One Shape All Along

In the neuron it's busy, two hundred letters of RNA waiting near the ribosomes, doing something there with how much of a protein gets made. Nobody's sure exactly what. In the skin it's the same letters, mostly quiet. In the egg and the sperm there's a little of it, and that's enough.

It came from a jumper, an Alu piece that settled in before there were monkeys or apes to tell apart, and about forty million years ago the cell found work for it. Things put to work usually stop travelling. This one didn't. It has no engine of its own. It rides LINE-1's, and what the engine grabs is the same end that holds on to the proteins where the work gets done.

So the job stayed put for forty million years and every so often a copy left anyway, into a monkey's germline, into an ape's, into one living person and nobody else.

Sometime in the last hundred thousand years a pox that only lives in skin picked up two pieces of it, and carries them still, bump to bump, from one person to the next, doing nothing anyone has found.

That isn't the brain gene abroad. It's the same letters without the room they work in. In Athens a broken pot was a sherd until someone scratched a name on it and voted with it, and then it had another name, for another use. If the pox ever finds work for those pieces, they'll get a third.

Nothing here was torn in two. Nobody had to choose between working and leaving. It was one shape all along, good at holding on and easy to pick up.