Shared Segment Spreadsheet Incarnations

For me, the Shared Segment Spreadsheet is a critical tool, which evolves through four incarnations.

1. It starts as a collection of all your shared DNA segments – from each company. This also means a collection of all your Matches (except AncestryDNA), some with multiple shared segments. It can be searched and sorted.

2. Use as a segment Triangulation tool. Sort on: Company + Chromosome + Segment Start to arrange all the shared segments (within a company) into Chromosomes. And within a Chromosome they are arranged so that overlapping segments are close to each other.  With this “view” each segment is Triangulated with other overlapping segments, or not. Maternal and Paternal Triangulated groups are formed*. Some of the under-15cM segments will not Triangulate and are labeled “false” and deleted or moved out of this spreadsheet –  “everybody’s got to be somewhere.”  This process is repeated for each company.

3. Form/identify Triangulated Group (TG) segments. Sort on: Side + Chromosome + Segment Start to separate the maternal and paternal segments and sort them in order within each chromosome. Since this spreadsheet is comparing all these shared segments with your own DNA segments, the shared segments from different companies will “break” into TG segments that align with your own segments. However, this phase of the process requires some judgment – the data is a little fuzzy and the ends of TGs will not be precise. You have to make a call. In general, to align with your DNA segments, each TG will end at the same Mbp as the next one starts. Make those calls and assign a TG Identification (TG ID)** for each segment. Make a TG segment header row for each one (I have 372 TG segments) that lock in the overall TG start and end positions and TG ID. TIP: make the TG header start location 0.01Mbp less than the first shared segment in the TG – so it sorts on top of the individual segments. Remember that every Match in a TG is related to you on your line back to a specific Common Ancestor (CA). Note: some small segments in a TG may go back further.

4. Use these TG groups to do the genealogy! Among the Matches, find the consensus path to the CA.

Summary: A shared segment spreadsheet has several uses – collection > Triangulation > TG ID > genealogy. The TG segment is your DNA segment. This covers all of your genetic genealogy, but you can always focus on one or more individual TGs, if you don’t want to eat the whole elephant at one time.

*I’ve covered the Triangulation process in other blogposts, and won’t repeat that here – this blogpost is about the three incarnations of the spreadsheet.

**I’ve covered TG IDs in other blogposts

[35BBa] Segment-ology: Shared Segment Spreadsheet Incarnations by Jim Bartlett 20251102

35 thoughts on “Shared Segment Spreadsheet Incarnations

  1. Uhm.se ho diciamo 17 corrispondenze con persone est europa e solo io sono unico italiano che vuol dire che ho antenati da quelle parti ho viceversa?il segmento triangolato e 7,1-9cM e loro mettiamo che sono tra rom 100%ho rom 50% e anche europei diciamo tu dici qualcuno anche se molto lontano proveniva da lì?

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    • Kevin, A Triangulated Group, is a segment of your DNA. A 7cM TG would represent about 0.1% of your DNA. If it was 100% Eastern European, then that would mean about 1 of your 1024 8XG grandparents was probably Eastern European… (or 2 of your 9XG grandparent couples) Jim

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      • Jim.na se queste correspodenze sono tra rom piene e mezze rom e anno pure Europa su 17 corrispondenzae io unico italiano che dici chi puoi essere la migrazione est Europa migrato verso sud Italia?e poi su 17 corrispondenze 9 anni oltre il segmento triangolato hanno un altro segmento uno per ciascuno su altri chromosomi che significa altri segmenti uno ciascuno che ho con loro su altri chromosomi oltre al segmento triangolato?

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      • Kevin, If you share more than one segment with these Matches, usually, they will all be from the same Common Ancestor, but that is not a requirement. In particular, a small segment could be from a different Ancestor further back. Technically we have to treat each shared segment individually to see what Ancestor they came from. I have several 3C Matches who share multiple segments with me, and all but one of the segments are from our 2xG grandparent couple, but the smallest segment is from an 7XG grandparent (I can tell by the surnames that the smaller segment is from a different line). Jim

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      • Si loro hanno tutti cognomi diciamo est Europa alcuni tipici dei rom.io ho cognome sud Italy non so come e possibile questa connessione che ti parlo sempre.

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      • Ciao.mia madre ha fatto test su mhyeritage e ha molte corrispondenze dna con triangolazione con molte persone albanesi che vivono in Europa le altre 4 corrispondenze italiane che corrispondono ha queste matches albanesi il segmento e 14cM che significa?

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      • Kevin, I don’t know for sure – but I’d guess that either your mother has some distant Albanian ancestor, or the Albanian matches have some distant Italian ancestor. Jim

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      • E se io ho molte corrispondenze con persone che da quel che ho visto hanno gruppi genetici dei rom e io sono unico italiano tu dici ho migrazione verso italia ho viceversa col segmento triangolato tra 7,1-ha volte cambia fino ha 9cM

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      • E su 17 corrispondenze che ho io una e sicuro mi a detto che i suoi genitori sono rom e poi ci sono altre 3 corrispondenze che dai loro cognomi penso che sono rom pieni e altre saranno meta e plausibile una connessione con quella popolazione?

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      • Ciao kit.su mhyeritage ho due corrispondenze che sul chromosoma 16 triangola No con più di 10 persone ma queste due corrispondenze sono allineati anche sul chromosoma 4 con una ha il segmento di 7,3cM e un altro ha il segmento di 6,7cM ma mhyeritage non segnala la triangolazione e pure hanno mai sono che significa?ho solo il mio test mia madre non corrisponde ha loro che significa che triangolato sul chromosoma16 e non lo fanno sul chromosoma 4?

