Diana, How useful is it, do you think, to test up to 67? 2 members of our big group have done so, they matched 35/37 and are now 64/67. I feel it has really told them nothing. Certainly testing only 12 is useless, I matched 12/12 with 5 other Langleys but when we went further it was 17/25 and 20/37. I have tested up to 37 but have now persuaded one positive and one possible relation who I match 25/25 and 23/25 to go up to 37 to see if we can tie in the latter person. I am a seventh cousin of the former and had thought the latter descended from another brother, but he could branch out earlier I am hoping the 37 may tell us something or do you think we need to go to 67? Peter ----- Original Message ----- From: "Diana Gale Matthiesen" <[email protected]> To: <[email protected]> Sent: Thursday, July 24, 2008 8:48 PM Subject: Re: [Y-DNA-projects] Roll Call > My pleasure, Peter. And congratulations on the successes in your project. > I > think a lot of us were surprised at how many origins our surnames have. > If you > stop and think about it, though, part of what we are seeing has to be an > accumulation of NPEs. Some of those matches in other surnames may not be > coincidental, which is a good reason to test, minimally, 37 markers and, > preferably, 67. > > Diana > >> -----Original Message----- >> From: [email protected] On Behalf Of Peter Langley >> Sent: Thursday, July 24, 2008 3:20 PM >> To: [email protected] >> Subject: [Y-DNA-projects] Roll Call >> >> Hi, >> I am Peter Langley, a retired farm manager living in Ireland >> and have been doing genealogy for over 40 years now. >> I am also co-administrator of the Langley project. >> >> In the days before DNA testing I had rather naively thought >> that the majority of Langleys derived from the same source. >> Now with almost 50 members in the group we have discovered >> there are 14 unrelated families. >> >> I think we may have had some success >> So far only myself and two distant cousins know for certain >> where the Langley is in England that we originated from. >> However, one prolific group in the States, who could not get >> back to England, let alone work out how they are related have >> managed, by examining the origins of those who closely match >> them, to get an educated guess that it is Northumberland. >> >> Well done Diana for starting this list. >> >> Peter >> >> > > > > ------------------------------- > The topic of this list is Y-DNA *surname* projects. Discussion of > geographic, haplogroup, or mtDNA projects is off topic for this list. > ------------------------------- > 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 > >

It depends, in part on how common the haplotype is and in part on what you're trying to prove. As we all know, being R1b, especially being WAMH, can mean you have hundreds of meaningless matches at 12 markers and dozens at 25 markers. I've reached the point, for R1b, that I would not settle for less than 37 because I've seen a 23/25 match drop to 28/37. Conversely, I have a family whose haplotype is so rare, their nearest common ancestor is calculated to be over three to four thousand years ago. Even a 12/12 match with them is likely to mean a great deal. In fact, they have a value at one marker that is, so far, unique to them. I suppose we could get away with testing just that one marker, at least for the present. It also depends on what you want to achieve. Do you just want to support that you descend from your paper progenitor (i.e., that you belong to the correct family)? Or are you trying to prove *which line* you descend from him on? The more precise you want to be, the more markers you need to test. Remember that when you've made a DNA match in your surname, you have just proven that *two* improbable events have occurred simultaneously: that two strangers have the same name and the same DNA. That's one heck-of-a coincidence. I you couple that paper pedigrees that agree, you have slam dunk, take-it-to-the-bank support for a relationship. If you have just one of these events, that is, if you have the same DNA, but different surnames, you'll need a DNA match at a higher level to sustain the hypothesis of relationship. Conversely, if you have the same surname, but different DNA, you need a greater difference to falsify the hypothesis of relationship than if you had different surnames. In other words... If a SMITH and JONES match 34/37, I'm going to be less encouraged to think they're related than I might of two SMITHs match 32/37. And the solution for both cases is to upgrade to 67 markers. There are also reasons to "max out" your markers, beyond 67, but it's dinner time. I can't wait, but my cats can't. Diana > -----Original Message----- > From: [email protected] On Behalf Of Peter Langley > Sent: Thursday, July 24, 2008 5:10 PM > To: [email protected] > Subject: Re: [Y-DNA-projects] Roll Call > > Diana, > How useful is it, do you think, to test up to 67? > > 2 members of our big group have done so, they matched 35/37 > and are now > 64/67. I feel it has really told them nothing. > > Certainly testing only 12 is useless, I matched 12/12 with 5 > other Langleys > but when we went further it was 17/25 and 20/37. > > I have tested up to 37 but have now persuaded one positive > and one possible > relation who I match 25/25 and 23/25 to go up to 37 to see if > we can tie in > the latter person. I am a seventh cousin of the former and > had thought the > latter descended from another brother, but he could branch > out earlier I am > hoping the 37 may tell us something or do you think we need > to go to 67? > > Peter >

Peter, What the increased markers have done is to reduce the the time frame in which their most recent common ancestor likely lived. With the 35/37 match they were looking at a 95% chance that the common ancestor lived within about 26 generations (~650-780 yrs). The 64/67 matched reduced this to about 21 generations (~525-630 yrs). Knocking five generations (~125-150 yrs) off your time horizon may save a lot of time in the archives trying to establish the identity of that ancestor. If you know that common ancestor could not have lived with a certain number of generations you can use FTDNATiP (assuming they are FTDNA customers) to put a likely lower limint on when he lived. Going from 37 to 67 markers improves the time resolution on this lower limit as well. David Weston. See http://dna-project.clan-donald-usa.org/tmrca.htm for quick upper limit TMRCA calculations. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peter Langley Sent: July 24, 2008 6:10 PM To: [email protected] Subject: Re: [Y-DNA-projects] Roll Call Diana, How useful is it, do you think, to test up to 67? 2 members of our big group have done so, they matched 35/37 and are now 64/67. I feel it has really told them nothing. <snip> Peter