New DNA Tool – DNA Painter Coverage Estimator

Could this new tool help me solve a mystery?

Whenever there are new tools for your DNA, it’s a good day. So October 17th was a good day. That’s the day Jonny Perl from DNA Painter launched his latest product, “Coverage Estimator.”

What does the “Coverage Estimator” do, you ask? Here’s an example of how I can use it. We each get 50% of our DNA from dad and 50% from mom, and we don’t get the same 50% as our siblings. I’ve tested many of my family members, and more of my cousins and second cousins and others have tested. So I might wonder how much of my great-grandfather’s DNA I have access to.

This is something that Paul Woodbury wrote about in his blog post called “Covering Your Bases: Introduction to Autosomal DNA Coverage.” If you read his article, you soon realize doing the calculations would make your brain hurt. Well, it would, mine at least.

Paul Woodbury decided to take this problem to Johnny Perl from DNA Painter, and Johnny created the “Coverage Estimator.” He had help with the calculation from Paul Woodbury and Leah Larkin, but Johnny did the magic. So now you know a bit of the history. You can read more in Johnny’s blog post HERE.

As soon as I read about this, I had to try it. There are two ways that you can create your chart, you can upload a GEDcom, that’s what I did, or you can manually create the chart.

Getting a GEDcom file from your genealogy program (whether it’s online or on your computer) is relatively easy. On your computer, the likely path is to go to the File tab in your genealogy program, and you’ll likely find the download button there.

If your tree is online on Ancestry, you log in to your tree and then go to settings and download the file.

I did search for a way to download a GEDcom file from MyHeritage but wasn’t able to find the instruction. There were a lot of instructions on how to upload to MyHeritage but not the other way around. So if you know, let me know. I did wonder if I could use their Family Tree Builder that syncs with your MyHeritage tree and download it from Tree Builder. But I didn’t try that.

Once you have your Gedcom file, you log in to DNA Painter and go to the Coverage Estimator, and then on the right side, you see “load”

The little box opens, and you import your file from wherever your GEDcom is stored. Usually, that is the download folder unless you have put it somewhere else.

Note just below the Import button, there is also the ability to bring a What Are The Odds (WATO) chart that you might have been working on. This means you need to download the WATO text file and then import it into the Coverage Estimator.

So back to importing our GEDcom file. Once it’s loaded, you will be prompted to say who in the tree you want the coverage chart to be for. So let’s say, in my case, I wanted my great-grandfather, Francis Johnson Middlebrough. After choosing him, there is also a spot where you tick off if you want to anonymize the living people in the tree (which I did), but you can choose to leave all the names. In less than a second, the tree was there. It’s tiny writing below, but it’s all there.

Now all I have to do is get busy and click the descendants that have DNA tested. As I mentioned before, I’ve tested a lot of my family. This is where I usually say that my kids know they aren’t getting an inheritance, just a lot of DNA and genealogy.

All the black spots are people who have DNA tested, and here’s a close-up of the coverage.

So the coverage for my great-grandfather is 61.9%, and if I want to test further, I should test R.F.M., which will bring up the coverage to 71.4%.

R.F.M. makes the most sense because he is from one of the family lines that hasn’t tested at all. Once I have him tested and mark him as tested, then the chart re-evaluates and gives me the next best candidate to test. Pretty cool.

The tool will also change should you find that you have someone in your tree that isn’t living and you hadn’t put that in your tree. You can update the death date on the chart, and the chart re-evaluates.

As I mentioned, you can also manually create the tree, but it’s important to put as many details as possible. So be sure that you have those dates.

Don’t be afraid to use the Gedcom approach because once you download it, you can use it over and over and select others and create more Coverage Estimator charts. (they are kind of addictive). I’m not sure how many charts you can create and if there is a cost for more, but I get such great value from Johnny’s site that it’s worth the subscription cost.

Because I’m always thinking about the Beaton/Batten mystery I decided to download my DNA tree file and then choose the most recent common ancestor that all my DNA matches have as my focus person then I mark all the matches that I know have tested. I believe this will help show me where I have gaps in my research and perhaps some dates that need to be added and to direct me to expand on descendants. It might be a long shot, but although I believe I know who my great-grandfather’s parents were, there are still some matches that I’m just not sure if I’m missing something, and they nag at me.

I encourage you to give this new tool a try and let me know what you think.

✨ If you haven’t DNA tested and you’ve been thinking about it you can purchase your kit through the links on my DNA Comparison page These are affiliate links. This means I make a small percentage of the sales via these links. This does not INCREASE the price you pay as a consumer. This is a supplement to my income so I can support my blog and make donations to the Alzheimer’s Society.

✨ Want to learn more about DNA? You can watch the Legacy Family Tree Webinars series called Foundations of DNA 1-5 They are free to watch, and you just might decide to subscribe to Legacy Family Tree Webinars


  • Bonnie Bossert says:

    Great post and super explanation of how to use this tool when I build trees I put the shared cm in the suffix field I wish Johnny could pick that up and automatically populate the DNA match shared cm