From: john1@s145802280.onlinehome.fr   
      
   On 04/12/2020 18:54, Ruth Wilson wrote:   
   > Following on a bit from John's post, I haven't used FamilytreeDNA, only   
   > Ancestry. I can identify all but one of my 1st-3rd cousins on there (the   
   > unidentified one hasn't replied ... might try again), but I'd like to   
   > understand a bit more about the more distant ones.   
   >   
   > Now, I am no scientist, so please don't baffle me with technicalities! I   
   > have heard that under, say, 20cM, the DNA matches can be by chance   
   > rather than being a certain relative. Does that sound right? (I have   
   > still found a known 3rd cousin with a smaller than expected DNA match)   
   >   
   > Now, I understand that we don't inherit DNA in equally shared amounts. I   
   > have lots of matches from Great grandfather G - is that because his DNA   
   > has been passed on in greater amounts, or because he had lots of   
   > descendants and they have taken DNA tests in large numbers? Does that   
   > mean I will have proportionately less DNA from Great grandfather M and   
   > will need to look further down the list for possible matches? (I hope   
   > this makes sense and you see what I am asking!)   
   >   
   > I know on my paternal line, the matches will be more distant. Of my   
   > great-grandfather's children, only my grandfather had   
   > children/grandchildren who lived to adulthood.   
   >   
   > I have a lot of matches with an identifiable group who emigrated from   
   > Argyll to Canada, although we can't pin down a line. Does the fact that   
   > I have matches with at least 6 of this line make a pretty strong   
   > likelihood of a shared descent? (they do share a family surname - Craig   
   > - that I had tentatively linked to eastern Scotland, but need more proof   
   > - or otherwise. Of course, a couple of female generations, or   
   > illegitimacy, and it could link into another of my Scottish lines!)   
   >   
   > It seems John is a bit dubious about it, but is it worth uploading DNA   
   > results to other sites? Family Tree DNA does get good reviews.   
   >   
   > Thanks   
   >   
   > Ruth   
      
   I'm not dubious about uploading to other sites. You will, in all   
   probability get new matches as some people only do a DNA test at one   
   site and just do not upload the data to another site or it is a format   
   where they can't.   
      
   The problem is interpreting the results. The trees on any site often   
   have errors and I've found that even when you give someone evidence e.g.   
   a birth certificate, they refuse to believe their tree is incorrect and   
   do not make any changes. Then there are those with only a nickname and   
   no tree,or a tree of perhaps seven individuals, themselves, their   
   parents, and their grandparents, all labelled private, etc. Or those   
   with very large trees, all of which is private, but which the DNA   
   service show have no common names. So although you may have a DNA match   
   to someone, identifying why is usually very difficult.   
      
   In simplistic terms most of the trees everyone will have researched are   
   most often mainly husband/wife/children groupings frequently developed   
   around census data. But those trees are quite likely to be incorrect in   
   genealogical/DNA terms.   
      
   Although it is likely the wife (or possibly a wife from an earlier   
   marriage) is the mother of the children in those families, the number   
   where the father is the husband is quite possibly less.   
      
   I have identified several children who are the offspring of unmarried   
   daughters (father unknown) but who appear in census records as the   
   children of the daughter's parents (revealed by the birth certificate).   
      
   I have wives who appear to have died in childbirth or soon after but   
   there is no record of a stillbirth or a child but one of about the   
   correct age appears in the family of a cousin, so acquires a different   
   surname, or a child appears in a family of childless couple who have   
   perhaps been married for perhaps ten or more years (so raising some   
   doubts).   
      
   Then there are the young (or not so young) males fathering children,   
   locally or anywhere else (including abroad).   
      
   So those are some of the ways the family groups can diverge from the DNA   
   results (I'm sure someone will suggest others). In all those cases DNA   
   matches are very likely to show links into families which we know   
   nothing about from our research.   
      
   As I mentioned in another reply, my mystery grandfather was the father   
   of a child to a 22-year old unmarried woman in East London in the 1920s.   
   That is all the information there was in the family. If any of the five   
   siblings or the mother of my grandmother knew the name of the father   
   they took it to their grave without divulging it. So DNA matching is   
   currently the only route to possible identification.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)