DNA | Maps of History

When I was 17 I went to Ireland for the first time. Back then, my hair was dark brown, and my skin was fair. “You’re Irish,” proclaimed one new acquaintance.

“Not really,” I replied. “That last Irishman in our family was born in 1715.”

“See, it shows!” he crowed.

Now, as a family, we are pretty proud of our Irish heritage. Morris O’Brien, a firebrand if ever there was one, ran afoul of his English overlords, hied himself out of Dublin and emigrated to America in 1740 where he sired a pack of rowdy sons, the eldest named Jeremiah.

His six sons were among the residents of Machias, Maine, who fought the first naval engagement of the Revolution in June 1775, capturing the armed British sloop, Margaretta. Jeremiah O’Brien, my seventh great-grand-uncle, led the Colonials. All the O’Brien boys were later given letters of marque by the fledgling Continental Congress and had hair-raising adventures as they harassed British ships throughout the war.

There have been countless Jeremiahs hanging from my family tree since then (including my own son, born in the same week of the battle 201 years later). Five Navy ships, a torpedo boat, four destroyers and one World War II Army Liberty ship, the SS Jeremiah O'Brien, have been named after him. The O'Brien, which carried needed supplies on D Day, is now a living museum ship in San Francisco.

So, yes, my family is proud to have the O’Briens in our lineage but to the best of my knowledge the Irish were only a twig on a tree predominated by branches from Western Europe—German with a smattering of Alsatian (which is either French or German, depending on which decade you look at)—or from different parts of the British Isles.

Imagine my surprise, then, when I took a DNA test. It showed the expected 45 percent Western European but also a whopping 25 percent Irish. The remainder is split up into 12 percent English and very small percentages of Scandinavian, Iberian, Italian and Caucasian. I was thrilled! I was a walking history book tracing the progress of many human migrations and conquests.

The 10 percent Scandinavian was easy to account for. Clearly some distant forebear was a Viking who invaded Britain between the 8th and 10th centuries. In 1953, authors William Lederer and Eugene Burdick bestowed the sobriquet "The Ugly American" on US travelers for their arrogance and cultural ignorance but I am certain that my Norse forebears were far more intolerable tourists. Rape and pillage were their passports before they decided to colonize the coastlines and create such towns as Dublin, Wexford and Waterford in Ireland. Scientists estimate up to 20 percent of the Irish carry a Norse genetic imprint.

Or did the Scandinavian heritage come by way of Continental Europe, perhaps with the Norman invasion of England by William the Conqueror in 1066? No way to know, course, but it’s fun to speculate.

Reaching even farther back into history, my three percent Iberian takes me to the Mesolithic period (roughly 10,000 to 4,000 BCE), when genetic research tells us a significant portion of the Irish gene pool was contributed by populations emigrating to the Emerald Isle from the Iberian Peninsula of Spain.

The three percent Italian and two percent Caucasian are even more tantalizing. Did the distant Caucasus heritage begin when Julius Caesar’s son-in-law, General Pompey, led Roman legions into the southern Caucasus?

Or maybe that genetic package was added 10 years later when Julius Caesar marched his armies north into Germany to demonstrate his prowess and then on into England where the Romans set up camp for about three centuries.

That’s a long time and occupying armies who can’t pop home on leave invariably find the natives increasingly attractive. Before tiring of the climate (and local unrest) and pulling back to sunnier climes, Roman soldiers formed relationships with native women and these unions produced both a Romano-British population and cultural blending.

The only thing disappointing to me in my genetic heritage was the lack of Native American genes. Family lore gives strong credence to a connection to Indian tribes from Eastern Canada, but alas, I did not inherit that gene. It would be interesting to know if my siblings carry it on.

So, what does this all mean? Beyond my pleasure in being an amalgam of different epochs of human history—a living map of history—I think the main message in this day of division, with all its racial profiling, is that no one person is any one thing.

Why are we so obsessed with identifying ourselves as white, black or brown; Asian, Native American or Pacific Islander; Muslim, Jew or Christian? We are all the sum of our collective human experience, individually no better or worse than our personal actions dictate. Ethnic and racial differences exist but they are social constructs that should unite rather than divide, just as our genes mingle to produce each of us. True unity comes from recognizing, accepting and celebrating our shared humanity and diverse backgrounds.