Tweet
I was feeling quite chipper at getting close to identifying my paternal bloodline after getting results at a genetic distance 3 to four people who shared the same surname as each other but from ostensibly two different families. That, however has diminished, when I discovered another family of the same name and county who, though connected by marriage on my maternal line, were not blood related. The reason I was perturbed was that two brothers who have taken the test have a GD3 from each other and one has a GD2 from his uncle and a the other a GD5. On that basis what, if anything can be ascertained from genetic distance? Incidentally, they have also taken Big Y tests.
-
-
With yDNA, you need to look more at GD-0 to GD-1 because the further away your GD is, the further back your shared ancestors are. My GD-1 matches share ancestors from the mid 1700's. This shared ancestor is 7 generations back for me. GD-2&3&4 you would have to be able to trace ancestry much further back. How far back can you trace your paternal line? That will determine what GD matches you can even look at. -
I cannot trace my paternal line. My point is if a GD of 3 can occur between brothers and a GD of 5 from a nephew to an uncle (that's at 111) what is GD telling us at all that is useful to genealogists, especially for those like myself who are trying to find out their ancestry? This example is of known close relatives yet they differ so much, so where does that leave folk of the same surname who are say, GD2 to these folk? What can they make of it
Obviously the mutating markers may be different ones but unless FTDNA are going to let you know which markers are different that's not much help. In my experience many people do not respond to e-mails and do not publish their results, so knowing just the GD , as above, is pretty useless anyway even without discovering close relatives can have such a wide variance.Comment
-
Use FTDNATiP (click in the TiP icon) to get estimates.
Genetic Distance by itself is not that informative. For example, it could be distance of two (2) between a father and his son.
W. (Mr.)Comment
-
Can you afford Big Y?Comment
-
Thanks. Yes I have just done Big Y but of course there are fewer people for comparison.
Exactly my point - Genetic Distance is not very informative. But Big Y is sold as a means of finding deep ancestry rather than relatively recent ancestors. I know my father was my father and that's about as far as it goes.
I also think it is unlikely to be coincidence that of my five matches four have the same common surname traceable in both cases to the 1750s in the same English county where most of my ancestry originates, (three are most certainly related to each other, one is a "Not Known" like me and the other a separate family so far). My GD is 3 to all, effectively. The two family groups are a GD 4 from each other. The other NK a GD 2 to one family group but 4 to the other.Comment
-
You had mentioned that these matches also had Big Y test. And? Do you see them as matches in Big Y? Yes/no? If yes, I would have two questionsOriginally posted by Doublemartini View Post
Mr. W.Comment
-
Sorry, I think I have confused you, Mr. W.
I do not know my paternal bloodline. My Y-DNA results gave me hope, in that I found 5 people who matched to varying degrees and of that 5, 4 shared the same, common, surname but paper trail-wise they are ostensibly from two different families. Three are known to be related, one is "Not Known" like me, the other is from a different family with the same surname. All are from the same county.
My point is that this suggested that this surname may be mine too, and so warranted more investigation so I felt on the right track.
Meanwhile, I contacted two brothers with the same surname originating in a different part of the same county who have done the Big Y as well as Y-DNA tests. The result is that we are not closely related at all through Y -DNA, but because the results between two brothers show a GD 2, but GDs of 5 and 2 respectively between them and their uncle, I am questioning the usefulness of GDs as a measure of anything, especially if we do not have automatic access to those actual marker differences through FTDNA, and cannot access them if respondents don't reply. The brothers and uncle did the Big Y and confirm the brothers are full brothers.
My point is that to me this illustrates not only that mutations are only any sort of a guide if you can discover at what point the mutation first occurred (but in most genealogical time frames this is probably outside of the written record), or that mutations can happen so fast and/or so frequently a pattern cannot be discerned, thus a GD and TIP are almost meaningless.
The odds against discovering exact or truly close matches at current numbers testing must be extremely high, especially so if you have no surname to go on.Comment
-
Yes, I am confused .
I think a difficulty in using DNA matching for finding relatives is that in Real Life™ someone is either related or not. DNA matching only gives probabilities.
My examples... I happen to know my 4th cousin (Big Y and Family Finder results confirm it - not only results of us two!). At 67 markers, his GD to me is 3. At 12 generations, FTDNATiP gives us 10% probability that we are from different lines...
On the other hand, an individual with the same surname as mine has GD=24 to me (again 67 markers). At 18 generations, FTDNATiP gives us 0.10% probability that we are related. Big Y results made it more definite, as by YFull estimates time to our Most Recent Common Ancestor is more than 4000 years.
If money were not coming into play, it would be better to have a Big Y test, and some Y DNA STR test if required/desired.
W.Comment
Comment