Interpreting specific chromosome matches

[Family]

Hi, all!

I've looked at the chromosomal matches for 6 people who are thought to be matches on a specific family line to try to determine who the g-g-grandfather is for my mother, Betty.

Would anyone be willing to look at my attached 2 page pdf that shows the chromosomal matches and corresponding family lines to see if any conclusions can be gleaned?

Thanks so much!

Mary

[Canyon Wolf]

Interpreting specific chromosome matches

Despite the fact your C15 looks like it might triangulate, the size (less then 10cM, and especially because it is less than 500 SNPs) makes it highly questionable. I would not form any conclusions based on this match alone.

Your c10 matches look strong, but you need to take things a step further. It appears that Ron, Bob, David, Diane, and Betty may all share the same segment with each other. But you must make additional comparisons; Ron to Bob, Ron to David, Ron to Diane, Bob to David, Bob to Diane, and David to Diane, before you can be certain they all share this same match with each other - this is what we call triangulation.

Likewise with your C4,17,&20 matches - make sure Ron and Bob are matches to each other.

If they form good triangulated groups (all match with each other) than it is safe to spend time looking for the common ancestor that supplied the segments.

Always keep in mind that a person can match you multiple ways. For example; the match on c10 could come from a paternal line while the other matches could be on a maternal line.

Hope this helps