Louis Kessler’s Behold Blog The Behold User Forum
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212.
The Life and Death of a DNA Segment - Blog comment by lkessler - 21 Aug 2019
Jonathan: I don't understand your logic why a 6 cM limit means that the 15 cM wasn't born in some ancestor, but got longer. It's always a recombination that creates a new segment. Whether it or parts of it are filtered out by the company doesn't seem relevant to me because the filtering is only done in the DNA ...
213.
The Life and Death of a DNA Segment - Blog comment by jonathanb - 20 Aug 2019
Nice writeup, I've been waiting for someone to talk about this.
There's a corollary that you didn't talk about. Ancestry has a 6 cM minimum size for matching segments. Any segment under 6 cM might as well not exist, as far as Ancestry's matching algorithms are concerned. Other sites use slightly different ...
214.
The Life and Death of a DNA Segment - Blog entry by lkessler - 19 Aug 2019
There’s a bad rumor going around that segment matches, especially for small segments, can be very old. I’ve heard expectations that the segment might come from a common ancestor 20 generations back or even 30, 40 or more. And that’s said to happen even if you have a fairly large 15 cM segment. Part of ...
215.
Comparing Raw Data from 5 DNA Testing Companies - Blog comment by lkessler - 18 Aug 2019
Yinwang: The general method of imputation is to use samples from a population that best fit known values to fill in missing values. Imputed values will thus not catch many variants, and may result in non-matching segments with close relatives who should match and matching segments with people who shouldn’t ...
216.
Comparing Raw Data from 5 DNA Testing Companies - Blog comment by yinwang888 - 17 Aug 2019
This is super interesting and well done. I think ultimately the double position and double rs-ids problem are to blame on dbSnp the underlying public database. I have heard many professional geneticists say that they now only use chr:pos:A1_A2:built as ID because of this frustration (that’s “chromosome” , ...
217.
50 Years, Travelling Salesman, Python, 6 Hours - Blog entry by lkessler - 7 Aug 2019
This is my first blog post in over 2 months. The reason is that I have been working very hard trying to finish Version 3 of Double Match Triangulator. Every thing I’ve been doing with it is experimental, and there’s no model to follow. So it’s tough to get it just right. I started the documentation of the ...
218.
Combine Kits into One Superkit on GEDmatch Genesis - Blog comment by lkessler - 5 Aug 2019
Cdxp: Yes, the parent company of Family Tree DNA is Gene by Gene, and their testing facility in Houston does both Family Tree DNA and MyHeritage. Gene by Gene changed recently to a new chip that allows for some custom selection of SNPs. Family Tree DNA and MyHeritage have different custom SNPs, with MyHeritage ...
219.
Combine Kits into One Superkit on GEDmatch Genesis - Blog comment by cdxp - 5 Aug 2019
Are FTDNA and Myheritage using the same testing facility? Some recent advertising and your results suggest a relationship of some kind. I've just purchased DNA tests from both to try and get more coverage than i get from LDNA but perhaps that is duplication.
220.
My Whole Genome Sequencing. The VCF File - Blog comment by lkessler - 13 Jul 2019
Jarett, no, I wrote all the code myself. Double Matching is a technique I've never seen used before, so I'm discovering new ways to utilize it as I go.
Prev 201-210
The Life and Death of a DNA Segment - Blog comment by jonathanb - 21 Aug 2019