After the Fall, Before the Fall, During the Fall

MARCH 2014

On the high plateau of the Brazilian state of Paraná, the arabica trees rustled in a gentle rain. Drops pattered off dark green, lance-shaped leaves, cascading down until they touched the soil. The coffee berries were small, not ready for harvest until the dry season, months away. At the far edge of the vast field, a fertilizer drove slowly among the rows of short, bushy trees, some of them fifty years old. A rabbit raced ahead of the advancing machinery.

Deep underground, something happened.

Nonmotile, rod-shaped bacteria clung to the roots of the coffee trees, as they had for millennia. The bacteria stuck to the roots by exuding a slime layer, where it fed on and decomposed plant matter into nutrients. In the surrounding soil other bacteria also flourished, carrying on their usual life processes. One of these was mitosis. During the reproductive division, plasmids were swapped between organisms, as widely promiscuous as all of their kind.

A new bacterium appeared.

Eventually it, too, began to divide, not too rapidly in the dry soil. By and by, another plasmid exchange took place, with a different bacterium. And so on, in an intricate chain, ending up with a plasmid swap with the nonmotile, rod-shaped root dweller. A mutation now existed that had never existed before. Such a thing happened all the time in nature—but not like this.

Above ground, thunder rumbled, and the rain began to fall harder.