Happy belated St. Patrick’s Day.

My mother’s favorite holiday. Although she was not at all Irish.

But as my sister Kathleen always says, “She thought she was.”

We Irish-Americans have made St. Paddy’s into a day of high pride and celebration. It’s become such an exuberant celebration that all sorts of Yanks now put on the green, drink more beer than they should, and eat corned beef and cabbage for the day.

Which to my understanding is not the meal of choice in the real Ireland on St. Pat’s, which historically at least was a religious holiday. But that’s another story.

St. Patrick’s in America, of course, is a call back to ancient roots, family histories for a people uprooted by famine and deprivation, willingly and unwillingly transplanted to a land dominated by folks of other complexions, other habits. It’s a primal echo.

I remember the first time I became aware of ethnicity and asked my mother what ours was.

“We’re Irish,” she said affirmatively although of course she knew very well that she herself was of full-blooded Italian background. Although my DNA test now indicates that even that was only half true. My good and generous mother’s blood lines evidently also hearkened back to Spaniards on the Iberian peninsula, Ashkenazi Jews in Eastern Europe and even a group of unknown people from Central Asia of all places.

Maybe someone went on the trips with Marco Polo.

The sadder question, however, is why my olive-skinned mother, growing up in 1930s Massachusetts, would feel compelled to identify with people of paler skins. The truth is that any observer of American history can tell you the deeply-ingrained reasons for that.

My father, who had very fair skin and dark hair, was a full-blooded Irishman, his parents being from Cork and Mayo. But again the DNA says there’s a good swath of his genes that only the English and Spanish carry, as well as some highlights from Scandinavia and northwest Europe.

It’s become all the rage to trace your ancestry nowadays and it’s a lot of fun. Not a few of us have learned that we will never qualify as pure breeds for the Westminster or any other dog show.

But with racism again re-asserting its ugly head under the current president (who by the way is of German and Scottish, not English colonial, background), the ability to trace ancestry is probably a good thing. If for no other reason than to convince us, as the scientists have long ago concluded, that race is a man-made conception.

For the most part, there is no such thing as black or white but a continuum on which all human beings exist — we’re all the same and we’re all different, with no dividing line between any color except for gradations. Our geography and culture plays a much larger role in who we are and who we become than our genes do.

There was a time in this country when many Southern states followed the “one drop” rule. That being, if your ancestry included even one ancestor who was black, then you were black. This was a time when enslaved African-American women were often raped by their white masters. Their often fair-skinned slave children were the visible testament to America’s tragic flaw and our long challenge in coming to terms with it. The Nazis had similar obsessions with partial Jewish ancestry in the years leading up to the Holocaust — there is something deeply ingrained in human beings that is always fearful of the other.

For millenials, all this talk about Irish-Americans and Jewish-Americans and African-Americans is outdated. The primal echoes that give ancestral pride its meaning is further and further from their consciousness. They are Americans, with their primal identity coming from the country’s best customs and freedoms. They value a world that understands people as having worth for who they are and how they behave, not whose blood they are carrying.

That is, of course, a good thing.

The current prime minister (taoiseach) of Ireland, Leo Varadkar, is the son of an Indian father and an Irish mother. He is gay and the leader of what has become one of the most progressive countries in Europe.

And like my mother, St. Patrick himself was not Irish at all, but a British Roman who went by the name Patricius before he fell in love with the country he was kidnapped to.

Like my mother, St. Pat took the best of Ireland and made it his own.

Jack Spillane is the Sunday and editorial page editor of The Standard-Times.