I suspected that when my Grandfather's DNA came back it would confirm (once and for all) if our family had any Native American DNA. From my own DNA results I knew that this was highly unlikely. When I was a new researcher, the family stories about Native American heritage were very common. In looking at research done by other family members, several cousins had tried to identify which great-great grandmother they THOUGHT might have been at least 1/2 Indian. After running my DNA I felt justified in not being able to find any documents confirming that a great-great-grandmother actually was an Indian - Cherokee or otherwise (which is always the direction that family lore goes).
I've watched countless videos and read countless articles about DNA and how it is inherited. If the Native American match was as close as my grandfather believed it to be, it would certainly be in HIS DNA - even if it wasn't in mine.
My Grandfather is the oldest living member of my family. He is 89 years old (he'll be 90 in June). His results came back 100% European - no Native American DNA. I wasn't much surprised by the DNA matches from Great Britain (Grandpa's great-grandfather was born in Derbyshire). The European Jewish DNA did surprise me, as did the match from the Iberian Peninsula.
What was definitely absent was the Native American DNA, as I suspected.
My Dad's DNA results came back...and he doesn't have ANY Jewish DNA. None whatsoever. This totally floored not only my Dad, but also my Mom. We were all expected SOMETHING as far was his Jewish heritage was concerned.
And then I realized...assuming my family's background based on family lore (something that so many researchers fall into) is something that I am also guilty of.
It is because of these assumptions that actually running your family's DNA is so important. It's one thing to believe the family stories. Some of them do have elements of truth (or are actually true), but before believing them 100% make sure that you do your due diligence as a researcher. If the records take you to a brick wall (but not beyond), DNA may be the best source for you.