Tag Archive | genetic affairs

Can ethnicity help with unknown parentage?

Recently ethnicity was a major factor in figuring out the family of the mystery father of an Australian women of mixed heritage: Chinese, Italian, and English/Irish. We still need some help, so any Australian readers please read to the end.

Elana’s ethnicty on Ancestry after the update, before she had lots more Italian

This case is unusual because for those of us with primarily European ancestry, the ethnicity predictions from the various DNA test companies are not accurate enough to be a significant aid with figuring out unknown parentage situations. For one thing, our ancestors moved around more than you might expect, and for another, the science is just not exact enough yet.

Too often I get a panicked email or comment from someone who is worried that Daddy is not their dad, or perhaps grandad is not, because their ethnicity predictions show no German or French or Bulgarian which he was and where is that Norwegian from? To which I respond, check your matches, if you have matches to cousins from his family, all is well, it’s just the inaccuracy of ethnicity predictions. North Europeans and South Europeans are fairly distinct from each other, but countries as we know them today did not exist in the far past.

Comparing ethnicities for Elana (left) and her mother (right) at Ancestry

In Elana’s case, having East Asian and Southern European in addition to the usual Australian British mix, actually gave us some different and potentially useful data to work with. Her mother seemed entirely English, Welsh, Scottish and Irish, a frequent blend for an Australian. She remembers that Elana’s father said he was part Maori and that his name was Bob. There is no Maori in her results shown above (it usually looks Polynesian), so likely he was just trying to make himself seem exotic and interesting.

Elana’s best matches at ancestry were almost all maternal (yes this is a squashed image)

Since Elana’s mother tested also, we could see that Elana had no close matches that were not listed as “Mother’s side” on Ancestry which made the search very difficult. Her paternal matches consisted of only one 3rd cousin, an American of Italian ancestry, and lots of 4th cousins, quite a few with trees, and most of the closer ones were of Italian descent, in spite of only 7% Italian listed in her Ancestry ethnicity.

One possibility for so few paternal matches was related parents. We checked that by uploading to GEDmatch.com (click here for my post on related parents) and that was not the case. The other more likely explanation was very few of her father’s relatives had tested. For example, Elana had only one very distant Asian match in spite of her father clearly having half that heritage.

Since we could see both Elana’s ethnicity and her mother’s it was easy to tell that Elana’s unknown father was half Chinese/Korean with an Italian (great) grandparent. These were her initial percentages before the recent update at Ancestry:

65% England/Scotland/Wales (so her father will have about 15%)
16% Korea and Northern China
12% China
7% Italy

I asked Elana to also test at 23andme and to upload her Ancestry results to MyHeritage and Family Tree DNA as well. Still no luck finding close paternal matches.

 

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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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More Clustering Tools!

There are many new ways to make those beautiful cluster diagrams of how your DNA relatives are related to each other. Both MyHeritage and Gedmatch GENESIS (tier 1) now have clustering tools (Thank you Evert-Jan Blom). These charts give you an easy way to see your family groupings and can help you figure out a new match since each cluster typically represents a common ancestral couple. Click here for my previous posts on clustering which is based on the Leeds method.

My Dads Clusters at Gedmatch GENESIS

The GENESIS cluster diagram shown above includes the total cM each match shares with you as well as their name and kit number. Click on the “i” in a circle for a pop up box with the user information which includes an email address and whether a GEDmatch tree is linked to this kit. Any of the colored boxes on the graph can be clicked to open a window for a one to one comparison between those two people. Plus you can check the boxes in the select column for any number of matches and then submit them to the multi kit analysis using the orange “Submit to Multi Kit Analysis” button above the name column on the left. To get this clustering tool all you need is a Tier 1 membership and a kit number. It is listed at the bottom of the Tier 1 tools. Personally I like to raise the thresholds to a top 200 and a minimum of 20, but try the defaults first and see what is best for you.

One of the nice things about the cluster output from Genetic Affairs is that it lists all the cluster members in groups below the graph with the number of people in each tree (clickable) and any notes you made on the Ancestry profile. The MyHeritage version also has those cluster lists with your notes and the tree sizes; and of course they are clickable to the match (which may even have a theory of family relativity for you!) and the match’s tree. The down side is that you cannot select the parameters for the clustering yourself, they are preset. Possibly only power users care about that!

Extract from my list of matches in each cluster at MyHeritage

An exciting new feature for those looking for one unknown parent or grandparent is the ability to cluster just your starred Ancestry matches when using the clustering tool at Genetic Affairs.  Click here for my previous post about that tool. There now is a checkbox on the page where you select your parameters for getting a cluster analysis.

Newat Genetic Affairs is the checkbox for only starred matches when starting a cluster analysis

It is a common practice to star (mark as favorites) the matches that seem to be from the family of an unknown parent or grandparent at Ancestry. Usually these are determined by looking at who matches or doesn’t match a close relative like a half sibling or else by eliminating matches from the known side. Sometimes you can use ethnicity. I am currently helping someone where the known side is Jewish and the unknown side is Italian and those are easy to separate.

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