Recreating An Ancestor’s DNA with DNA Painter

DNA Painter is a wonderful resource to map segments of your DNA by family.

While it’s typically used to map a single DNA test taker’s matches, I’ve found a very interesting thing you can do. If you have multiple relatives test, you can aggregate their DNA together to bring an ancestor’s DNA “back to life.” Essentially, you’re creating a profile from their perspective.

For example, even though my paternal grandfather never DNA tested, I was able to reconstruct much of his DNA through his descendants who did. Here’s a look at my grandfather’s Chromosome 7, both paternal and maternal, almost entirely mapped (see graphic above).

Through this process, I phased back to his grandparents. Dark green is from his paternal grandpa, light blue is from his paternal grandma, purple is from his maternal grandma and lime green is from his maternal grandpa.

How did I get there? First, three of his children DNA tested. I visually phased their DNA with known cousins to determine where they inherited from their father’s father and where from their father’s mother. Then, since a sibling of my grandfather tested, I compared those segments with him; Phasing with cousins, I determined which of my grandfather’s grandparents he inherited from.

Practically, this may not be necessary to make key discoveries. But it is fascinating to see how much of an ancestor’s DNA you actually have to work with. And it’s a great way to visualize their DNA, breaking down what they inherited from their mother, their father, their grandparents, and what they share with their aunts and uncles. The first time you achieve this for an ancestor, it’s really eye-opening.

In terms of what you’ll need to achieve this, ideally a minimum of:

  • 2 or 3 siblings, who descend of a target ancestor so you can do visual phasing to map the DNA they inherited from each grandparent
  • 1 or 2 first cousins, who descend of the target ancestor – again, you will do phasing to see DNA inherited from common ancestors
  • Any second cousins or beyond who descend of the target ancestor (for more distant target ancestors)
  • Siblings or first cousins combined with an aunt or uncle – this helps to phase
  • A combination of all of the above

The more descendants of a target ancestor who tested, the better. You will also need known cousin matches to help with the phasing process, narrowing down the side shared.

You create a profile for your target ancestor at DNA Painter. As you identify and confirm segments that must have passed down from the target ancestor, you can paint them. To speed up the process, it is easiest to download the Import template provided by DNA Painter under Settings and manually input start and end points for each segment (though a subscription to DNA Painter is required for import functionality). If you are not sure if it is paternal or maternal for the target ancestor, you don’t have to assign that yet. Eventually you may be able to tell.

I recommend labeling the name of each “match” as the descendant who inherited that DNA. You will begin to see which descendants inherited which segments from the target ancestor, and in the process you’re painting their DNA.  Each segment from a target ancestor comes from their father or their mother, so the next part of the process is determining which side for each segment.  Some larger segments will break into smaller segments, with some from the father, some from the mother, so that’s important to keep in mind too.

It may seem daunting at first, and it certainly does take a lot of time to do it correctly. But it can be done. The key: take it one step at a time. One kit at a time. Over time, you’ll get a more full picture.

Through this process, I’ve learned that I have 92% of my paternal grandpa’s DNA through his descendants who tested. I also did this with my great-grandparents, and I have 81% of his father’s DNA and 78% of his mother’s DNA.

You can go all sorts of direction with this. Here are segments of my grandpa’s DNA phased back to his great-grandparents (made possible by multiple cousins testing), each represented by a different color:

Of course, if only I tested, I would have a much smaller fraction of DNA from these ancestors, so it shows the value of testing as many descendants and older relatives as possible. While close relatives have many segments in common, we inherit different pieces of DNA from our ancestors that would otherwise be lost.

Have questions about this process or wondering how you might be able to apply it in your own research? Scroll down and leave a comment below.

Looking for other ways to take your DNA results to the next level? Have a look at these:

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2 comments on “Recreating An Ancestor’s DNA with DNA Painter”
  1. Patrice says:

    Interesting. It does sound daunting, but I will check it out.

    Like you I’m researching Irish genealogy, which necessitates a lot of edgy strategizing. I discovered my own Irish immigrants only in 2016, via DNA and a nice bit of luck: a descendant of my great-grandmother’s birth mother was on AncestryDNA, and I’d pieced together just enough clues to recognize a potential in him (getting him onto GEDmatch with its tools clarified the match). Long story ….

    Working back from a Famine immigrant, most of my family’s Irish matches share only small segments. (Our immigrant, Bridget Mannion, had only one child who survived to adulthood, and that girl had only two children — my great-grandmother and a son, whose descendant I met on Ancestry. So there aren’t a lot of close cousins out there.) Just this morning, reading about the discouraging statistics of relying on small matches, I wondered whether I could combine the GEDmatch-phased segment reports of my siblings and myself into a single report in lieu of phasing my 90-year-old father’s dna. He has no living siblings, and his parents are long dead, but he has three children and a family of three tested nieces who I can work with. Plus the DNA of his half-aunt, who contributed it at age 100. Her DNA was instrumental in my identifying her own mother’s birth mother. (Her mother — my great-grandmother — had been adopted in 1880. How’s that for a cold case?!)

    So much database work! Not my natural proclivity, but I’ll go there, if I can reap a reward. 🙂

    Thanks for the ideas and the inspiration, Craig!

    Liked by 1 person

    1. Wonderful work, Patrice! I really enjoyed your story. DNA has definitely opened up all kinds of doors that were simply not possible in the past and yours is a perfect example. Happy to share these ideas!


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