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When an Ancestry DNA green leaf is wrong

By Richard Weiss, Director of Programs, DNAadoption.com

Ancestry.com does a great job of finding common ancestors between DNA matches when both parties have trees. The layout is easy to navigate, intuitive, and well integrated, but sometimes the WRONG person or couple is shown as providing the shared DNA. This problem can occur when you share multiple common ancestors with a match but you or your match have have not yet found all of them.

Let’s look at an example of this.

In September 2016, I received a new match at AncestryDNA – B41. Based on a comparison of B41’s tree and my tree, Ancestry provided a “Shared Ancestor Hint” indicating that Barnabas Pratt was our common ancestor and that we were 5th cousins three times removed (5C3R) as shown below.

richardcaseb41

Figure 1: Ancestry’s “Shared Ancestor Hint”

Note that Ancestry’s “Shared Ancestor Hint” in the above image indicates that B41 and I match through my paternal side.
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My Perfect Cousin

This is the first time I have had a cousin’s DNA test come out showing an ancestry composition that was 100% a single ethnicity. My cousin J.M. was not in the least bit surprised as she expected to be all Scandinavian. Five of her eight great-grandparents were born in Norway and the other three were born in the U.S.A. to Norwegian immigrants. But I was quite surprised because there is usually at least a trace of something else.

jmethnicitysmllShe shares my Norwegian born Munson (Monsen) great-grandparents as her great-great-grandparents making us 2nd cousins once removed. She tested at AncestryDNA to help me figure out where a related adoptee might fit in (no luck on that). The fact that she has a genetic genealogist for a cousin who would tell her what it all meant helped convince her as well.

I usually send cousins to my page comparing all the autosomal tests and let them choose. However I prefer Ancestry.com DNA testing for the interested, but non-genealogically serious, relatives who are online because it is so easy to see the relationships and use the green leaf hinting system. Also I was tired of having only one circle and her test would give me a second one. Those with colonial ancestry have plenty of circles and NADs (New Ancestor Discoveries) but we recent immigrants (1870s and 1880s) are lucky to have any. Last but not least, it was the cheapest test at the time she ordered it.

Now why is she perfect? It is not just the 100% Scandinavian but amazingly her top four matches are all second cousins from different pairs of great-grandparents! I have never seen that before either. Of course most of my tested relatives being from relatively recent immigrants, have no second cousins and almost no thirds showing at Ancestry .

Here are J.M.’s matches:

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New Ancestry kit in from my Wold cousin

You know you have an obsessive personality when a cousin’s DNA results come in and you put off as many plans as you can for the next 3 days in order to explore them. At least I have some observations to report on the new Ancestry chip as well as more data for my study of the Wold family.

Wold line cousins Kitty, Ed, MM

Wold line cousins Kitty, Ed, MM

According to Ancestry, this new chip has dropped some less interesting SNPs and replaced them with medically relevant ones as well as ones more useful for determining ancestry composition. The details are at http://blogs.ancestry.com/techroots/customer-testing-begins-on-new-ancestrydna-chip/

GEDmatch only tokenized 455K of the 700K SNPs from that new chip. However when I imported the raw data into a spreadsheet I saw that there were 668,961 lines of data as opposed to the previous 701,495 (then subtract 20 for the header), so not that different a number. New is chromosome 26 which is for the mitochondrial DNA.

My Wold cousin MM is the cousin whose doorstep I arrived on, Ancestry kit in hand, because I really really wanted her results. Those of you who have been to my Triangulation talk or read the article here may have noticed that I had no other cousins tested who are descended from my great-grandmother’s brother Charlie, the one presumed to be Kristine’s great-great-grandad. MM’s test has rectified that although she is descended from a different wife of Charlie’s than Kristine.

Since MM is the half first cousin of Kristine’s grandfather, she and Kristine are half first cousins twice removed. Do they match at the expected level?

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Christmas DNA Sales are here!

Family-Tree-DNA--Gift

Existing ftDNA customers get coupons

Both Family Tree DNA ($89) and AncestryDNA ($79) have Christmas sales for their DNA kits (those prices do not include shipping). I think the Ancestry.com DNA testing sale will last only until November 20th. Family Tree DNA‘s sale is on until the end of the year. In contrast 23andme just doubled their price but is adding new interfaces and health results.

Family Tree DNA  has special gift coupons for existing customers; so log in every week and see what you have. Roberta Estes suggested that people could put their unwanted codes in the comments on her detailed post about the ftDNA sale. That seems like a good idea to me. You can do that here too, but please indicate in a reply to each coupon comment when you have taken that one. I will list a few of my coupon codes also.

I have written up my recommendations for where to do your DNA testing on my comparison page. Here is a summary of my current thoughts on which company to use.

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Please upload your ancestry DNA data to a site with a chromosome browser

Today I sent the following email to a newly found DNA cousin match at ancestry whose great-grandmother lived right next door to my family in Kristiansand, Norway in the late 1800s. She moved to the U.S.A just a year after they did (1884 and 1885) and lived a block away from where my grandad eventually lived on Ovington Ave in Brooklyn, N.Y.

Monsen Home KristiansandDear cousin,

OK now I REALLY want to see where our DNA matches, because I have a large database (spreadsheets) of where my Dad, my brother and I match various known Norwegian relatives so it is likely that I can figure out from the matching DNA segment(s) where we are related and if it is really the 7th cousin match shown at Ancestry.com on the Eigeland line.

Pretty please either upload to GEDmatch or Family Tree DNA or both.

First you will need to get the raw data from Ancestry.com – here is how:

UPDATE 15-Aug-2018: Roberta Estes has published a step by step on how to do this: https://dna-explained.com/2018/08/15/ancestry-step-by-step-guide-how-to-upload-download-dna-files/ Continue reading