You think you know what you are. Then you get yourself tested and find out you're something else.
Me? Russian Jew on three sides, Austro-Hungarian on the fourth. Peasant stock. At least until I heard from an uncle who told me of a relation who sold clothes in Hazleton, Pa., - a cantor who'd come from Germany in the mid-1800s. I didn't know we had any fancy Germans, let alone Pennsylvanians.
Small difference, you might think. Nothing like the shock Julian Onorato received upon learning his family history.
He spent a good half-century seeing himself as an Italian American from South Philly by way of Camden.
"My grandfather [Onorato] was 100 percent Italian," he says. "My grandmother was 100 percent Polish, which should have made my father 50-50. But it doesn't work that way."
Onorato is 56, a Drexel-educated engineer, with salt-and-pepper hair and green eyes. He figures his looks come from his mother, who used to say she was a mongrel - a little French, some English, Irish, Italian, and Polish.
"My father was extremely dark-complected Italian with kinky hair," says Onorato, a pension-plan CEO who splits his time between Voorhees and Marco Island, Fla. He and his father looked so different that he remembers his mother thinking no one would know the two were related.
A couple of years ago, Onorato and his wife were watching Who Do You Think You Are? on TV, in which Emmitt Smith, the ex-Dallas Cowboys running back, was surprised to learn that in addition to being African, he was 12 percent European and 7 percent Asian.
Onorato started researching companies that analyze people's genetic composition, and picked an outfit called Dnatribes.com, which he paid to match his results with ethnic groups from 39 global regions.
He swabbed inside his cheek, then dropped the test kit in the mail and waited.
"I was really hoping to get a call from their chief scientist," he says. "I'm sorry to tell you we can't match you. You're an alien."
What he learned five weeks later felt just as foreign.
His DNA shows he is 62 percent Romanian, traced to a Roman Catholic people known as the Csango.
Only 19 percent of him comes from what is modern-day Italy.
He's 25 percent non-Caucasian, the largest share of that, 14 percent, being Western Australian Aboriginal.
Must be a mistake, he told the company. Maybe the results got mixed up. No, they told him. So he had himself tested again. Exact same result.
His conversation with one of the company's scientists launched a yearlong study of migration patterns, the Black Plague, the Crusades, and the Little Ice Age of Europe, 1550 to 1850.
Onorato's best guess is that his people shuttled between southern and eastern Europe, driven by disease, religious persecution, changing weather patterns, and the search for fertile soil.
But where does that non-Caucasian blood come from, he wondered. Probably from slaves who'd been kidnapped from Australia and sold along the Silk Road, the trade route that linked Asia and the Mediterranean.
Does knowing this make a difference in how you see yourself? I asked.
"I have always thought of myself as a white Italian American from South Jersey, and I'm really 25 percent non-Caucasian," he said. "I was very prejudiced. I don't think I wanted to hurt anyone, but I wanted to be able to live where I wanted to and pick my friends. I definitely wasn't very liberal with that stuff. I think as I grew up, that changed.
"My wife and sister say now I should be more sensitive to other people, which maybe I am. You always hear, regardless of religion, we're all made in God's image. Maybe we're all mixed up and not that uniquely different."
Contact columnist Daniel Rubin at 215-854-5917, email@example.com, or @danielrubin on Twitter. Read his blog at philly.com/blinq.