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measurement error in DNA testing?

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  • josh w.
    replied
    Originally posted by slwr View Post
    I don't totally agree or disagree with either of you, but having been doing genealogy for 25 yrs...and yes writing letters and swapping documents with others searching the same families by snail mail and having file drawers full of records, I don't agree that the paper trail of documents and pictures of our Ancestors will ever be of NO value...DNA is a good back up plan, but at this point its not an end all ,be all , I agree there is a LOT of Badly done genealogy on the Internet, a pet peeve of mine, is NOT carefully documenting every step back, I do have "Private"trees on Ancestry.com that way my kids & grandkids that live a distance away can access them , but I do see a lot of junk on there and when its my Ancestor & I know its wrong.. it makes me GRRRry
    I think the concern is that georgian1950 might be over-interpreting his dna results (seeing more than is there) to fit his understanding of family genealogical history. From georgian1950's comments, I think he understands the risk.

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  • T E Peterman
    replied
    As I see it, in the future, paper & DNA will work in tandem. The paper tells us which people to get tested. The DNA results tell us where to look for paper. Both should remain part of the record going forward.

    Timothy Peterman

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  • slwr
    replied
    Originally posted by georgian1950 View Post
    I'm in basic agreement with you. In my short time doing genealogical research, I've seen some crap out there, both from the time when family genealogists would write letters and exchange notes with others, mainly speculating about how things could be, and the more modern times when people play the video game called ancestry.com.

    I probably need to work more with the few matches I have with my surname, but everything I seen thus far supports the idea that the earliest the NPE could be is where I'm hypothesizing that it is.
    I don't totally agree or disagree with either of you, but having been doing genealogy for 25 yrs...and yes writing letters and swapping documents with others searching the same families by snail mail and having file drawers full of records, I don't agree that the paper trail of documents and pictures of our Ancestors will ever be of NO value...DNA is a good back up plan, but at this point its not an end all ,be all , I agree there is a LOT of Badly done genealogy on the Internet, a pet peeve of mine, is NOT carefully documenting every step back, I do have "Private"trees on Ancestry.com that way my kids & grandkids that live a distance away can access them , but I do see a lot of junk on there and when its my Ancestor & I know its wrong.. it makes me GRRRry

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  • thormalen
    replied
    Well as a big proponent of DNA testing I some what agree...but as an adopted person I feel that just because I am adopted, that makes me no less a Thormalen which is my adopted name. So the whole issue is not clear cut and is confusing when one is on the adopted side of things.

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  • georgian1950
    replied
    Originally posted by T E Peterman View Post
    Actually, I recommend re-building all established genealogies with what I call biological verification. All paper-trail proven patrilines should be triangulated, if possible. All connections to other sides of the family can be verified through Family Finder.

    There was a time when lineages mainly contained names; later people began adding birth, marriage, & death dates to lineages; then people began adding places & standards were developed for proper citation of a lineage.

    I can easily envision in say 2050, a genealogist disregarding a book thats loaded with documentation, because it is only based on a paper trail. People will be asking "where is the biological verification?" The time to start building that library is now.

    Timothy Peterman
    I'm in basic agreement with you. In my short time doing genealogical research, I've seen some crap out there, both from the time when family genealogists would write letters and exchange notes with others, mainly speculating about how things could be, and the more modern times when people play the video game called ancestry.com.

    I probably need to work more with the few matches I have with my surname, but everything I seen thus far supports the idea that the earliest the NPE could be is where I'm hypothesizing that it is.

    Leave a comment:


  • T E Peterman
    replied
    Actually, I recommend re-building all established genealogies with what I call biological verification. All paper-trail proven patrilines should be triangulated, if possible. All connections to other sides of the family can be verified through Family Finder.

    There was a time when lineages mainly contained names; later people began adding birth, marriage, & death dates to lineages; then people began adding places & standards were developed for proper citation of a lineage.

    I can easily envision in say 2050, a genealogist disregarding a book thats loaded with documentation, because it is only based on a paper trail. People will be asking "where is the biological verification?" The time to start building that library is now.

    Timothy Peterman

    Leave a comment:


  • georgian1950
    replied
    Originally posted by T E Peterman View Post
    I suggest that georgian1950 get other patrilineal relatives who are more closely related tested. Surely, his closest relatives will be I1. See how far back you can triangulate that. At the point when distant cousins begin getting R1b results, check your research really carefully. You may have inadvertently mixed paper trails with a different family. A lot of published lineages are simply wrong.

