Tag Archive | DNAgedcom

Automation to Find the Common Ancestors in the Trees of your DNA Matches

Recently I gave a presentation on many of the great new DNA tools that have come out this year. The talk focused on how both Ancestry and MyHeritage figure out the likely ways in which you are related to a DNA match from the other trees on their sites (click here for my slides). This left very little time to go into the details of my favorite third party tools that can do similar magic, so I promised the attendees a blog post…

The three tools I use the most for finding common ancestors are:

They all have their strengths but none are free. Think of the endless hours professional programmers have spent making these tools and be grateful.

Mainly I use them for unknown parentage cases where the tree is not yet known. However they are also useful for your genealogy. For example, Genetic Affairs will look at the trees on Family Tree DNA and show you any common ancestors it finds with the path to your matches:

My Dad shares DNA with many descendants of this couple as shown by Genetic Affairs from his FtDNA results

There are many other tools I could not do without, like the online relationship calculator at DNApainter (click here) but this article is about automation to find common ancestors. Read on for my summary of the strengths and weaknesses of each of the tools that do that.

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Talking About Many New DNA Tools

Tuesday I will be presenting the latest version of my talk on solving unknown parentage cases in a virtual conference hosted by the Utah genealogical society (click here for more information). In the past, I relied heavily on the tools at DNAgedcom, but now there are several new tools that are even more exciting.

The basic methodology for unknown parentage searches is to DNA test everywhere. Then look through the trees of your matches to see what ancestors are in common. Build trees down from those common ancestors looking for where the different families meet in a marriage. Then find a child of that marriage who was in the right place at the right time to be the missing parent or grandparent or …

A major difficulty is that many people test DNA without providing a tree. Usually you have to try to build trees for them. Another problem is that building trees down from those common ancestors is incredibly labor intensive when the families are large and the matches are distant. My latest strategy for difficult cases is to recruit several search angels to build the different trees.

There are now tools that automate building trees!
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Another Unusual DNA Adoptee Case

Janice was searching for her biological father. Her Ancestry DNA test had found what looked to be an aunt or half aunt, “ Sally,” and also a half uncle, “Trevor,” who did not match each other, both about 20 years older than Janice. So likely each of them was related to one parent of the unknown father. This could be easy! But wait…

Display from Ancestry Beta match view: Note that the common ancestor with Sally came after adding her tree

Notice the difference in matching DNA and that they are both listed as 1st-2nd cousins. Yet both are in the range for half aunt/uncle (500-1446 cM). Although other relationships, like first cousin were possible, they did not fit the known facts or the matching to common relatives. Trevor’s second cousins shared with Janice were all showing as third or fourth cousins to her, suggesting one generation of difference. The same was true for Sally’s closer cousins: her firsts were coming up as Janice’s seconds.

Trevor, born 1945, had just discovered via his Ancestry test that the father who had raised him was not his biological dad. His dad was actually his stepfather; he had adopted him when marrying Trevor’s mother. Sadly she was no longer available to tell Trevor who his birth father really was and the father of record did not fit the DNA evidence.

Sally knew that her mother had given birth to a boy in 1944 that had been adopted out. This child was not the son of the man she later married; his father was unknown. Sally had tested her DNA hoping to find her half brother and was excited to have found his daughter!

How Sally and Trevor are related to Janice

The problem here is that since Janice’s father is that adopted half brother, there may be no way to track him down. The best I could do for Janice was to find Trevor’s dad and Janice’s paternal grandfather via DNA. Since he had deep American roots it took less than four hours! That is of my time, but actually a day and a half of elapsed time.

Here is how it was done.
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More Automated DNA Match Clustering!

Have you been wondering why are all your favorite bloggers are going crazy for automatic clustering? Well it is a fun visual technique to see which matches belong to which family line by making a chart with your matches across both the top and side, grouping them by who matches who, and then coloring those boxes in. This creates visual clusters which will roughly correspond to your great grandparents or their parents.

My perfect cousin has many matches on all her great grandparent lines (green is my Munson side) so I used her to showcase the new DNAgedcom clustering above. Notice how similar it is to her cluster from Genetic Affairs shown in my previous blog about that site and tool.

Here are all the new ways to cluster our DNA matches:

  • DNAgedcom now has a clustering tool in their client (DGC) which uses your ancestry match list and ICW files (described in detail in the read more below)
  • Genetic Affairs has Ancestry clustering working again
  • DNApainter created a tool to create a CSV from the Genetic Affairs html cluster file. Some of us love to use spreadsheets.
  • Andy Lee of Family History Fanatics figured out how to take an autosomal match matrix from GEDmatch and cluster it in a spreadsheet program, Click here for that video – the explanation starts just after 42 minutes and this is really fun!
  • Rumor has it that GEDmatch may add automatic clustering sometime in the new year…

All of this is based on the method developed by Dana Leeds to organize your matches which is easy and simple to do. Click here for her blog about that.

Read on for how I used the new DNAgedcom clustering tool for myself and my brother, where I know all our great grandparents.

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Eliminating the DNA Matches from One Side

UPDATE 26-Oct-2018: Click here for this tool  –  Extract Desired Lines

Unless you get lucky with a first cousin or closer match, searching for an unknown parent or grandparent involves building lots of trees for your DNA relatives and looking for common ancestors among them. Then you build down from those ancestors looking for someone in the right place at the right time. It is best to have two pairs of common ancestors because then you are looking for where their descendants meet in a marriage.

Sample ancestor list from GWorks – linked to slide in my GWorks presentation – using-dna-for-adoption-searches

It is wonderful to have automation to compare trees for you. The GWorks tool suite from DNAgedcom.com does just that and, no surprise, I have written many blog posts about how to use those tools. They can collect all your Ancestry matches and then all the ancestors in their DNA connected trees and give you a list of the most frequently seen ancestors. You can also upload GEDcoms collected elsewhere or created by your own research to use in the comparison.

There are many times I would like to automatically exclude half the ancestors collected from Ancestry. For example when I am helping a person who knows only one parent but has a half sibling or the known parent tested. Specifically when they look at the results from a GWorks run, how do they eliminate the matches from the other side?

View Trees with an example for deleting

One way is to go to the “View Trees” on the GWorks menu at DNAgedcom and delete all the trees from the known side by clicking the red X to the far right of each tree. Then rerun the “Match GEDcom files” in the Manage Tree Files function. This could take forever in a half sibling case.

However, it is very useful to delete trees when one person has tested multiple family members and they are all in the same tree. In that case I keep the tree for the person who is further up the line. Very conveniently you can click on the tree name to go to that match at Ancestry, as long as you are logged in there, so you can easily figure out which one to keep. But again, this is too lengthy a process for a half sibling case.

DNAgedcom client home window

I have long used the Match-O-Matic (M-O-M) feature in the DNAgedcom client (DGC) to get the lists of matches for just one side (the m_ file) in a spreadsheet for use to keep track of my research. However M-O-M does not work for the tree files (aka the a_ file – actually it has a list of ancestors and which trees they are from).

Sometimes it is good to be a programmer. I have put together a new tool that you can use with a list of matches, for example the match file from M-O-M, to create a new tree file with only those trees that are for the matches in the match file. Then you can upload that match file and the new tree file to DNAgedcom for use in GWorks.

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