Atlas of a Lost World

We need each other. One of the reasons for migration is the bond of society, an urge to be together. A group might keep going for no other reason than the hope to find others.

We think of ourselves as different from other animals. We extol our own tool use, congratulate our sentience, but our needs are the same. We are creatures on a planet looking for a way ahead. Why do we like vistas? Why are pullouts drawn on the sides of highways, signs with arrows showing where to stand for the best view? The love for the panorama comes from memory, the earliest form of cartography, a sense of location. Little feels better than knowing where you are, and having a reason to be there.

A genetic study of more than two thousand prehistoric individuals worldwide, ranging between one thousand to thirty thousand years old, found that this pronounced D4 marker is more prevalent among those who migrated as compared to those who maintained a long genetic history in one place. Among Native American genomes and those of their ancestors, the presence of D4 is correlated with an individual’s distance from the land bridge. North America, with the closest access to the land bridge, shows 32 percent of samples with D4 elongation. Central America comes in ahead with 42 percent, and South America reaches an average 69 percent, as if people needed that much more umph to reach that far south. Too high in D4, though, you’d never be seen again, a seed blown beyond all horizons.

The increased genetic presence of the dopamine receptor known as D4 is correlated with restless behavior and what is known as “novelty-seeking”—the kind of people who are reckless or adventurous, in need of something new.

The drive may be innate. Some fruit flies, when they’re young, are adventurers. When they first chew out of their pinhead eggs as larvae, some wriggle farther than the others. Scientists have studied these individuals and identified a genetic locus connected to foraging, what is known as a rover allele. When the presence of rover alleles is increased, a larva will pass up food and creep toward the limits of its petri dish. Such larvae tend to be found dead around the edge of the dish, their journey more important than living.

The popular version of the first American colonization is “people on their way here” — like immigrants on their way to Ellis Island, bustling to see ahead. But people weren’t on their way to North America, because nobody even knew North America existed, and so their arrival was an exploration every foot of the way. There might have been adventurers — crazies at the edge of all human societies, willing to do nearly anything, wild-eyed characters heading always for the hills — but most people would have spent their time surviving in hungry country, weathering the unstable ups and downs of worldwide glaciation, in the company of several tons of animals per square kilometer. Life was hard enough, and short enough, already. Why go off on a lark across the ice when there was already so much to do where you were?

People once traveled at the speed of two feet, or possibly a paddled boat, but no faster. Most of our evolution was at this pace, one step and the next. The way we zoom around in cars and planes has changed the way we understand the dimensions of geography. Distances are abstract, unapproachable; what you see when you open the shade on an oval window in an airplane and look down thirty thousand feet is walkable land, mesas and mountains appearing ahead, vanishing behind. In the Ice Age, to know about a place was to have been there, or at least heard tell of it. Word of new places came in the form of birds from far away and a different grit to the rivers.

For me, there was no past. I was a minor god striding through the world, leaning from the bow of our canoe as if into a creation story. I could name things as I saw them, a colonist at heart. That is a bear, that is a cumulus cloud. This is rain, this is sunset. The world was opening to me, unknown and undiscovered as far as I could see.