    I suggest you investigate this possibility first, before assuming that you have found an NPE.

    Timothy Peterman
    I appreciate your advice and concern, but I can assure you that the line back to my GGG-grandfather is solid. The line of the two brothers from the same county is a known Colonial line, not a fake genealogy that someone peddled a hundred years ago. What I need is a seventh cousin or greater to test to make sure that the line resumes its normal course after my suspected NPE. I don't know too many seventh cousins, but that is what I expected the surname DNA project would have helped out with. Maybe it's time to stage a coup d'etat in the project.

    Leave a comment:


  • T E Peterman
    replied
    I suggest that georgian1950 get other patrilineal relatives who are more closely related tested. Surely, his closest relatives will be I1. See how far back you can triangulate that. At the point when distant cousins begin getting R1b results, check your research really carefully. You may have inadvertently mixed paper trails with a different family. A lot of published lineages are simply wrong.

    I suggest you investigate this possibility first, before assuming that you have found an NPE.

    Timothy Peterman

    Leave a comment:


  • georgian1950
    replied
    Originally posted by josh w. View Post
    Good luck in your search. If I understand you correctly, only descendants of the disinherited son are I1 with all other relatives R1b1a2.
    Thank you very much. The search should be interesting.

    Just giving part of the story of how I arrived where I'm at seems to have been confusing to some people. Here are some more particulars. I have some fairly good records, mainly notes that a first cousin of my grandfather and some other close relatives made. However they were missing the link from my GGG-gf John, believed born about 1785 in North Carolina, to known lines of the surname that would carry the line back through Jamestown and to some characters that had a little involvement with English History. As the most likely path I had been focusing on two brothers with the surname that lived in one particular county in North Carolina. According to the family notes, one of the sons of John recalled spending time around that county growing up. Both of those brothers had their own John's with their known genealogy, so the link clearly was not them. I was thinking that the link was one of the other brothers to those two brothers, about whom not as much is known. That appears to be the case because my DNA sample matches up with a sample from a guy that is descended from one of those brothers. The dad of all of these brothers was the disinherited son that I talk about. If the NPE was further back than the disinherited son, many more members of the family would be coming up I1 instead of the expected R1b1a2. From a logical viewpoint, I'm pretty confident about when and where the NPE took place.

    Before I even had the DNA testing done, I attempted to map all of the descendents of John. While the effort is not 100 percent complete, I'm pretty familar with the surnames of cousins. It's interesting seeing all of the surnames that I didn't expect to pop up on the close matches. Some of these close matches are in places were the perpetrator of the NPE in my line could have done the same, or at least some of his immediate offspring exhibited similar behavior. I would say that people who behave like that tend to do it over and over again, giving me all kinds of cousins that I never dreamed of.

    As for help from the Project Adminsitrator of the surname project, it looks like we have one of those dormant ones.

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  • travers
    replied
    I'm confused too. You started out by saying you have a brick wall at your ggg grandfather and now you are saying after DNA testing he must be a disinherited son. So you don't have any paper records to prove your ancestor belongs to the family in question and DNA says he doesn't belong but how do you make the jump to him belonging to the family and there being an NPE? There could very well be no NPE at all you could just be looking at the wrong family. Not every family with the same surname will be related, all you have to do is look at most surname projects to see that. Maybe somebody from your line from your surname hasn't tested yet.

    You should contact the administrator for your surname project and get their thoughts on your results, as from what information you are providing here and not knowing your surname or the family you are talking about it is hard to give you answers.

    Originally posted by georgian1950 View Post
    It will be interesting though because it looks like most of the close matches I've gotten on the Y-DNA are from NPE's.
    How do you know your matches are NPE's? How close are your matches and at how many markers do the matches occur? If you are matching many other surnames that usually means the relationship (if any) are back before surnames came about.

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  • josh w.
    replied
    Originally posted by georgian1950 View Post
    The original question was about measurement error (on the order of a point or two on a marker or two - nothing that would change the overall results). I got that question answered (something I think FTDNA should put in the FAQ). As happens with threads, they go off in somewhat different directions. I responded to people asking why I had the question in the first place and the additional questions that followed

    The norm for my surname line is R1b1a2. I tested I1. Nowhere did I question those results. I'm I1, confirmed by SNP testing that FTDNA did on its own accord. I'm just trying to figure out what surname I need to latch onto next.
    Good luck in your search. If I understand you correctly, only descendants of the disinherited son are I1 with all other relatives R1b1a2.

