Integrating With Genealogy

ProTools is a powerful tool. But it has it’s limits. 1C and closer relationships are very accurate, in my experience. Beyond that, the range of possibilities grows quickly as the cMs fall below the 1C range. But think about what that means… A 1C relationship takes us back to our grandparent level. Think of a 20 year old genealogist with a 50 year old parent, and 80 year old grandparents. Those grandparents would be in the 1950 census. And the census is a pretty good tool back to 1850 – another few generations. You might argue that the census is not rock solid in every case. There may be adoptions, NPEs, etc. That is true, but those individuals will not show up as DNA Matches – for the most part.

Yes, there are still a few situations that may slip through. But on the plus side, the census and ProTools will sort out a high percentage of false relationships, and/or incorrect genealogy “research”.

Used together, the census and ProTools can pretty accurately cover the past 175 years.

[22DE] Segment-ology: ProTools 23 – Integrating With Genealogy by Jim Bartlett 20250131

A Rant about Relationships

I praise Ancestry for ProTools – just about everything about it is great. I have often reported how accurate the close Relationship Estimates are. I rely almost 100% on 1C and closer relationships; and have found many 2C relationships to be correct. I worked for several days on a 3C relationship – knowing the Trees of the two Matches pretty well – to no avail. This is becoming a regular occurrence.

I’ve noted over the past year, Ancestry has tightened up their Relationship Estimates – all are now within 4C. We can tag a Match at 4C or closer, or Distant. A far cry from the Circles where Ancestry showed us how we were related out to 8C; or even the current ThruLines out to 6C.  Will they change again, tomorrow, to only showing Matches related within 4C or closer? I am long since past that threshold…

So I decided to take a deeper dive, under their hood, to see what they predicted for small cM Matches. I randomly selected a 6cM Match that I had saved. She was predicted to be Half 3C1R or 4C – evidently their deepest estimate. So I clicked on that estimate to get their more in depth analysis. Here are two screenshots of their analysis [sarcasm: based on results from their 27 million testers?]:

It seems to me they have adopted the “Cinderella Principle” – push hard to fit the data into a desired result. Are they really claiming that 99% of all Matches at the 6cM level are a 4C or closer? The Ancestry folks are much smarter than that…  They know better, and, for some reason, AncestryDNA is distorting the truth! SHAME! Our tens of thousands of small cM Matches do not fit into a size 4C Cinderella slipper!!

Bottom lines: still rely on 1C or closer relationships for analysis with ProTools; IMO, beyond 2C, treat the estimates as garbage; let me/us know if you have some insight that I’m missing (other than something related to greed).

[22DD] Segment-ology: ProTools 22 – A Rant About Relationships by Jim Bartlett 20250119

Adding a GUESS

Setup

gk (Match1) is known 5C1R – with grandmother: Anetta b 1926 m SURNAME1 > father: private Male > gk; AND gk has 10 known 2C to Anetta’s father (in the line going back to our MRCA).

Justin (Match2) shares 898cM (estimated 1C) to gk; and has a very small Tree of Private Ancestors.

Analysis

To be a 1C to gk, Justin would need to share grandparents with gk – either gk’s paternal grandparents or gk’s maternal grandparents. From the setup (above), we know the maternal grandparents are SURNAME1 and Anetta b 1926; we don’t know (but can often find) gk’s paternal grandparents. In this case there wasn’t enough info in Justin’s Tree to help.

However, there is another way to determine which set of grandparents Justin descends from. If he descends from Anetta’s side, Justin would also be 2C to the 10 known 2C that gk has (NB: all 2C match each other). If Justin descends from the other grandparents of gk, it is highly likely that Justin will NOT share any of the 10 known 2C to gk.  A quick look at Justin’s Shared Match list, shows he matches ALL of the same 2C that gk has. Justin is clearly a 1C to gk on gk’s maternal side – which is the side back to the MRCA with me!

Therefore, I am very confident in adding Justin to my Tree with UNKOWN parent and KNOWN grandparents: SURNAME1 and Anetta b 1926. The rest of the path gk has back to our MRCA is already in my Tree.

This places another Match into my Common Ancestor spreadsheet and into my Tree. It takes this Match off the list of unknown (aka Mystery) Matches. In Shared Match lists, Justin will now show up as a known (Dotted) Match – reinforcing Clusters. I don’t know if Justin’s addition to my Tree will help AncestryDNA with future ThruLines evaluations, but I hope so. I *know* it will help me.

A similar analysis can be made for a Pro Tools estimate of 1C1R or a 2C, but it gets less reliable with each additional degree of separation. There is also a higher degree of difficulty in the analysis, because the certainty of the cousinship estimate is not as assured and the number of possible alternatives that need to be addressed increases. It’s often not impossible, but it is harder. A strong factor is whether a *candidate* Match shares a lot of the same Shared Matches. In other words, if the candidate Match clusters with a lot of the same Shared Matches (which can be observed in the Shared Match list), to me that is a strong indication that candidate Match has the same MRCA. This needs to be tempered with endogamy or pedigree collapse – judgment is needed in those cases.

[22DC] Segment-ology: Pro Tools Part 21 – Adding a GUESS by Jim Bartlett 20250109

A Plan and some TIPS (corrected)

At the end of 2024, I wanted to review my Plan for using Pro Tools (and filing in a Common Ancestor Spreadsheet) and highlight some TIPS .

