About

Jim Bartlett has been a genealogist since 1974. He started the BARTLETT DNA Project at FamilyTreeDNA in 2002. Soon thereafter he began teaching DNA to various genealogy groups in MD, VA, DC, WV, etc.  In 2010 Jim took his first autosomal DNA test at FamilyTreeDNA, followed shortly by atDNA tests at 23andMe and AncestryDNA. Jim has become a huge fan of the Triangulation process and chromosome mapping – the ultimate human puzzle. This site was set up to document information about segments and autosomal DNA.

13 thoughts on “About

  1. I am new to DNA and have tested at Ancestry.com and FTDNA. I greatly appreciate all this information. I intend to study it. I am 80 and my “forgetter” works over time so I need the help. I live in South riding VA just outside od DC and I see you do a lot of lectures in this area so I would be interesting in coming to one of your lectures.

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  2. Jim – I remember reading that you’ve mapped over 90% of your segments to the contributing ancestors. I’m doing okay at the grandparent level, thanks to close relatives who have tested, but progress is slow after that since it is so difficult to triangulate with 5th-8th cousins. I would love to see a blog post on advanced techniques for finding MRCAs and solving segment matches with more distant cousins. Thanks,

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    • Rich, I think the secret is in contacting every Match in a TG; and trying to get them to communicate with each other. None of us knows all the answers – there’s a good chance that some of our Matches in a TG could find the CA among them, without my input – perhaps they’d come up with evidence on the other side of my brick walls and/or NPEs that I didn’t realize. We need to use the synergy of a TG team.

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  3. Jim,

    I am having trouble understanding a particular nomenclature in the TG Tree that GEDmatch built for me. I have searched through your explanations in this blog and have been unable to find an answer.

    In the boxes with the red outline I understand everything but the bottom line. An example is “3(0,1)>4(1,2).” Can you help me with this?

    Thanks,

    Jim Campbell

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    • Jim – please disregard those cryptic numbers in the bottom row. They were used by the programmer to help set up the graphic. They were used to place and link the boxes, and should have been removed before the utility went public.

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  4. Do you analyze GEDmatch results for a fee? If yes, what is the hourly rate? If no, can you recommend someone? I am trying to analyze my results to identify my great great grandfather. Y-DNA testing has not helped us. Three of us on GEDmatch are 2nd cousins (we are all women) and there are more cousins from different children of my great grandfather on GEDmatch. With three 2nd cousins, in theory shouldn’t it be easy to zero in on the common ancestor who is our great great grandfather? The problem is the analysis as I am finding it difficult to do.

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    • Maralaina,
      I am fully retired and devote most of my spare time to DNA and genealogy. One of my goals is to teach others how to analyze atDNA data. I have spent the last 6 years analyzing mine and am now working on my father’s atDNA. To do it all for a person takes a major time investment. I don’t charge for what I do, but I also don’t analyze other’s DNA. You might try http://www.ISOGG.org/wiki – click on the autosomal TAB and look for the list of resources. However, you are on the right track. Find all the shared segments (from your Match list), which also match (Triangulate) with your cousins from your great grandfather. In theory half of those Triangulated Groups will be on your great grandfather’s maternal side, half of them will be on his paternal side. Work with all of those Matches to see where they have a Common Ancestor. At this point it’s all about the genealogy – the DNA can only help so far.
      Jim

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    • Rebecca, Thanks for the link to your work. Just about everything you say in your post is the same thing I’ve been saying for years – and so I like your article and the direction you are emphasizing. Many good pieces of advice in your article.
      If you’ve read all of my blog posts, you’ll understand that I think Triangulation and Triangulated Groups (TGs) are just fine. In fact one could substitute TG for IBD in your Article. My TGs are the same as your IBDs, with all of the same rules as well as cautions (many of which I’ve similarly stated). There are two types of Triangulation: genetic (or segment) Triangulation (TGs formed from sufficiently overlapping shared segments from widely space cousins – this is a purely mechanical process and does not require genealogy); and genealogy (or ancestor) Triangulation (getting at least 3 widely spaced cousins to agree on the Common Ancestor (CA) – and in the end getting most of the Matches in a TG to agree on the same CA line). Since TGs have to be on either a maternal or paternal chromosome, some genealogy is required to assign them to the proper side. Triangulation does not lead to errors, it leads to rock solid chromosome mapping. Any process (including “solving IBDs”), if done incorrectly can lead to errors. I’ve been a very active genealogist since 1974 – and an active genetic genealogist since 2002. My atDNA spreadsheet now has 259 TGs with CAs, 102 TGs w/o a CA, and 55 “fabricated” TGs in the gaps to “fill up” all 45 of my chromosomes. I have many TGs with multiple CAs identified with the Matches; but only one ancestral line is linked to each TG – that is one of my ancestors, at each generation, going back to the “founder” of the TG. There is, in fact, a single ancestor who started each full TG. Ancestral to that, the TG does not exist intact, it was different, smaller segments from different ancestral lines. Some of our Matches, with smaller shared segments can, however, descend from more distant ancestors of that CA (but not with the full TG segment) – this leads to a subset TG with it’s own, more distant, CA. Our TG Matches can also have MRCAs with us all along our own ancestral path. This is why “walking the ancestor back” is an important method to “solving” a TG (along with genealogy Triangulation). With all of the new Matches that are now (2017) pouring in, we should be getting cousins at all levels in our TGs.
      Thanks again for your comprehensive article that applies equally to solving IBDs/TGs.

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