Tag Archives: Ancestry

ProTools Part 26

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Documenting a GUESS

Setup… A Match, with No Family Tree, is a 1C to a Known Match per ProTools. The Known Match is in my Tree with a specific line of descent from our MRCA; and a 1C estimate is very reliable. I want to put the new Match in my Tree and place them in my Common Ancestor spreadsheet – to “take care of” that Match by placing them almost certainly where they belong in my Tree.

As I’ve blogged before, there are only two options to place a 1C to a Known Match: 1. a grandchild of the Known Match’s paternal grandparents; or 2. a grandchild of the Known Match’s maternal grandparents. In other words, the new Match is a child of a sibling of the Known Match’s father or mother. A quick review of my Shared Match list with this new Match, clearly reveals the Match is on the same side (paternal or maternal) that I am on with the Known Match. In other words, I know the path from the Known Match back to our MRCA is through their father or mother. I can now see, through ProTools,  the new Match is related to me that way, too.

So I know the path from the MRCA down to the new Match – it’s the same path that I have with the Known Match down to, and including, the grandparent of the Known Match. What I don’t know is the name of the son or daughter of that grandparent = the parent of the new Match.

Up until recently, I’ve just named that son or daughter “block” as GUESS or Unknown in my Tree and in the “cell” of my spreadsheet. I’m now up to a dozen or so of these and can see many more on the horizon. My index of people in my Tree is filling up with GUESS and Unknown people…

I see four options for a name:

1. Continue with GUESS or Unknown [I usually reserve GUESS for iffy guesses]. I don’t like this – it’s not helpful to me or others reviewing my Tree – someday it may be very confusing.

2. Child of [name the grandparent]; ex: “Child of Bob JONES”

3. Parent of [the new Match]; ex: “Parent of Horatio Mitchell”

4. Sibling of [name the Known Match’s parent]; ex: “Sibling of Martha SMITH”

The Tree “box” and spreadsheet “cell” would have these entries and appear very close to other, known, boxes and cells. They would also be more specific in the Tree index, instead of a generic “GUESS” or “Unknown”.

I think I like (4) Sibling of Known Match’s parent the best because it specifically precludes the Known Match’s parent. In fact, I just did one new Match who was 1C to two different Matches so the description was: [sibling of John and Mary SURNAME] to rule them both out [after checking with ProTools].

I am interested in feedback on this topic – i.e. how to efficiently document Matches which clearly fit in a specific Tree branch. I am experimenting with 1C1R and even some 2C which clearly cannot fit anywhere else. Keyword here is “efficiently” – there is a LOT to do, and I don’t want to have to write a paragraph about each one. This is primarily for my own research. If I leave them as alive, no one else will see them; and if I mark them as deceased, the only people who will care will be close relatives to the new Match, and they may provide some feedback to me. I hope so…

[22DH] Segment-ology: ProTools 26 – Documenting a GUESS by Jim Bartlett 20250302

Segment Data for Ancestry Matches

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27

A Segment-ology TIDBIT

Genetic Genealogy has two main parts: genetic – the Shared DNA Segments; and genealogy – the Most Recent Common Ancestor (MRCA) with a Match. In a perfect world we link a Match and his/her Shared DNA Segment to the MRCA who passed it down to both of us.

Shared DNA Segments can be found for Matches at 23andMe, FamilyTreeDNA, MyHeritage and (by uploading our raw DNA data file) at GEDmatch. Unfortunately, none of those companies have nearly as many good Trees as Ancestry has. So finding MRCAs is hard.

Finding MRCAs is best done at AncestryDNA – many more people have tested there, and more of our Matches have good, in depth, Trees there. Unfortunately, AncestryDNA does not provide the precise Shared DNA Segment data that the other companies do.

The best outcome are Matches with MRCAs and Shared DNA Segments. I’ve run out of patience looking for MRCAs at FTDNA, MyHeritage, 23andMe and GEDmatch. Instead I am now looking for DNA segment data for my thousands of Matches at Ancestry with MRCAs.

This post will cover ways to get Segment data for AncestryDNA Matches – there are several:

1. Click on the Match name to bring up their profile – some have already uploaded to GEDmatch and list their Kit number in their profile.

2. Message the DNA Matches and request, suggest, cajole them to upload their raw DNA data to GEDmatch. I wrote a blogpost, here, about doing this. I’ve messaged many Matches requesting that they upload to GEDmatch. A few have…  The best results occur when I include my email address and promise to report back my findings and to help them with autosomal DNA.

3. Ask the DNA Match if they have tested at one of the other companies, and what is their user name there. Some have…  I’ve tested at all the companies and can usually find them.

4. Try to find the Ancestry user name at GEDmatch or vice versa. It sometimes works.

However, in looking at my GEDmatch One-to-Many list, I see many more Ancestry kits, that I have not yet linked to Ancestry names. Many folks use use very different names.

NB: Large segments (say over 30cM) will usually be about the same cM at AncestryDNA and the testing companies/GEDmatch. However, many segments below 30cM have been “Timbered”, and Ancestry then reports a smaller segment than the other companies report. You can always click on the “segment” line on their Match page and see what the “unweighted” cM value is – this is usually fairly comparable to what you see at GEDmatch. It’s a good idea to check this when there is an apparent discrepancy.

A better way – a Segment-ology TIDBIT

1. At GEDmatch Tier 1, run the One-to-Many list. When I set the limit to 1,000 Matches, the smallest Match shares 22.6cM – a good place to start.  NB: By default, this list is sorted with the Matches with the most shared DNA at the top.

2. Sort the list on the Source column (it has the source of the DNA test data)

3. Scroll down the list to the beginning of the Ancestry kits. NB: these Ancestry Matches are still listed with the largest total cM at the top.

4. Work down this Ancestry list one by one, trying to find the Match at Ancestry. The closest ones at the top of the GEDmatch One-to-Many list are usually the easiest to find near the top of your AncestryDNA list of DNA Matches. Usually the largest Matches (most cM) will have the same total Shared DNA cM at GEDmatch and AncestryDNA – so even if the names are different, it’s often easy to find the right one at AncestryDNA.

5. As you go down the list, the AncestryDNA cM total tends to be smaller than the GEDmatch total, due to the Timber down-weighting. NB: you can always click on a Match’s AncestryDNA cM total to see what the unweighted total would be – it is usually pretty close to the GEDmatch total.

6. By working down both lists (the GEDmatch list and the Ancestry list), I’ve found they are roughly in the same order. And, through a combination of cM amount, user names and email addresses, I’ve been able to find most of the top GEDmatch Matches at Ancestry. If there is some doubt, I’ll look at the Shared Matches at Ancestry to see if any grouping would provide a clue. UPDATE: GEDmatch info puts the Match in a TG – look in that TG for other Ancestry Matches, then search Ancestry for one of those Matches and scroll down their Shared Matches for a likely link (this is generally a somewhat shorter list).

So far I’ve been able to link over 90% of my top GEDmatch kits with my Ancestry Matches. It’s easy to determine the TG at GEDmatch, and I put the TG ID in the Match Notes. Even if I cannot determine an MRCA with the Match at Ancestry, the Notes are invaluable in the Shared Match lists – they clearly form Clusters in most cases.

In just a few hours, I’ve been able to link over 100 Ancestry Matches to TGs. It will get harder as the segments get smaller and more scrolling is necessary at Ancestry to find a “fit”. But this process is worth the work, IMO, as it adds TGs to Matches at Ancestry. It adds evidence about the true ancestral line for each TG.

[22BH] Segment-ology: Segment Data for Ancestry Matches TIDBIT by Jim Bartlett 20220706