Next Thursday, July 16, I will give my presentation on using triangulation with autosomal DNA test results over in Carlsbad for DIG, the DNA Interest Group of the North San Diego County Genealogical Society (click here for the where and when). This was last given at the Jamboree and might be given at the next Rootstech.
I like to use examples from my own research in my talks to illustrate the “how tos.” My blog post on triangulation from earlier this year does just that, specifically discussing the case of a possible third cousin once removed, postulated from the paper trail, and then proven with DNA triangulation. Other cases discussed include unknown DNA relatives matching at the same spots.
To quote my own talk notes…
“In genealogical research we talk about the genealogical proof standard; in DNA explorations we talk about triangulation. Triangulation of autosomal DNA tests results is when three people all match each other at the same DNA location.
To quote the ISOGG wiki (which I recommend you look at for understanding DNA terminology): ‘If you have at least three people with a common ancestor matching on the same segment then you can infer that the segment came from that ancestor.’
Or to rephrase that, if three people all match each other on the same segment then you can infer that they have a common ancestor.”
Hope to see some of you next week!