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      • Kevin, It’s hard to say for sure with such small segments. MyHeritage has a different algorithm for Triangulation. If they say there is no Triangulation, then I would be suspicious that some of the small segments may be false – maybe even you own. Jim

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      • Che vuol dire alcuni piccoli segmenti possono essere falsi forse anche di mia proprietà?ma queste due corrispondenze sul chromosoma16 triangola No con più di 10 persone sempre con segmenti tra 7,1-9cM mentre sempre queste due che triangola No sul chromosoma16 sono pure allineati ambedue sul chromosoma 4 ma mhyeritage forse non segnala la triangolazione forse e vera triangolazione e solo che mhyeritage non la segnala?

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      • Si queste due corrispondenze triangola No sul chromosoma16 con un gruppo di 17 matches.il segmento varia ha volte e 9cM fino ha 7,1cM.e ha volte ho un gruppo tra 12-15+io ma sempre le 17 corrispondenze

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      • Kevin – it’s usual that kits with two shared segments will be from same Common Ancestor – BUT that is not a requirement. I’ve seen cases where there are different Common Ancestors – so be careful. If your mother Triangulates with the Matches, the CA is on her side; if you mother does not Triangulate with the Matches, then the CA is on your father’s side OR the segment group may be false (the smaller the segment, the more likely that it’s false). Jim

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      • Si ho una triangolazione sul chromosoma16 del segmento triangolato tra 7,1-9cM che significa molte generazioni?

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      • Kevin.il team di myheritage mi ha contattato per il discorso della mia triangolazione del segmento tra 7,1-8cM sul chromosome16 su myheritage con persone che tra loro sono tra rom e misti rom e loro hanno gruppi genetici dei rom ma io non li ho e loro mi hanno detto che anche se condivido una triangolazione co persone tra rom ho misti rom il mio profilo si allinea piy col il greco albanese cosa volevano dire?in effetti molti rom testate su myheritage hanno come etnia maggioritaria proprio il greco albanese

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      • Jim mi potresti spiegare che vogliono dire il team di myheritage per la mia triangolazione con segmento tra 7,1-9cM sul chromosome16 con persone misti rom?.tu mando i messaggi potresti spiegarmi cosa vogliono dire?

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      • Kevin
        Each of the companies, including MyHeritage, analyze all of the DNA they have collected along with the Trees – their goal is to determine pieces of DNA that came from different geographies. Then they compare your DNA, specifically, to see which geographies are in your DNA result – by percentage. It’s a rough estimate, and each company has a different method. Although most of the companies will agree, roughly, with the continent estimates, they can vary a lot on the smaller geographical areas. It means that MyHeritage estimates part of your DNA came from Albania Greece – it means they think some of your Ancestors came from that region. Jim

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      • Si ho in effetti greco albanese etnia essendo su puglia ma il mio collegamento con le corrispondenze miste rom rom che potrebbe significare?buon anno.

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      • Kevin.ho ricevuto un altra corrispondenza DNA di 13,9cM con due segmenti uno triangolato il piu grande di 7,1cM sempre sul chromosome16 e si e a aggiunto ha quel gruppo di 18 match che triangolano e corrispondono sul chromosome16 e anche questa corrispondenza ha genitori popolazione rom ungheria.il team myheritage mi ha detto che e una connessione distante e mi ha detto non significa che tu sia necessariamente rom ho che tu abbia una significativa ascendenza rom che vuol dire?

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      • Kevin: I don’t know… It may mean what I’ve been saying: it’s a very distant Match, and it could come from anywhere… IMO, it not possible to be precise with such small/distant segments. However, you seem to be building a large Triangulated Group of Matches who all point in the same direction. Why not just accept that as a strong clue? Jim

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    • Suzanne, Yes! I sometimes use DNA Painter for the visuals. But I use my Triangulation spreadsheet for analysis – for several reasons
      1. No one has exactly my segment from an Ancestor – but many have overlapping shared segments. It’s like painting a wall with a lot of brushstrokes to see the whole wall painted. With a spreadsheet I can determine the beginning and end of *my* DNA segment.
      2. For me, it’s easier to determine the end of a TG segment which should coinside with the be beginning of the next TG segments on a chromosome.
      3. I can easily sort and copy out the 372 TG segment summary rows that represent all of my DNA.
      For me, it’s beyond the picture. But Jonny has a lot of good tools like WATO which does analysis that I can’t do with my spreadsheet.
      Jim

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  2. Jim – When Ancestry Pro Tools came out, I thought it might provide the needed platform for them to finally provide a chromosome browser – and then the spreadsheets would REALLY blow up. But it seems they want to try to do the whole thing without segment data. It’s frustrating, but I’ve got to admit – I’m spending more time on Pro Tools and less on the other sites. Rich

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  3. Good advice Jim. I must say I started off with the spreadsheet but it became a bit too unwieldy for me given the size of the database. I started using the GDAT tool over 10 years ago, which allows you to do much the same thing. http://www.getgdat.com.

    Its functions follow your same theory but also allows for the inclusion of pedigree data which helps the analysis process.

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  4. Si io ho questo tg sul chromosoma16 che a volte anno stesso iniziò e fine quando faccio coppia io due di loro sempre su mhyeritage segmento tg tra 7,1-9cM.poiché so che non sono da parte materna perché ho fatto test mia madre mhyeritage e a lei non corrispondono e ho continuato dopo test mia madre che non corrisponde a avere altre corrispondenze che si aggiungono al tg già creato.

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