DNA Coverage Estimator is a great tool from DNA Painter to help you estimate how much of your ancestor’s DNA is accounted for via testing of descendants. Want to learn how to use it? Keep reading to see how Diahan uses the DNA Coverage Estimator on her great-grandmother’s DNA.

We spend a lot of time talking about how much DNA we share with our DNA cousins. But we rarely talk about the amount of DNA that a certain ancestor has documented. Essentially to be able to ask the question: How much of my ancestor’s DNA is currently sitting somewhere in a DNA database?

This question is worth asking on its own, but working to increase the representation of your ancestors in our databases will have long-lasting implications as DNA testing becomes even more sophisticated. 

DNA Coverage Estimator

But enough of me peering into the future. Let’s look at this tool from DNA Painter that helps you estimate the coverage of your ancestor’s DNA! For this example, I am going to be looking at my great-grandmother Clara Louise Rasmussen. She is especially important (in DNA terms) as she was an only child. So there aren’t any other siblings to help me gather the DNA of her parents. She is it. Which means each of her descendants is even more important to documenting her family.

You can get all the ins and outs of how to use the Coverage Estimator tool right from the mouth of Jonny Perl himself, so I will just run through my experience to give you an idea of what you can learn when you use it.

I have set up the tree to show all of Clara’s children and grandchildren, and marked those who have tested.

First, does that 100% figure for the DNA testers stick out to you? It should! It is always a good reminder to ourselves that we are 100% US. By testing ourselves, we are representing 100% of our DNA.

You can see at the top that the tool is suggesting I test Lucille and Ernest. Well, they have passed, so I need to use the Add/Edit details to add those death dates so it can give me proper suggestions.

Notice how it is suggesting that I test Richard and Gary? This is because none of my aunt Lucille’s descendants have tested, so they will add the most to our representation of Clara. 

It is also worth noting that even though I have tested (as has my cousin Tara) we add zilch, zero, nada to this estimate, as our parents have each been tested, as illustrated below.

It is also worth noting that even if I can get all of the grandchildren of Clara tested, I will still only be able to represent 84.7% of her DNA. Ever. But that is a fair bit better than the 64.8% I currently have, so I am more motivated than ever to get these remaining cousins tested. 

Sadly, because she is an only child, even if I get 85% of her represented in the database, that will only be about 43.5% of each of her parents. Unfortunate, but good to know.

If you are into the really interesting math behind all this, I recommend this blog post from Leah Larkin who helped develop this tool.

Just remember, the greater the DNA coverage you have for an ancestor, the better able you are to tell their story!

Get more out of your DNA results with the many tools at DNA Painter. This is just one of them. Some of the tools (like this one) are available for free, but you’ll want to subscribe to get the most out of them. You can sign up for an annual subscription to DNA Painter with an exclusive discount (thanks, Jonny!).*

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