A ProTools Epiphany…
As I walk down my hitherto unknown Matches, I’m setting up a small spreadsheet for each group.
Important: Starting with a “base” Match, scroll through *all* the Share Matches – looking for those who share lots of shared cM with each other. Generally 90cM is a good threshold – these Shared Matches (with each other) would generally be 1C or 2C to each other. If I drop down to about 50cM, I get 3C & 4C too. Feedback from the LEEDS method indicates these over-90cM Matches tend to share the same grandparent. This can occur between two Matches who share much less cM with you. Your Matches may be fairly distant; but among themselves they are closely related. Often, some of these Matches are known to you – either through a good Tree or a ThruLines clue (with reference material). Looking through *all* of the Shared Matches, and then through *their* Shared Matches, I’ve usually found a group of Matches who are closely related to each other on some branch of my Tree.
Epiphany: At this point it is not critical, or even necessary, to “pin the tail on the donkey” precisely. These Matches may well be 3C or 4C or 5C or more to you, but they collectively anchor a sub-branch of your Tree. The fact that they share high-cMs with each other, is a very strong indication that their bond is strong and correct [classic genealogy triangulation]. And, even though they are more distantly related to you, their *grouping* is a strong indication that they are related to you through your Common Ancestor to that sub-branch.
Each of the Matches in this sub-branch (including those without Trees of their own), becomes a strong “tell-tale” that tracks a Shared Match Cluster and/or a Triangulated Segment of your DNA.
There is so much new ground to cover here, that I’m now shifting my focus. Instead of trying to fit each Match into a specific place in my Tree, with detailed genealogy research, I’m just highlighting the groups who are clearly descended from a specific person in my Tree. This specific person may be a child, or grandchild, or great grandchild of my Ancestor. At this point, it doesn’t add any more value to my Tree as a whole to know exactly how they relate to each other – just that they do closely relate to each other. Five or ten or twenty of my unknown Matches are now under a grandson of one of my specific Ancestors – although, they may all be around 5C to me. Other Matches cannot be in that sub-branch, unless they share an appropriate amount of DNA with others in that group. So, using inverse logic, we must find a different sub-branch for these other Matches
This process remains a hoot, and a game changer at Ancestry. I really think a large percentage of our Matches can now be correctly put into sub-branches of our Trees. This also highlights Match groups which will be helpful in getting through Brick Walls. Every IBD Match has to tie into some part of our Tree – ProTools is looking like a great tool to help place those Matches, and perhaps identify some small-cM false Matches. For me this clearly helps, identify small cM Matches who are related within a genealogy timeframe (as opposed to being very distantly related).
[22CK] Segment-ology: ProTools Part 2 TIDBIT; by Jim Bartlett 20240702
segment-ology 
Hello Jim,
Excellent blog!
I’ve found Pro Tools useful. Would be more useful with a chromosome browser on Ancestry.
I’ve searched your website as best I can and wonder if you can answer me this:
What constitutes a “long” segment? i.e. how many cMs is there in a long segment? 30? 60? 100? Does it vary from Chromosome to chromosome?
Where can I find this information?
I’m investigating the DNA of a lady born in the 1940’s who wants to know who her biological father is.
She has only 6 paternal DNA matches over 100cM, range 100-193cM.
On one side she has 2 matches over 100cM, 120 (commons ancestor 4 generations back) and 193cM (same ancestor 2 generations back). Next highest 58cM with no information
On the other side she has 4 matches at 100cm (no info) , 103cm (common ancestor 4 generations back), 123cm (same ancestor 4 generations back), and 176cM (same ancestor 5 generations back)
We don’t know which is the paternal grandmother/grandfather.
I have checked the descendants of the common ancestors and can find no relevant marriages.
Any advice?
Regards,
Jenny
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Jenny; Thanks for the encouragement. If you click on the Outline in the Segmentology header bar – it brings up a kind of Table of Contents that’s easy to review, and click on the link (I don’t have the recent posts in there yet).
There is no set/agreed definition of “long” segment. I tend to thing small-medium-large with the dividing points being about 20cM and 90cM. 90cM is recommended at LEEDS to get mainly 2C and closer; many think below 20cM is small. But, in the end, cousins are where you find them – at any cM. I don’t know of any difference among Chromosomes…
I was born in the 1940s – would like to help you – at my age, most of my Matches are once or twice removed… haha.
Start at the top of the paternal Matches and do two things
1. jot down the surnames of the Ancestors in their Tree (look for a Common Ancestor among the top Matches)
2. look down the Shared Match list for each one. Look for the Matches who share the most cM with each other (some may be in the 3500cM range, indicating a parent/child relationship; some may be siblings; some may be aunt/uncle/niece/nephew; some may be 1C or 2C – these are all important and help you to build *their* Trees. For those top Shared Matches look at the surnames in their Trees; and look at *their* Shared Match lists. It’s OK if you have to drop down below 100cM .
Try it some and let me know how it goes…
Jim
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Thanks for your reply. I guess that because chromosomes are different lengths and contain different numbers of genes then there must be a varying number of cM along each shared segment.
