Mary ICW shows people who share DNA segments, but it doesn't tell you which segment they match on. If you match A and B on the same segment, most of the time, when they are ICW each other (you already know they are ICW with you on a particular segment), their shared segment will be on the same segment and you'll have Triangulation on that segment. But sometimes they don't match each other on the same segment you match them - and then there is no Common Ancestor. When you have say 20 matches on a segment (not hard if you test at all 3 companies and use GEDmatch) - and they are all IBD segments - they should sort into two Triangulated Groups - one on each of your patent's chromosome. These two larger segments - one from each Common Ancestor - are usually offset from each other. And each Group can band together as a research team to find their Common Ancestor - everyone in the Group benefits. But if you have some of them in the same group who don't really match each other on that s! egment, their input to the group's research will really point in the wrong direction - wasting a lot of time and effort. So it always pays to verify that those who should match each other in a Triangulation Group, really do. Jim - Sent from my iPhone - FaceTime! On Oct 7, 2013, at 9:51 PM, Mary E Hall <just23gen@gmail.com> wrote: > I'd like to hear more on our concerns. > > Actually, I was somewhat "surprised" that when I started playing around > with "In Common With" and chromosome browser together this weekend, I > saw amazing clusters of matches along one segment of DNA. > > I had enough info on some of the paperwork pedigrees that it seemed either > "too good to be true", an amazing coincidence, or something very strange. > > I co-lead our local genealogical DNA special interest group, mostly due to > my interest in DNA and because I believe it holds great future. But I also > temper my "enthusiasm" so that people have realistic expectations and spend > their money wisely. And I try to be honest in my assessment of the > various companies strengths and weaknesses. > > I'm not sure what to make of the new Triangulation/Chromosome matching > feature of FT DNA. > > So, am interested in others opinions, too. > > Mary