgroup changes, and new Group Project Members will not be immediately reflected.

How can you help refine your part of the Y-DNA haplotree so your haplogroup changes?

  • Join relevant Group Projects to find testers who you subgroup with and encourage the ones who don’t have a Big Y-700 to upgrade.
  • Recruit more testers! Look at your Y-STR matches and find those who haven’t yet upgraded to the Big Y-700. Encourage them to upgrade.

You can also recruit patrilineal family members. Testing another immediate family member, like a brother, father, uncle, or first cousin, isn’t likely to help here. The vast majority of the time, their results will be exactly the same as yours. It will cause your private variants to appear as named Y-SNPs instead of by their position, but it may not split them up and create new branches unless the branches closest to you are not really close at all. To fill in your branch, though, we recommend recruiting more distant patrilineal cousins to test—4th cousins, 5th cousins, and so on.

Headshot of Katy Rowe-Schurwanz - Product Manager at FamilyTreeDNA

About the Author

Katy Rowe-Schurwanz

Product Manager at FamilyTreeDNA

Katy Rowe-Schurwanz has always been interested in genealogy, inspired by her maternal grandparents, who told her stories about their family and family history when she was little. After studying anthropology and history in college, she joined FamilyTreeDNA in 2015 and became the Trainer for Customer Support. Katy created and improved training processes and was fundamental in the creation of the Big Y Specialist team. In September 2021, she became Product Manager and has focused closely on improving FamilyTreeDNA’s genetic genealogy products.