I am trying to determine if my half sister had a different father than the one she grew up with. I was given a name of who the father could be. He has passed away but his son took a DNA test on Ancestry. My half sister's son did as well. The relationship is at 439cMs.

Is there any chance that this relationship could be a half uncle rather than half cousin?

1 Answer 1


From The Shared cM Project 3.0 tool v4 for 439 cM the possibility of such a match being a half first cousin (Half 1C) is far greater than it being a half uncle.

Nevertheless, the latter is also possible:

Relationship probabilities (based on stats from The DNA Geek)

83.17% Great-Great-Aunt / Uncle Half Great-Aunt / Uncle Half 1C 1C1R Half Great-Niece / Nephew Great-Great-Niece / Nephew

15.80% Half GG-Niece / Nephew† Half GG-Aunt / Uncle† 2C Half 1C1R 1C2R

1.03% Great-Grandparent† Great-Grandchild† Half Aunt / Uncle† Half Niece / Nephew† 1C† Great-Aunt / Uncle Great-Niece / Nephew

† this relationship has a positive probability for 439cM in thednageek's table of probabilities, but falls outside the bounds of the recorded cM range (99th percentile)

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