I grew up with her, just the two of us. She was a wanderer, not happy unless she was going somewhere. Her restlessness had us moving once every year or two or three. Everything was an adventure, every weekend a journey. Out of Denver, she’d take me up into the Rockies to camp in a tent along cold, tumbling streams. We ate out of foil packets and climbed mountains until we could see everything, a continent disappearing over the edge of the earth all around us.
To live is to move. Any species will tell you that. Genes require frequent stirring and new niches must found. Tendencies toward novelty seeking and risk taking have a chromosomal expression. Some of us are just more struck than others.
Factors for movement can be changes in climate, resource abundance, scarcity, conflict, etc. This is known as environmental dispersal, reasons for leaving coming from the outside. A more complex and less understood phenomenon is called innate dispersal, the drive to move coming from within.
Fruit flies are one of the easiest live specimens to play with, and the foraging genes in their larvae have been turned up and down by researchers to see what might happen. They found that increased expression in foraging, which essentially boosted innate hunger, resulted in the maggots wriggling farther away than the ones with foraging genes turned down or just left alone. Even if food was plentiful and nearby, the heightened foragers kept going.
In human individuals, a statistical increase in the number of dopamine receptors is found among those who tend to be risk takers and far-travelers. The elongation of the dopamine D4 receptor gene is notably correlated with restlessness and novelty-seeking, a sort of automatic itchiness built into some people’s systems. It is also connected to autonomic nervous system dysfunction, attention deficit disorders and hyperactivity
A study of the genes of more than 2,000 prehistoric individuals worldwide, ranging between 1,000 to 30,000 years old, found that this genetic marker is more prevalent among those who migrated, while sedentary peoples tended to have less pronounced D4 markers. The Americas serve as a window into how this might have worked. Prehistoric cultures from South America show the greatest expression of D4, 69 percent of both modern and prehistoric Native populations having elongated alleles, perhaps for the longer journey required to arrive at what was then the most isolated continent in the world. Central America comes in second with 42 percent of the population having pronounced D4, and North America, with easiest access via the land bridge, shows 32 percent. Though the research is disputed and is peppered with uncertainties, D4 in the genes offers an internal explanation for why people might up and go. The more strongly it is expressed, the farther you are likely to move.
I can’t tell you what is in my mother’s genes, but all my life I have moved. It came to me through her blood or through her teaching. I was the kid in school with the jackhammering knee, my eye going from clock to window to door to clock. If they’d known what to do with me, I’d have been sedated.
As if following a secret gravity, I’ve continued my peripatetic nature well into adulthood. A student of landscapes, studier of horizons, I am one, perhaps like you, who can’t stay put. But maybe I am one of those who can save the species. We find the fall backs, the new breeding grounds. We learn to fly, we travel to space. We know the object is not perpetual growth but perpetual motion.