About 6 months ago I had my DNA tested through Ancestry and am currently building my family tree. In my DNA origins it is showing, on my paternal side, that my ancestors 100% originated in East Mayo and South Sligo. However I know for sure that my paternal grandfather was born in Cork. I must be honest here, I'm unsure if that means the city of Cork or County Cork, but either way it is nowhere near either Sligo or Mayo.

Why would my DNA origin not be showing this Cork connection?

I have no relatives that I can ask about my father's family, and as I am relatively new at this I'm struggling to understand some of the information.

1 Answer 1


First, understand that the Ancestry analysis can only be as good as the data they have collected.

They have found that your DNA has similarities to people who presently live in the Mayo/Sligo area. So, they have concluded that you have ancestors from the May/Sligo area. But, the DNA test alone won't tell them how far back the connection is. It could be much further than 2 generations.

I am guessing that a family needs to be in the same area for about 5 generations for their DNA to mix with the population in the area enough to show similarities. Probably fewer generations if the immigrants to the area are the dominant group.

They can also combine the DNA information with known historical migration patterns to make more conclusions.

Here is the analysis for my DNA. I have marked the areas that I know my ancestors lived with red circles.

My father's ancestors are from Croatia, very close to where Ancestry concluded. But, historical experts tell us that Croatia was mostly settled from the northeast of Croatia (many hundreds of years ago). That explains why my DNA has similarities to people from Russia/Ukraine/etc.

It looks like they got my northeast German ancestors wrong. But, not really, this just means that my German ancestors did not live in that area long enough to share their DNA with the present population.

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  • Thank you, it makes much more sense now. So my ancestors are from the Sligo/Mayo area. My grandfathers family have moved to Cork (where he was born) and he has moved to England in the North East where he lived and family still live. But as that is only two generations that will not show in DNA origins.
    – Elaine
    Commented Apr 22, 2023 at 10:36

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