Initially a genealogist will generally focus on their closest Ancestors and relatives. But once those have been documented, it’s time to expand our goals and efforts to more distant Ancestors and cousins. Remember that even at close 3rd cousins (3C), roughly 10% of them will not be a DNA Match. They may share a little DNA, but below the threshold to be classified as a Match. This grows to about half of all true 4C; and most of the true 5C and beyond. The point is that the true 3C to 8C that we do find may well share only one small DNA segment with us. Don’t be afraid of that outcome – welcome it! As a long-time genealogist, every relative is important to me. Each one has the potential to have new information I’d like to see: records, pictures, stories…
I document my Matches with Common Ancestors in a Spreadsheet (see Chapter 7 in Segmentology Fundamentals). I now have roughly 10,000 such Matches from all the companies (heavily weighted at AncestryDNA due to ThruLines). I recently sorted that spreadsheet by shared cMs and made a graph.
The takeaway is that if you use 20cM or 15cM as your lowest threshold, you are ignoring a lot of your true cousins.
Don’t be a Small Segment Scaredy Cat! Maybe the small segment is false, maybe it’s true. So what? The prize is a new relative.
Originally drafted for Halloween, but I got distracted….
[06J] Segment-ology: Don’t Be a Small Segment Scaredy Cat! by Jim Bartlett 20261104
Ciao Jim si io delle corrispondenze dna su mhyeritage piccole ma triangolate e corrispondenze con piccolecM soglia 8cM e più fino a 23,3cM con un segmento due segmenti e uno con tre segmenti ho una triangolazione e alcuni di loro sono cugini tra primo e fino a terzo grado tra di loro la maggior parte sono rom e misti rom ma io non so come sono collegata poi queste piccoke corrispondenze abbiamo io e loro altre 18 corrispondenze condivise tutte sullo stesso segmento.
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