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1st cousin matches

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  • 1st cousin matches

    Is it possible that 1st cousins that were both tested - family finder test -
    did not show up as a match to each other?

  • #2
    Although I'd defer to a genetics expert, it seems extremely unlikely that two first cousins wouldn't match, and if that's what you're observing, the information seems to suggest that the two individuals aren't actually first cousins. Consider the numbers. On average, two first cousins would share around 850 cM; that is, 12.5% or one-eighth of each person's DNA would show up in the other person, too. Family Finder would show them as matches to each other even if they shared far less DNA--just scan the "shared cM" column in your Family Finder matches.

    For two first cousins NOT to match means that they somehow received little or no DNA in common from their shared grandparents. To estimate the odds, start with the idea that their relevant parents (the two siblings in the next higher generation) received little or no DNA in common from their shared parents. I suppose that's theoretically possible, but…