I had already built trees for each side, there are many, many family members but the trees are as complete as they can be, together with addresses and birth/marriage/death locations. The DNA between the matches confirms relationships between the matches now with Ancestry Pro Tools, as do most family trees and Thrulines, so I am confident that I have the common ancestors.
The problem, I think, is that the biological father was either:
born to a single woman whose partner was a descendant of the families, so he would not bear the names I have
or born within a marriage where the mother or father was a biological descendant of the families, but unaware of that and did not bear the names I have,
and had no siblings and no other children, hence the lack of closer matches.
Do you agree?
Regards,
Jenny
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Jenny – yes the Chromosomes are different lengths. We measure segments 3 ways: Base Pairs – how many of these molecules in the segment of DNA (and precisely where it is on the Chr); SNPs (the base pairs that are actually measured – about 600,000, or so, which sample the 3 billion base pairs from each parent); and cMs which is a measure of how likely the segment is – very roughly equal to the number of Mega Base Pairs (Mbp) – there is no conversion factor like we have from feet to meters. So a 20cM shared segment could be on any Chr; and the net result is we have lots more segments on Chr 1 than we have on Chr 20… The shared segment cMs don’t “shrink” on smaller Chrs – there are just fewer of them.
Each bio-Ancestor has exactly two bio-parents. So for a given bio-parent you’d have some DNA Matches to that bio-parent; all other things being equal, you’d also have some smaller segments (on average) to each of the bio-parent’s two bio-parents; and some more, smaller Matches to the 4 bio-grandparents; etc. It begins to peter out about the 7C to 8C level. “all other things being equal” doesn’t always work – recent immigrants usually have far few Matches (most tests are with Americans); also smaller than usual surviving children in a generation will reduce the descendant Matches.
In your case you want to find Matches to the bio-Ancestors going back – if one line draws a blank, it might be an NPE… Jim
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Sul chromosome 16 ho due triangolazione ognuno per fatti loro.adesso che ho testato mia madre e ha le non sono usciti allora quel chromosome per adesso e paterno.ho due triangolazioni ognuno per conto loro.ma alcuni matches del gruppo diciamo 1 hanno stessi numeri iniziele finali di alcuni dei mat hes del gruppo 2 ma ognuno triangola per I fatti loro.e sono tutti e due questi gruppi triangolati srparati sul chromosome 16 sono adiacenti ha un matches srmpre sul 16.che viol dire? Loro sono fra figli di cugini di 4 grado.
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Kevin – my translations of your posts are difficult to understand. But let me explain this: if you have two separate Triangulated Groups on Chr 16, you must treat them independently – they may be closely related or distant. You have your mother’s test – if either of these TGs also match your mother, they are on your mother’s side. If both do not match your mother, then both are on your father’s side. After that analysis, it is up to genealogy to tell you where they are from in your genealogy.
Are you looking, or hoping, that I can provide some other reply? If so, tell me what you’d like to hear, and I’ll let you know if I think that’s correct.
Jim
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Kevin.jim questi due gruppi ti ho parlato tante volte.ora non sono ha mia madre e solo ha me sarebbe paterno perche mia madre non corrisponde ha loro ricordi.e ha me cioe paterno che ho questi due triangolazione sul chr 16 ognumo triangola per fatti loro pero alcuni natch del gruppo sconosciuto che ti ho parlato tante volte hanno stessi inizio e finale con me ma anche con altro gruppo triangolato capito?ma quando li metto insieme non triangolano ognuno triangola per conto loro ma hanno stessi numeri iniziali finali capito grazie jim.
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Kevin.jim ho il test di mia madre ma come ho detto altra volta non sono usciti ha lei questi gruppi.adesso e rimasto quello mio e non ho il test di mio padre.queste due triangolazioni sono sul stesso chr 16 stessa posizione con numeri iniziali e finali del primo gruppo triangolato con me e con questo altro gruppo sempre sul 16 ma quando li metto insieme questi due gruppi triangolati separti poi non triangolano piu ognuno triangola per conto loro ma sempre sul chr 16 .
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Yes, I too am questioning –
do I make small changes to how I aggregate my information now that we have pro tools?
or, do I make wholesale changes?
Do I try and store everything in one place? (like a spreadsheet – or Ancestry Notes), or multiple places?
Where should my main tree be? On my personal computer only accessible by me? Or should it be on Ancestry? Or some other place?
How do I keep my tree up to date?
What information is too speculative to be public information?
What new tools will come up that will let me put in all this new information? And will it be able to tell me when something isn’t right about my tree statistically?
Overall, it’s opened so many avenues, and solves issues that were unsolvable before.. but it also innudates us with so much information we have to decide what information we actually need at our fingertips and which information we don’t need.
I don’t have these answers.. just a sense that I’m going to need to adapt to be the most optimized, and not exactly sure what that’s going to look like yet.
Cheers,
Brian
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Me, too!! Just realized my Spreadsheet was duplicating a lot of info already in my Common Ancestors spreadsheet AND the flood of new Matches needed to be added to the CA spreadsheet anyway – so I’m now shifting to my CA spreadsheet and adding columns for the * and shared cMs – this will save me some retyping and insure it’s all in one place in the end. But it sure gets complex. Starting from scratch I should have put together a relational database
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