Hi Jim, I apply your method though I learned from both of you a lot ;-) This allows our web app to apply the same rule for everyone (important in coding). No information is lost, we do have the info from the closer cousins/parents who are indeed holding those smaller TG’s together. The chromosomes map which we build up automatically is key as it shows those close and far MRCA’s. I think there is still work to be done to try out which threshold is the best one for TG’s and when one should stop splitting them up further. Andreas > On 2 Oct 2017, at 01:16, Jim Bartlett <[email protected]> wrote: > > I did similar to Tim (after all, he taught me a lot). So after some time working out the biggest TGs and any other low hanging fruit, I spent 3 or 4 all nighters and went down through my spreadsheet as quickly as I could. I checked each segment against it's neighbors (up and down) in my spreadsheet, to see which ones they matched. Sometimes it was not clear, so I just skipped over those. The point was to make a full pass - beginning of Chr 1 to end of Chr 23 (X) - and group wherever I could. I tried to do several chromosomes at at time. This was in 2013 as I recall, when I had about 1/16 of the Match/segments compared to now. After that first pass, I had TGs that covered about 2/3 of my DNA. I then made another full pass, and fit some more segments into existing TGs and formed a few new ones. And by then I was taking IBC segments (didn't match either side) out of my spreadsheet. Over time, as more and more Match/segments came into my Match lists, the TGs grew a little and started touching each other and filling out large areas. Over these 4 years, the percent "coverage" has grown asymptotically toward 100%. If I were starting today, and had a program that formed the TGs, I could compress 4 years of work into a very short time - and get almost exactly the same result (and the computer wouldn't make the little mistakes I sometimes do). > > > Yes, I had several large TGs with close cousins in them with their large shared segments. If I ignore the large segment and look at the rest of the segments, it almost always naturally breaks down into smaller TGs. So I use the smaller TGs and include the close cousin's segment in each one. The close cousin creates a "knot-hole" and a "funnel" that shrinks the pool of possible Common Ancestors for the TG - see https://segmentology.org/2017/09/10/the-mrca-knothole/ The big TG has a closer MRCA, and the smaller, sub-TGs have more distant MRCAs which are ancestral to the close MRCA. Technically the TGs will continue to subdivide, but there is a limit to what we can "see", which imposed by the shared segment threshold we use. > > > Jim Bartlett > [email protected] > > > > > -----Original Message----- > From: Tim Janzen <[email protected]> > To: genealogy-dna <[email protected]> > Sent: Sun, Oct 1, 2017 2:15 pm > Subject: Re: [DNA] Difficulty understand Ancestry's shared matches > > Dear Andreas, > The way I handle this issue is to put everyone in a triangulated group who > shares at least a portion of the DNA segment that is the longest segment in > the triangulated group. The person in the triangulated group who has the > longest segment must not have a known relationship with any of my family > members. If this segment is say 30 cMs long there may be people in the > triangulated group who don't share a DNA segment with each other, but they > could share say 5-10 cMs with the person in the triangulated group who has > the longest segment on different portions of that segment. If I ever figure > out the genealogical relationship with the person in the triangulated group > who has the longest segment, then I can always break the triangulated group > down further into two or three triangulated groups. > Sincerely, > Tim Janzen > > -----Original Message----- > From: GENEALOGY-DNA [mailto:[email protected]] On Behalf Of > Andreas West > Sent: Sunday, October 1, 2017 10:20 AM > To: [email protected] > Subject: Re: [DNA] Difficulty understand Ancestry's shared matches > > > Btw, when you say 400 is that with splitting them into the smallest possible > groups? Many times we do see TG's where we have smaller TG's at each end > which are only connected by some DNA cousins who share the whole segment. > That would probably go above 400. > > > Andreas > > > > ------------------------------- > To unsubscribe from the list, please send an email to [email protected] with the word 'unsubscribe' without the quotes in the subject and the body of the message

Andreas, It would be great to have the threshold be a variable - the default at 10, 12 or 15cM, but the user could adjust it up or down. Jim Bartlett [email protected] -----Original Message----- From: Andreas West <[email protected]> To: genealogy-dna <[email protected]> Sent: Sun, Oct 1, 2017 11:56 pm Subject: Re: [DNA] Difficulty understand Ancestry's shared matches Hi Jim,I apply your method though I learned from both of you a lot ;-)This allows our web app to apply the same rule for everyone (important in coding). No information is lost, we do have the info from the closer cousins/parents who are indeed holding those smaller TG’s together.The chromosomes map which we build up automatically is key as it shows those close and far MRCA’s.I think there is still work to be done to try out which threshold is the best one for TG’s and when one should stop splitting them up further.Andreas

Unfortunately that won’t work Jim. Reason is that each user is part of many TG’s and having different threshold amongst your TG won’t work. Also we differentiate ourselves by making many difficult to understand decisions for the user. People don’t understand the thresholds in GEDmatch, it’s a tool for few but not for the masses. Andreas > On 2 Oct 2017, at 08:49, Jim Bartlett <[email protected]> wrote: > > Andreas, > > > It would be great to have the threshold be a variable - the default at 10, 12 or 15cM, but the user could adjust it up or down. > > > Jim Bartlett > [email protected] > > > > > -----Original Message----- > From: Andreas West <[email protected]> > To: genealogy-dna <[email protected]> > Sent: Sun, Oct 1, 2017 11:56 pm > Subject: Re: [DNA] Difficulty understand Ancestry's shared matches > > Hi Jim,I apply your method though I learned from both of you a lot ;-)This allows our web app to apply the same rule for everyone (important in coding). No information is lost, we do have the info from the closer cousins/parents who are indeed holding those smaller TG’s together.The chromosomes map which we build up automatically is key as it shows those close and far MRCA’s.I think there is still work to be done to try out which threshold is the best one for TG’s and when one should stop splitting them up further.Andreas > > ------------------------------- > To unsubscribe from the list, please send an email to [email protected] with the word 'unsubscribe' without the quotes in the subject and the body of the message