Ancestry DNA ThruLines: What Does It Do?

If you've been bombarded with news of AncestryDNA's new feature, ThruLines™, you may be wondering what it is and what it can do for you.

I woke up Friday morning to an email from a research cousin to one of my DNA clients asking and exclaiming all sorts of things about ThruLines™. Basically, she thought the magic of technology was finally happening for her DNA results.

So is ThruLines™ like the magic results so many people assume DNA will give? Is it the opposite, a lot of hype that will mislead you? I think it's somewhere in-between, a great time saver when used correctly.


Before I get going, this is a brand new feature and I didn't get any advanced peek at it or any special information from Ancestry.com regarding it. I'm just like you, I saw 6 million ads that Ancestry had big announcements to make at RootTech and then I got access to ThruLines™.

That means I don't have all the answers. The point of this post is more to provide the same response I gave the research cousin.

How I may be unlike you, I spend hours every day doing genetic genealogy. And it's not all for my own family so I get a "bird's eye view" of some of these tools a little quicker because I have a lot more to compare to.

So let's get started!

First, ThruLines™ isn't something totally new. It is a variation on the "DNA Circles" that have been provided for a while. I do think it's a much more user-friendly version of Circles BUT that also means you are more likely to misunderstand or misuse it because it seems so straight forward.

I can give you all the basics about ThruLines™ but lots of bloggers will do that so I'll point you towards them for some background, if you need it. The DNA Geek has written a nice post about ThruLines™ with images and basic info, AncestryDNA’s ThruLines™.

Here are the big issues you need to realize to be successful getting started with ThruLines™.

You will get your tree based relationship AND amount of shared DNA.

• Don't get confused and think you're getting a DNA based relationship just because the shared DNA is displayed.
• Don't be thrown off if the computer "misreads" your tree.

The first is an easy point of confusion. The second is more important in some ways.

It happens the research cousin that emailed me Friday morning (ThruLines™ was announced on Thursday) had a misread error with her tree. For some reason, the Ancestry algorithms didn't recognize the husband of the couple we are working on. It created a ThruLines™ for the wife and their descendants.

Why is this important?

All the tree based relationships were shown as "half-..." which is a different amount of estimated shared DNA. Since this was a new tool, she (very understandably) thought there was some DNA significance indicating the half relationships. She had combined the two points I made above, thinking the relationship was DNA based and not realizing the computer had "misread" the tree.

I have no idea why the husband was not picked up in the comparison. There are a lot of things I don't understand yet about ThruLines™ automated tree reading. These may get worked out over time or we might start to figure out the tweaks we need to make to our trees to fix them ourselves.

Next, big issue #2.

Your tree no longer needs to "match" the trees of your DNA matches, perfectly.

This is a really exciting improvement but also a point you need to be careful with.

• ThruLines™ will "complete" the lineage to a shared ancestor even if both trees do not show that lineage.
• ThruLines™ will complete a lineage, without consulting a human about it.

This is the same issue, you just need to think of it as both a positive and a negative. I spent Friday looking at ThruLines™ for a client's tree, not my own tree which I'm much more familiar with. That means I felt the awesome time-saving power of having those lineages completed for me, especially with a common surname like Taylor.

I can't tell you how much time I've spent completing the trees of matches to find the known ancestor we share.

Didn't you take a DNA test to find the UNknown ancestors?

But you have to work with the known first. Doing this as fast as possible is ideal and ThruLines™ makes fast, faster.

On the opposite side, this is still a technology based on the trees uploaded by Ancestry.com users. They are prone to massive problems. They WILL perpetuate the same lineage errors over and over again.

There is a solution.

Use your brain!

Look out for errors, especially errors you know have been passed around online trees.

If you don't know how dangerous it is to rely on online trees, learn.
RELATED POST: Evaluating Evidence: Books (not about online trees but a good starting place)

With that being said, I couldn't do genetic genealogy (especially professionally) without using online public trees. I know there are times I'm having problems because I'm using lots of online trees. You need to develop the skills to recognize how much you can rely on online trees. With DNA, you have to rely on them some. I rely on them far less with traditional research.

With DNA, sometimes it doesn't matter if the lineage is wrong, as long as it leads to the right place. This has to do with the fact you have to deal with the known before learning about the unknown.

When you're working with matches with a known relationship to you, that is laying the groundwork so you can work with unknown relationships. As far as strict DNA analysis, the analysis of the numbers, not the actual trees, it doesn't matter the names, dates, or places as long as the relationships are right.

I consider working with online trees a step in the process. Just like I'd do a literature review with traditional research (finding all the published sources easily accessible), I use online trees, first. Later I'll get into my own research just as I'd go beyond published sources.

ThruLines™ is a great time-saver to work with known relationships. Just keep an eye out for potential problems.

Perhaps the biggest ThruLines™ issue to be aware of.

How Do You Get ThruLines™?

If you don't have ThruLines™, you've got a little statement in the ThruLines™ box telling you what you have to do. I'll tell you it isn't a black and white answer.

• Simply attaching a searchable tree of three to four generations won't automatically get you ThruLines™. There's something more going on.

My test does not have ThruLines™. My mother's does. My paternal great-aunt's does. It's the same tree! I had DNA Circles but I don't have ThruLines™.

Attached tree but no ThruLines™

Most annoying of all, the client project I was working on on Friday, she doesn't have ThruLines™, I was using the tests of the research cousin. I have some suspected known ancestors of my client I'd like to confirm (I've tried emailing the matches and hit a wall of silence, and refusal, in one case).

So I can't answer the question of how to get ThruLines™.

There's more to it than a (public or private) searchable tree of a certain depth. I'm sure the computer has to have enough collateral lines to match to those incomplete lineages of your matches. That's something I've always suggested people skip if they have issues attaching a tree (i.e. just load your direct lines because it's easier to type those from scratch if that's your only option).

If you want to use ThruLines™, there's obviously value in adding branches to the tree attached to your DNA test. I personally recommend you learn to download your tree to a software program that will allow you to add branches. I call this slicing and dicing my trees, to give you a more visual idea of what I'm doing.

You can do this in FamilyTreeMaker, Legacy Family Tree, or RootsMagic just to name a few.

You can of course just use the tree attached to your DNA results as your primary tree but I recommend against this in general because you sometimes want to treat the DNA tree differently to use tools (like ThruLines™) or test a hypothesis.

Learning to use a software program (even if it's just a free version to download and upload GEDCOMs) is a skill any emerging genetic genealogist should master.

What can you expect from Ancestry's ThruLines™?

So let's recap the issues I've identified in these early days of AncestryDNA's ThruLines™.

• The relationship given is tree based, not DNA based.
• The relationship is based on how the computer sees your tree, it might not recognize someone giving you a half-relationship (or no relationship or even false relationships).
• ThruLines™ can save you time by auto-completing lineages of your matches, no exact tree match needed.
• ThruLines™ can mislead you by auto-completing lineages of your matches. No human was involved.
• Getting ThruLines™ to show up isn't as simple as attaching a tree of three-four generations.
• Adding collateral lines to your DNA tree can help if you want to use ThruLines™.

If you're looking for an even more in-depth rundown of ThruLines, check out this post with warnings about using ThruLines, from DNAeXplained.

So what have you thought of ThruLines™? Have you made miraculous discoveries? Have you run into problems? Leave a comment.