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Ancestor Reconstruction

Roberta Estes

No, this is not Jurassic Park and we’re not actually recreating or cloning our ancestors – just on paper.

Back in early 2012, I began to discuss the possibility of using chromosome mapping of descendants to virtually recreate ancestors.

In 2013, I wrote a white paper about how to do this, and circulated it among a group of scientists who I was hoping would take the ball and run, creating tools for genetic genealogists.  So far, that hasn’t happened, but what has happened is that I’ve adapted a tool created by Kitty Cooper for something entirely different than its original purpose to do a “proof of concept.”

Kitty Cooper created the Ancestor Chromosome Mapper to allow people to map the DNA contributed by different ancestors on their chromosomes.  It’s exciting to see your ancestors mapped out, in color, on your chromosomes.

I utilized Kitty’s tool, found here, to map the proven DNA of my ancestors, below, utilizing autosomal matching and triangulation, to create this ancestor map of my own chromosomes.  As you can see there are still a lot of blank spaces.

After thinking about this a bit, I realized that I could do the same thing for my ancestors.

The chromosomes shown would be those of an individual ancestor, and the DNA mapped onto the chromosomes would be from the proven descendants that they inherited from that ancestor.  Eventually, with enough descendants we could create a “virtual file” for that ancestor to represent themselves in autosomal matching.  So, one day, I might create, or find created by someone else, a DNA “recreated” file for Abraham Estes, born in 1647 in Nonington, Kent, or for Henry Bolton, born about 1760 in England, or any of my other ancestors – all from the DNA of their descendants.

I decided a while back to take this concept for a test spin.

I wanted to see a visual of Joseph Preston Bolton’s DNA on his chromosomes, and who carries it today.  I wrote about this in Joseph’s 52 Ancestors article.

Utilizing Kitty Cooper’s wonderful ancestor chromosome mapping tool, a little differently than she had in mind, I mapped Joseph’s DNA and the contributors are listed to the right of his chromosome.  You can build a virtual ancestor from their descendants based on common matching segments, so long as they don’t share other ancestral lines as well.  I have only utilized the proven, or triangulated DNA segments, where three people match on the same segment.

We have a couple more DNA testers that descended from Joseph Bolton’s father, Henry Bolton through children other than Joseph Preston Bolton.  Adding these segments to the chromosome chart generated for Joseph Preston Bolton, we see the confirmed Henry Bolton segments below.

On the chart above, I’ve only used proven segments.

On the next chart I have not been able to “prove” all of the segments through triangulation (3 people), but if all of the provisional segments are indeed Bolton segments, then Henry’s chromosome map would have a few more colored segments.  Clearly, we need a lot more people to test to create more color on Henry’s map, but still, it’s pretty amazing that we can recreate this much of Henry’s chromosome map from these few descendants.

There’s a lot of promise in this technique.  Henry Bolton was married twice.  By looking at the DNA the two groups of children, 21 in total, have in common, we know that their common DNA comes from Henry himself.  DNA that is shared between only the groups descended from first wife, Catherine Chapman, but not from second wife, Nancy Mann, or vice versa, would be attributed to the wife of the couple.  Since Henry was married twice, with enough testers, it would be possible to reconstruct, in part, at least some of the genome of both wives, in addition to Henry.

Now, think for a minute, a bit further out in time.

We don’t know who Nancy Mann’s parents are for sure, although we’ve done a lot of eliminating and we know, probably, who her father was, and likely who her grandfather and great-grandfather were….but certainty is not within grasp right now.

But, it will be in the future through ancestor reconstruction.

Let’s say that the descendants of John Mann, the immigrant, reconstruct his genome.  He had 4 known sons and they had several children, so that would be possible.  John, the immigrant, is believed to be Nancy’s great-grandfather through son John Jr.

Now, let’s say that some of those segments that we can attribute through Henry Bolton’s children, as described above, are attributable to Nancy Mann.  The X chromosome match above is positively Nancy’s DNA.  How do I know that?  because it came through her son, Joseph Preston Bolton, and men don’t inherit an X chromosome from their father, only their mother.  So today, 3 descendants carry that segment of Nancy Mann’s X chromosome.

Let’s say that one of the Nancy Mann’s proven DNA segments (not the X, because John didn’t give his X to his son John) matches smack dab in the middle of one of the proven “John Mann” segments.  We’ve just proven that indeed, Nancy is related to John.

Think about the power of this for adoptees, for those who don’t know who their parent or parents are for other reasons, and for those of us who have dead end brick walls who are wives with no surnames.  Who doesn’t have those?

We have the potential, within the foreseeable future, to create “ancestor libraries” that we can match to in order to identify our ancestors.  Once the ancestor is reconstructed, kind of like reconstituting something dehydrated with water, we’ll be able to utilize their autosomal DNA file to make very interesting discoveries about them and their lives.  For example, eye color – at GedMatch today there is an eye color predictor.  There are several ethnicity admixture tools.  Want to know if your ancestor was ethnically admixed?  Virtually recreate them and find out.

Once recreated, we will be able to discover hair color, skin color and all of the other traits and medical conditions that we can today discover through the trait testing at Family Tree DNA and the genetic predispositions that Promethease reveals.

Yes, there will be challenges, like who creates those libraries, moderates any disputes and where are they archived for comparison….but those are details that can be worked out.  Maybe that’s one of the new roles of project administrators or maybe we’ll have ancestor administrators.

Someday, it may be possible to construct an entire family tree from your DNA combined with proven genealogy trees – not by intensely laborious work like it’s done today, but with the click of a button.

And that someday is very likely within our lifetimes, and hopefully, shortly.  The technology and techniques are here to do it today.

I surely hope one of the vendors implements this functionality, and soon, because, like all genealogists, I have a list of genealogy mysteries that need to be solved!!!

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