Louis Kessler’s Behold Blog The Behold User Forum
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172.
Triangulation does NOT mean IBD - Blog comment by debbiek - 3 Oct 2017
... by Ancestry's white papers and their transparency about their methodology. I wish FTDNA would do the same.
Parent and child comparisons at FTDNA can't be directly compared with those at AncestryDNA. Each company has different match thresholds:
https://isogg.org/wiki/Autosomal_
173.
Deep Ancestors - Blog comment by jbissett - 2 Oct 2017
... additional capability. Now that DMT can be used for GedMatch results as well as FTDNA, DMT can provide the basis for determining all of the crossover points in a given set of matches for a person's chromosomes. I use both DMT and Steven Fox's Visual Programming spreadsheet, so this information is clearly valuable to me. Presently I will have to have both programs open ...
174.
Deep Ancestors - Blog entry by lkessler - 2 Oct 2017
... it may be possible one day for DMT to identify these for you. David Boyles on the DNA Tools Facebook group asked me to explain this more fully and I thought that was a good idea. The example diagram used in the documentation may not have been the best one to explain this concept because it didn’t have easily identifiable crossovers in it. So here’s a new ...
175.
Triangulation does NOT mean IBD - Blog comment by lkessler - 27 Sep 2017
... My mathematical and statistical background makes me a big hater of inference. And the DNA industry seems to be getting deeper into that all the time. Soon a segment match won't mean anything at all. My reads of AncestryDNA's white papers leave me with little confidence in what they are doing. I've done the same parent-and-child comparison ...
176.
Triangulation does NOT mean IBD - Blog comment by debbiek - 27 Sep 2017
... are widely shared in the ancestral population. We’ve seen this effect at AncestryDNA where, even with phasing, there are still a lot of false positives (or false negatives). See my blog post here:
https://cruwys.blogspot.co.uk/2017/08/comparing-parent-and-child-matches-at.html
This again is mostly a problem with smaller segments under 15 cMs. In my experience, ...
177.
Triangulation does NOT mean IBD - Blog comment by lkessler - 26 Sep 2017
Thednageek (Leah):
Excellent questions, and thank you for them because you're making me really think. I'm hoping to use triangulations to incrementally build up a chromosome map of ancestors the way Jim Bartlett has done and describes on his segmentology.org blog. It is still a work in ...
178.
Triangulation does NOT mean IBD - Blog comment by lkessler - 25 Sep 2017
thednageek: I think Ann beat you by a couple of minutes regarding 23andMe, so I had to give her credit for that update.
Re your 3rd possibility: Whether a segment is from a recent common ancestor or a distant common ancestor, it's still the same segment from the same ancestor that all the ...
179.
Triangulation does NOT mean IBD - Blog entry by lkessler - 25 Sep 2017
When I was first learning about autosomal DNA analysis, just over a year ago, I was under the misconception that if three people triangulate on a segment, then that segment is IBD (Identical by Descent). A segment that is IBD is one that is passed down from a common ancestor. These are the segments you are looking for. By ...
180.
The IAJGS Conference 2017 - Blog entry by lkessler - 31 Jul 2017
... late about 9:30 a.m. I heard the end of Shelley Talalay Dardashti talk describing DNA matching at MyHeritage: At10:30, I listened to Bennett Greenspan tell us about Family Tree DNA. My notes from his talk included him saying: “There will be some new tools coming out in the next quarter or two, like triangulation.” Also of ...
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Triangulation does NOT mean IBD - Blog comment by lkessler - 3 Oct 2017