For the long haul – addressing all of your genealogy using Pro Tools – make a Plan! Perhaps a New Year’s Resolution…

I now think the best plan is to start with the closest Ancestors and work back a generation at a time.

That is, start with your grandparents –two grandparent couples [Ahnentafels 4 and 6]. The Matches at this level would nominally be 1C to you – maybe some “removed” – like a 1C1R or 1C2R – particularly as we get older:>( There are only two groups at this generation – one on the paternal side and one on the maternal side. So, two CA-Couple headers in the CA Spreadsheet. For each row under a header row, enter the Match information (name, cM, # segments, cousinship) and then the child of the CA and their birth year, and then the path to the Match.

TIP1: for each, and every, Match I list, I use Pro Tools to show *their* closest Matches – these are often close Shared Matches to them that can be figured out even if the SM has no Tree.

TIP2: for each Match I list, I add them (and their path to the CA) into my Tree (and apply the DNA-connection and/or DNA-Match Tags). I don’t know if the Tags help AncestryDNA build Trees or determine ThruLines; but it does help me when I run across them days/weeks/months/years later. Not necessarily a *certification*, but at least a reminder that I’ve reviewed the path before.

TIP3: Fill in some Notes for the Match – I always start with my CA code – example: #A0064P [the A means I’m satisfied the Ancestor is correct; and the # is a holdover from the days we searched for unique strings; the 0064P is Ahentafel 64 on my Paternal side [in a DNAGedcom Client Spreadsheet Report, I can sort on the Notes column, and they will group in order]

TIP4: I Star & MRCA Dot & Tagged-in-my-Spreadsheet Dot each Match – this unique Star-Dot-Dot “trio” clearly highlights Shared Matches who are already in my CA Spreadsheet. In a Shared Match list they help identify a Cluster.

TIP5: Each of the Matches under an MRCA Couple at this generation should match each other. They are 1C, 1C1R, 1C2R to you and each other, and all should Match. A Quality Control Check. [NB: I am tempted to add in any Aunt or Uncle Matches to my Spreadsheet; but they may be close to the Match, but not on the path to my Ancestor – when that happens they won’t have close cM ties to the other Matches.]

TIP5: I have a separate column in my CA Spreadsheet to indicate I’ve done all of the above. I’ve got about 8,000 Match rows in my spreadsheet and I’m reviewing each one to make sure I’ve covered all of the above and then check it off. As it turns out, some have changed their Trees, some have dropped out of Ancestry, Ancestry continues to update ThruLines, etc., etc. This checkoff indicates a fresh update.

Time now to tackle the four Great grandparent couples [Ahentafels 8, 10, 12, & 14].

Repeat the steps above for each of your Ancestor couples.

Note that TIP5 still applies – under each couple the Matches are 2C (or 2C1R, 2C2R, or maybe 1C1R) with you. These nominal 2C should all be close cousins to each other (sharing large amounts of cMs)

At any point in this process, take a break and chase down a rabbit hole or two. But then come back to this methodical process.

TIP6: Using this process, makes us treat all of our Ancestors equally. I tend toward favorite Ancestor lines, and this process forces me to grind through all of the Ancestors and Matches.  It’s a good thing.

A slight change occurs at the next generation [eight 2xG grandparent couples; 3C level; A 16 – A 30] At this level, TIP5 breaks down a little.

TIP7: Reminder – 2C-100%; 3C-90%; 4C-50%; 5C-15%; 6C-5% – (roughly)… This is the “curve” indicating how often true cousins will be a DNA Match to each other. ALL true 2C will be a DNA Match to each other. Of 10 true 3C, each one will usually have a DNA match with only about 9 of the others; but each of the 10 will have about 9 of the others matching – so these 10 would still form a pretty strong Cluster… Among a group of 4C, each one will only match about half of the total; and they may not all form one, strong/compact Cluster. And it gets worse, at the 5C and 6C levels… – some interconnecting cousin Matches, but not strong Clusters. However, now with Pro Tools we can find groups of strongly interconnected (closely related) Matches – strong ties to each other, but perhaps their strong subgroup is 5C to 8C with you.

At the 4C level, I see interconnected groups around the children of each grandparent couple; and sometimes a few interconnections between children. At the 5C level, as expected, I’m seeing groups (Clusters) form on the grandchildren.

Additonal TIPS

TIP8: multiple marriages; non-marriages: IF you and a Match only share DNA through one Ancestor, then your relationship is “Half”. Pro Tools often includes cMs for Half relationships, but these only apply with when you share only one Common Ancestor.

TIP9: Some Matches may be related to you multiple ways – give them a separate row (and Ahnentafel #) for each relationship. NB: If you are 3C on A16 and on A18 the odds are equal – with one segment, it could be either; with multiple segments, it could be both… However, if you are 3C on A16 and 4C on A38, with one segment, the odds are 4 to 1 that the DNA came from A16; and if you are 3C on A16 and 5C on A76, the odds are 16 to 1 that the DNA came from A16. This is because *shared DNA* is divided by 4 with each generation, on average. If you have shared DNA with a Match, it’s much more likely to be from the closest relationship.  

Please post in the comments if you have good TIPs that would help us all.

Happy New Year!

[I fixed the error in Tip 7, and reposted]

[22DB] Segment-ology: Pro Tools Part 20a – A Plan and some TIPS by Jim Bartlett 20250101