Tag Archive | Triangulation

MyHeritage DNA Matching: Excellent Enhancements

Apr10

MyHeritage has kept its promises: tree matching, pedigree display, a place for notes, and best of all, a chromosome browser. Plus the cousin matching is finally quite good, at least for your closer cousins, and includes some triangulation.

A very nice new feature is the Ethnicities Map, a menu item under DNA, which gives you the common groups for any modern day country you select. Since a question I commonly receive from family members is “Why doesn’t my known German ancestry show up?”, it is great to be able to show them this map:

A picture says it better than telling them that in the DNA, northern Germans look Scandinavian, southern Germans look Italian, eastern Germans look East European, and western Germans look French. My maternal ancestors lived at the crossroads of Europe!

Uploading your results from another DNA testing company is still free at MyHeritage and you get many of the DNA features. Personally I have just a data subscription and a small tree (there is a 250 person limit for unpaid members). In a few weeks I will create an account for a cousin and see if this works as well as it is supposed to for completely free members.

After the recent change, the segment details for my matches to my close family are very similar to what I see on GEDmatch and 23andme, same chromosomes, similar sizes, slightly different boundaries. This is a wonderful improvement!

Since my ancestors are all fairly recent immigrants from Norway and Germany, I was hoping for some international matches when I uploaded my DNA results to MyHeritage last year. In practice, as usual, there were no Germans (testing is not popular there), but plenty of Norwegian cousins that I already knew about, plus a few new distant ones.

However, I did recently get a new close cousin match (1C2R-2C1R), Melissa from New Jersey. I will use her match to investigate the new improved DNA matching.
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DNA Triangulation 2017 – My Rootstech Talk

Feb2

Rootstech is almost here and I can’t wait. It is not just the great talks that I love but also all the wonderful displays, shows, and tools in the exhibit hall and, of course, seeing old friends. Naturally I am going in a day early to spend time in that wonderful Family History Library, practically next door to the conference!

My talk is about triangulation, a technique used with DNA test results to prove descent from a common ancestor. I hope to see you there, Thursday at 11:00 in the morning in Ballroom J. As always my slides will be posted at slides.com/kittycooper after the presentation.

Wold line cousins Kitty (me), Ed, Marlys

If you have been to previous versions of this presentation, there will be much that is new this time around. It is amazing how much the DNA technology for triangulation has progressed in just a year. Most American 23andme kits are now on the new experience which includes an automated triangulation feature. Plus GEDmatch has added Triangulation Groups (TGs) to its Tier 1 tools.

Furthermore one of the semi-finalists in the RootsTech 2017 Innovator Showdown is a new Double Match Tool from Louis Kessler that provides triangulation for different ftDNA kits that you have the Chromosome Browser Results (CBR) for. Click here for his blog and description of DMT. Genetic genealogy has come a long way!

There is also news for those of you who remember the story of how I used triangulation to confirm a thin paper trail and prove that Kristine is my Wold side cousin (click here for that blog post and here for the follow up). The DNA test for Marlys, one of Charlie’s 26 grandchildren, came in and provides further proof. Not only that but Marlys had known the story all along about that first child of Charlie’s!

A Triangulation Feature on the New 23andme

May26

An exciting triangulation feature is available at 23andme.  This feature shows you the relatives you have in common with one other profile and whether or not they triangulate with the two of you.

To use this tool you go to  Family & Friends > DNA relatives  and pick a DNA relative to look at. Scroll down the page towards the bottom where you will see a display like this (names removed for privacy): [previous 2 paragraphs updated 10 May 2019]

RICsmll

When there is a “Yes” in the right hand column, there is a DNA segment in common between the two people you are comparing and this third person thus you triangulate. A “No” means that although you each share DNA with this relative, there is no segment of DNA where all three of you match. Click on the Yes (or a No) to see the three of you compared in the chromosome browser.

Once in the chromosome browser, you can use the “Update View – Edit” to add more people to the comparison with the first person. This is the same chromosome browser that you get to from Tools > DNA relatives > DNA

Jason Lee has done a nice write up with more details on his DNA blog at Tumblr:
http://dnagenealogy.tumblr.com/post/144966221253/relatives-in-common-quick-reaction

 

More on the SCGS Jamboree: Free Live Streaming

Jun6

I am very grateful that Ancestry.com has sponsored live streaming of the Jamboree since my foot problems are keeping me home now. There is one selected presentation available in each time slot.

TriangulationSlidesSee the schedule here: http://genealogyjamboree.com/2015/schedule-streaming.html and how to get set up for it here http://genealogyjamboree.com/2015/streaming-overview.html

I really enjoyed my day and a half at the Jamboree. I discovered that most of the San Diego folk had come by train! There is a stop next door at the Burbank Airport and the hotel has a van that will fetch you. Next year …

As always I loved listening to Cece Moore. I learned a few things from her presentation about some of her adoptee success stories. Many more genetic genealogy stars were there: Blaine Bettinger, Tim Janzen, Angie Bush, Judy Russell, and Kathy Johnston. Sadly I had to miss most of their presentations since I gave two of my own.

I was pleasantly surprised by the full house at my triangulation lecture. It was exciting to be live streamed. A number of folk told me afterwards that they felt like they finally understood this concept. What I did was present a number of real life cases from my own research where I used DNA triangulation to figure out relationships. That seemed to work well.

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Triangulation: Proving a Common Ancestor

Feb26

The same question seems to come up over and over again among those new to autosomal DNA testing. If I match A and B on the same segment why is that not enough to prove they match each other and we have a common ancestor?

The reason the ancestor is not proven is that you have two strands of DNA on each chromosome (remember there are 23 pairs of chromosomes) and the testing mechanism cannot differentiate between the two of them. So A could match the piece from your mother and B could match the piece from your father or one of them could even be a false match to a mix of alleles from both parents (see my post on IBC for more on that concept)

The way to prove the common ancestor is to see if A and B match each other in the same place that they match you. This is what we call triangulation.

Triangulation example

Kristine’s shared DNA with other Wold descendants, relationships are to her (to me in parenthesis)

About a year ago I blogged about how, after many years, a change in spelling on the paper trail had led fellow genealogist Dennis to think his wife Kristine was perhaps descended from my great-grandmother’s brother Carl. To prove this I suggested he test her autosomal DNA.
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