Both sets of my American great-grandparents were travelers—immigrants who arrived to New York City and then traveled back and forth to Europe via ship when they could. All four of my grandparents flew on jets as soon as commercial passenger travel began. I was born in Australia to an American and an Aussie who took me all over Asia and the Pacific islands before I turned 3 (one of my first foods was satay in Bali). I've been to 26 countries and know enough Spanish and French to get around (and sufficient Italian and German to get by).

I have taken unpaid time off at every one of my regular office jobs because in the U.S. vacation time is just ridiculous. Then I went freelance because even that much time off wasn't enough. I wasn't interested in lounging in hammocks, but traveling, so now I travel and work at the same time. My uncle never traveled anywhere and we all though there was something wrong with him.

I get depressed when I don't have a trip planned and I've literally felt my feet itching when I'm looking at flights. I assume I have the wanderlust gene.

No, that's not just me assigning a trendy idea to my predilection for a good long walkabout.

“No other mammal moves around like we do,” Svante Pääbo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told National Geographic about humanity's peripateticism.

“We jump borders. We push into new territory even when we have resources where we are. Other animals don’t do this. Other humans either. Neanderthals were around hundreds of thousands of years, but they never spread around the world. In just 50,000 years we covered everything. There’s a kind of madness to it. Sailing out into the ocean, you have no idea what’s on the other side. And now we go to Mars. We never stop. Why?”

Starre Vartan swimming in a mountain pool in the mountains of Mexico's Sierra Madre mountainsStarre Vartan swimming in a mountain pool in the mountains of Mexico's Sierra Madre mountains. (Photo: Starre Vartan)

The restless gene

Probably because 20 percent of us have a gene (or a combination of genes) that compel us to get out of town on the regular. One of them is a variant of DRD4, which regulates dopamine and in turn affects behavior motivation. The variant, DRD4-7R, has been connected by quite a number of studies with behaviors and drives that will sound familiar to my fellow travelers. It's been linked to taking risks, interest in exploring new places and meeting new people, being excited by new foods, and experimenting with drugs and sex — in a word, a taste for adventure. (In animal tests, similar genes have been found that increase interest in movement and novelty.) Some of us don't just love change, we crave it.

You might be more or less likely to carry the gene depending on if your ancestors were part of migratory populations. According to the first big study on this subject from 1999, "...we found that, compared to sedentary populations, migratory populations showed a higher proportion of long alleles for DRD4," writes Chuansheng Chen, a psychologist at UC Irvine. "We discussed the adaptive value of long alleles of DRD4—a genetic trait that has been linked in some studies to the personality trait of novelty-seeking and to hyperactivity— in migratory societies and the possibility of natural selection for a migration gene."

So this is a gene that, in certain populations, was selected for and then passed that gene onto their children. While many people who went to sea in early ships with no idea what was on the other side of the ocean perished from scurvy, high seas or starvation, those who made it to new places tended to do better than the people they left behind.

OK, that last bit is pushing the science a little further than the data indicate, and most of the researchers who study this topic agree that it's not one gene that causes such a significant human behavior as travel and exploration. After all, you not only have to have the desire to go, but also the physical (and mental) health to do so. And it doesn't hurt to be smart and innovative in stressful situations, traits that all successful early explorers had in spades.

little girl wearing aviator glasses with plane and stuffed bearKids who grew up traveling may be inclined to have the wanderlust bug. (Photo: Sunny studio/Shutterstock)

Nature and nurture

And of course it's not all nature — nurture has something to do with it too. I was never taught to be afraid of flying, for instance, as my grandmother was a pilot. And because I never ate kid food but was expected to eat whatever people ate wherever we traveled, I never learned to shy away from "weird" dishes. (Also, nobody in my family would have listened to me if I had complained about such a thing.) And I was encouraged to explore by myself on my bike and on foot, so I was given the tools to be able to feel comfortable alone, and also figure out how to get out of difficult situations on my own — which is incredibly important when you are in a country where nobody speaks your language.

Lastly, of course, you need the means to travel, whatever your genes. Whether it's a better boat — which may have stopped Polynesian peoples from traveling for a few thousand years according to this fascinating National Geographic story — the money to buy a plane ticket, or being able to speak another language (or having a facility with languages), the ability to travel matters just as much as the compulsion.

Human origins began in Africa, but at around 70,000 years to 50,000 years ago, we started walking and haven't stopped since. Our genes likely played a role, but, as with all things human, there's other interesting parts of the story having to do with culture, gender and class. And dismissing them for a simple genetic explanation takes what makes us human out of the equation. But if you lie in bed at night, dreaming of what you'd see if you won a free trip to Japan, or if you stare longingly at globes and drift off while they spin beneath your hungry fingers, there might be something deep inside you — pushing you to book that next ticket — that has been passed along from your adventurous ancestors.

Do you think you have the wanderlust gene?