I did one of those Ancestry DNA tests, and it certainly opened my eyes.
This is why....
I have been doing my family tree for 15 years or more, and all of my mother's side are Yorkshire folk, right back to the early 1700s.
I never knew my father, and Mum told various tales as to who he was.
There were however whispers (mostly from my Mum's own sister) that said my Uncle was my father. Now he, and his family were all Scots.
This is the mix my DNA test came up with.
"Ethnicity Estimate
Your DNA looks most like DNA from these 4 world regions
We compare your DNA against a worldwide reference panel to see which populations your DNA looks most like.
Scotland47%
Ireland19%
England & Northwestern Europe19%
Sweden & Denmark15%
See other regions tested
1,500+"
What would you suppose from that? I know what I'm thinking.