No announcement yet.

How to pick a SNP for a potential cousin to test for. R-F12788

  • Filter
  • Time
  • Show
Clear All
new posts

  • How to pick a SNP for a potential cousin to test for. R-F12788

    I have done the Big Y-700 test but recently was contacted by a cousin from Barbados but living in Canada. Our common ancestor is from Barbados born 1666 and is my 8th great-grandfather. He hasn't done any Y DNA testing but how do I choose a SNP for him to test for to confirm if he really is a cousin? R-F12788 is my Haplogroup and I believe it is very rare. Any help is appreciated. I am trying to learn as much as I can. Thanks in advance.

  • #2
    I don't see F12788 offered by FTDNA as a single SNP test. On FTDNA's Y-DNA haplotree, R-F12788 is under R-Z5054, then R-FT78151. There are only two men shown with that SNP: one with his ancestor from Sweden, the other with his ancestor from Barbados (perhaps you?). It may be a recently named SNP. Are you in a Y-DNA haplogroup project? It's best to get advice there. Perhaps there is some SNP pack that this cousin could try, if he doesn't want to do a Big Y 700 test.

    If your common ancestor is your 8th great-grandfather, then you are 7th cousins. The Shared cM Project has a .pdf which shows in a table on page 4, that for 7th cousin you might share an average of 13 cM, ranging from 0-57 cM. You MIGHT see him as a match if you both did an autosomal test (Family Finder). But, in the article "How Much DNA Do Distant Cousins Actually Share?" by CeCe Moore and Henry Louis Gates, Jr., it says :
    Fourth cousins will match each other about 50 percent of the time, but when you get out past the fifth-cousin level, the odds of sharing any DNA are less than 5 percent.
    So, you would likely have a more than 95% chance of NOT sharing autosomal DNA with this cousin. Y-DNA would probably be the best route to take, but get some project administrator advice first.
    Last edited by KATM; 5 December 2019, 11:54 AM.