Eric There is a trade-off involved, and *optimal* depends on your objectives. A first cousin generally has more cM and segments, but can only point to 2 grandparents (depth into ancestry is less); a second cousin doesn't have as many cM or segments, but does point to the specific grandparent and his/her parents (so depth is greater). I personally think the best strategy is coverage. That is some cousin for each grandparent; and when that is satisfied, you have to decide if additional cousins are needed to do the most for each grandparent, OR go to more distant cousins for each great grandparent. I believe if you test at all 3 companies and use GEDmatch, you'll get 1-2 thousand Matches with Colonial ancestry. This is sufficient to randomly cover 90 percent (my estimate) of all your chromosomes. As you pay for 3rd cousins and beyond, the number who will match you drops off quickly. They are still helpful in proving the biology of that ancestral line (they will match others in the line), even though they don't have a matching segment with you. I guess the bottom line, IMO, is that *optimal* strategy changes as you go along. You need to reevaluate after each test is posted, when you see what the results actually are. Jim - Sent from my iPhone - FaceTime! On Oct 8, 2013, at 11:19 AM, "Eric S Johnson" <crates@oneotaslopes.org> wrote: > Jim, Elizabeth--I hear you (and understand why: 50%, 25%, etc.) about how > the strategy I've proposed will have potential holes in it. > > But the original question (in which I'm very interested, too) was about the > *optimal* strategy to choose "who to test next," not "how to have a set of > tests which are collectively perfect." > > If I've tested myself, and my two parents (and none of my grandparents are > alive), and I only have enough resources to test one more person, wouldn't > it be smartest to spend that a parent's cousin ... etc. (up through the > chain I described). > If I have lots of resources, then the time will come when my > strategy's exhausted itself (because I won't have enough information to find > person number 11), and *at that point* the highest marginal value for "the > next test" would come from another cousin of one of my parents, etc. ... ? > > I'm not at all sure of myself--just trying to apply my own primitive logic > to the question. > > Best, > Eric > OpenPGP: 0x1AF7E6F2 ● Skype: oneota ● XMPP/OTR: berekum@jabber.ccc.de ● > Silent Circle: +1 312 614-0159 > >> -----Original Message----- >> From: autosomal-dna-bounces@rootsweb.com [mailto:autosomal-dna- >> bounces@rootsweb.com] On Behalf Of Jim Bartlett >> Sent: Tuesday, October 8, 2013 21.57 >> To: autosomal-dna@rootsweb.com >> Subject: Re: [AUTOSOMAL-DNA] Matches with a common surname >> >> Eric >> >> This process is a good one, but it won't cover all your Matches at each >> generation. >> >> At the parent generation, your Matches fall into 4 categories: Parent 1, >> Parent 2 either Parent 1 or 2 (when the parents are related) and IBS (not >> from either parent) - these latter two you recognized in your post. >> Aunts/uncles will help some here, if you can't test a parent.