Fun thread, thanks for posting On my Dad's Norwegian side: My largest TG is 40 people on chr 9 from 80 to 87/90 for me and my Dad which appears to be ancient DNA of some sort, mainly Russian matches, some Polish, some Danish, a few AJ. No possibility of finding a common ancestor that I can see. Then I have a TG of 30 people, for my brother and Dad, clearly on my WOLD line from the Drammen area, from 45 to 55/67 chr 2, MRCA not yet found and another TG of 20+ of Finnish DNA on chr 10 from 37/44 to 53/54 for Dad and my brother unlikely to find over on my maternal Ashkenazi side there are more pileups than I can list! Kitty --------------------------------------------------------------- Kitty Munson Cooper, web developer,programmer, San Diego,CA genetic genealogy blog at http://blog.kittycooper.com/ family history and genealogy at http://kittymunson.com On Sun, Dec 13, 2015 at 11:35 AM, B Griffiths via < genealogy-dna@rootsweb.com> wrote: > Hello Andreas > > > What is the largest number of matches that you have in your triangulated > > groups? > > My largest group is 67 people matching me (and my mother) on > chromosome 8 within the area between 109000000 - 128000000. > > I would have done some cross checking when each of them initially > shared with me and most of them I have marked as cross matching, > although not everyone matches everyone else. I have just rechecked > two of them - one matches 62 of the group (this person matches me from > 109000000 - 126000000, 16.8cM), the other 50 (they match me from > 117000000 - 125000000, 10cM). > > Even the person with the smallest match to me in this area > (118000000-123000000, 5.3cM) matches 34 of the others, his longest > match to any of them being 15.5cM, over a segment 103000000 - > 123000000. > > I wish it were true that the large groups of 'people can "crowdsource" > together and identify the CA much quicker than a group of 3 can ' . > That had been my hope but, in most of my larger TGs, the majority of > the people match each other over just one segment and so all seem to > be equally distant from each other. Whereas the first match I had, > where we identified a common ancestor, was actually the only match on > that segment. I suspect (as I am in the UK), that the larger TGs are > where a distant ancestor emigrated (usually to the US) so long ago > that they now have many descendants, who just happen to be DNA tested. > > As to whether such groups class as "pile ups", I don't know - but if > you start discounting them as being too distant, what's the point of > triangulation? Where is the boundary between a "relevant" TG and a > "population based" TG? > > My working principle, for now, is that if people in the group cross > match, then the group is genuine/relevant. > Best wishes > Barbara Griffiths > > > > > > On 13 December 2015 at 10:56, Andreas West via > <genealogy-dna@rootsweb.com> wrote: > > Hi everyone, > > > > I hope we can find some consensus here and maybe some of you know even > what > > number (of matches at a certain loci) is used by AncestryDNA to identify > > pileups. > > > > We're obviously not talking about 1000 here as that would give us 499500 > > 1-to-1 comparisons to run between the 1000 matches. That's the main > reason why > > DTC DNA testing companies (and also GEDmatch) are interested to identify > > pileups to limit useless calculations (which in the end will still not > find a > > single triangulated group (maybe) or it's too far back anyway, see the > Timber > > algorithm used by AncestrDNA to cut matches. > > > > a) I have 97 matches (at the same loci) for one of my kits (at the "X" > > chromosome interestingly, it's a female person), which means 4656 > > combinations. Is that number already a pileup? > > > > How about: > > > > b) 52 matches = 1326 combinations > > > > c) 36 matches = 630 combinations > > > > d) 23 matches = 253 combinations > > > > e) 18 matches = 153 combinations > > > > Where is the line to draw? At a, b, c, d, e or where? > > > > > > What is the largest number of matches that you have in your triangulated > > groups? > > > > We obviously don't want to miss out a large TG as it also means a lot of > > people can "crowdsource" together and identify the CA much quicker than a > > group of 3 can (usually means also more family trees to compare with). > > > > Thanks for your answers! > > > > Andreas (WEST) born BASSO > > > > My ancestors: [http://www.wikitree.com/genealogy/Basso-Family- > > Tree-23](http://www.wikitree.com/genealogy/Basso-Family-Tree-23) > > > > ------------------------------- > > To unsubscribe from the list, please send an email to > GENEALOGY-DNA-request@rootsweb.com with the word 'unsubscribe' without > the quotes in the subject and the body of the message > > ------------------------------- > To unsubscribe from the list, please send an email to > GENEALOGY-DNA-request@rootsweb.com with the word 'unsubscribe' without > the quotes in the subject and the body of the message >