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  • georgian1950
    replied
    Originally posted by MMaddi View Post
    I'm a little confused. I've read all the posts in this thread, yours included. You started the thread by asking for verification that your results are somehow mistaken. This seems to revolve around your results indicating an NPE of some sort.

    Now with what you've posted, which I'm quoting, you seem to attribute your doubts to higher than normal mutation rates in your paternal line. Your second paragraph that I quote indicates that the line you believe you're related to is R1ba2, while your results indicate I1.
    The original question was about measurement error (on the order of a point or two on a marker or two - nothing that would change the overall results). I got that question answered (something I think FTDNA should put in the FAQ). As happens with threads, they go off in somewhat different directions. I responded to people asking why I had the question in the first place and the additional questions that followed

    The norm for my surname line is R1b1a2. I tested I1. Nowhere did I question those results. I'm I1, confirmed by SNP testing that FTDNA did on its own accord. I'm just trying to figure out what surname I need to latch onto next.

    Leave a comment:


  • MMaddi
    replied
    Originally posted by georgian1950 View Post
    My whole theory hinges on the family experiencing higher mutation rates than normal over the 300 years to the NPE. I'm already too far off in genetic distance with the 37 markers to have this match ruled as probable under the normal interpretation of genetic distance. I don't think adding more markers will counteract that problem.

    There was no inbreeding going on here. If the DNA followed the surname line, the haplogroup would have been R1b1a2. Instead it takes a turn to I1.
    I'm a little confused. I've read all the posts in this thread, yours included. You started the thread by asking for verification that your results are somehow mistaken. This seems to revolve around your results indicating an NPE of some sort.

    Now with what you've posted, which I'm quoting, you seem to attribute your doubts to higher than normal mutation rates in your paternal line. Your second paragraph that I quote indicates that the line you believe you're related to is R1ba2, while your results indicate I1.

    It's clear that such different haplogroups indicate with certainty that your paternal line is not descended from the ancestry you think it does. There's no getting around that. The haplogroups are defined by many SNPs, which rarely mutate. Two men from different haplogroups can't have a common paternal line ancestor for at least thousands of years.

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  • georgian1950
    replied
    Originally posted by MoberlyDrake View Post
    I was surprised when my cousin's Y-DNA matched another surname closely a year ago. The circumstances surrounding my great-grandfather's placement in an orphanage after his mother's death (her husband had died 4 years earlier) and his siblings being taken in mostly by neighbors, but NOT by any of their mother's 9 surviving siblings, looked very different to me after I got the results of that test than before.

    The Family Finder test proved that my great-grandfather was the son of a neighbor.

    I'm sure everybody on the board is tired of hearing about my particular NPE though. But I would recommend the Family Finder test.

    Carol Anne
    Thanks Carol Anne.

    Being new here, I hadn't heard it, but it is interesting.

    I think I do need to try Family Finder when the funds permit. Doesn't it have the best results over the nearest three or four generations? Here I'm working at a puzzle that dates back 300 years. Figuring out the cousin situation though might be the base I need to solve my problem from. Some of them might get better test results back to the MRCA that I am. It will be interesting though because it looks like most of the close matches I've gotten on the Y-DNA are from NPE's.

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  • georgian1950
    replied
    Originally posted by josh w. View Post
    Are you descended from the disinherited son. If so, I understand your concern. I simply am reluctant to form opinions about my ancestors when I have not walked in their shoes. There is a modest possibility that I have a NPE on my paternal line. I am happy to have any ancestors.
    Yes, I suspect I descend from the disinherited son. I'm not really concerned, but it has become a puzzle now. However a lot of people are descended from this line, and some might be upset to find that they really aren't in the family which they thought they were. Sooner or later DNA is going to reveal that reality to them, anyhow.

    If I'm correct about which surname I jump to, I suspect that is only temporary. That surname is a conglomerate of haplogroups, so I suspect I'll be looking for another surname to jump to further down the line (if I get that far).
    Last edited by georgian1950; 23 June 2012, 08:54 PM. Reason: spelling

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