Circles vs. triangulation has been a hot topic for the past couple of days so I thought I’d throw in my two cents. I rarely use a chromosome browser to solve adoption cases. However, there are definite occasions when a hypothesis needs further investigation and at present, the chromosome browser is the best way we have to do that. Any other way would not meet the Genealogical Proof Standard.
We don’t know what we don’t know. If researchers are not using a chromosome browser, they are assuming that all shared DNA came from the common ancestors they think it does and in reality, that’s probably fairly uncommon. Most people have multiple connections yet to be discovered. Also, a circle is only as strong as the trees that build its foundation. For adoption and recent unknown parent work, building a perfect tree to original sources often won’t answer the necessary questions because it won’t link you to the proper individuals. Building a perfectly wrong tree (or as right as everyone else’s) will answer your questions because you have to fit into the puzzle. In this type of case, it’s irrelevant whether you share one or five sets of common ancestors because as long as you can find the one set that brings you back to the present, that’s really all that matters in order to find the solution. If all the people have incorrect trees (as people so commonly do when they copy them) then you will fit into their perfectly incorrect circle. How can you check it to an earlier generation to prove or disprove that circle? You’d have to whip out your handy-dandy chromosome browser because that’s the only proper methodology we’ve got to do that at this time.
It seems that Ancestry’s intention is to make it easy and appealing, which is great. More people who test means more matches for all of us. We must be cautious and realize that unsound conclusions create a tangled web of potential inaccuracies, just like trees on Ancestry, FamilySearch, and other family tree hosting sites. Those trees contain a plethora of good information but they need to be checked against original sources. Our equivalent of original sources is the chromosome browser. A lot of good and useful genealogical information is lost in the mix if shared segments are ignored.