Belief in Native American ancestors is also common among African-Americans. Google that topic for articles.

As a white Southerner, I recall family speculation about Native American ancestors. My impression as a kid was that Native blood signified toughness and ferocity, in line with TV portrayals. That was the attraction of the family legend to us.

The family “evidence” for possible Native ancestry was a portrait of my great-great grandmother Betsey who had “really high cheekbones”. Many years later I discovered that Betsey was not only not Native American but she actually was a descendant of Virginian aristocracy (Jefferson and the like). We were disappointed.