All his life, Cleon Brown, a 47-year-old police sergeant in Hastings, Mich., had thought he was a white man with some Native American blood.

That notion came from his father, who had black, curly hair and darker skin. Sergeant Brown’s father would tell him and anyone else who asked that his lineage could be traced to the Blackfeet Nation.

So Sergeant Brown stuck to that story.

But whenever people heard his name, Cleon, which he shared with his father, now dead, they would assume that he was a black man. He became a little suspicious of his actual heritage when his daughter, now 18, was given a diagnosis at birth for an illness that he said was typically found in African-Americans.

Ever curious about his background, he decided to take a DNA test from Ancestry.com last year. The results were surprising: He had zero Native American blood in him, but was 18 percent sub-Saharan African. The Times’s Race/Related newsletter [Sign up here to get it in your inbox] recently explored how people’s DNA matched with how they identified racially. Many of them were surprised, and even upset.