The Spool

Grandma Iness had a whole drawer of wooden spools, and every one of them was wound too tight.

"Look at this," Maya said. She held up a spool wound so hard the thread had cut a groove into itself. "You can't even find the end."

"Give it here," said Soren. He turned it over, hunting for the loose bit. There wasn't one. The whole length of green silk had been wrapped down so tight it might as well have been a solid thing. "Nothing to pull. It's locked."

They were supposed to be helping. What they were actually doing was avoiding their science project, which had failed.

"They were the same seeds," Maya said, for maybe the tenth time. "That's the part I keep chewing on."

The project was two trays of thyme, grown from cuttings off one single plant. Same plant. Same genes, exactly, down to the letter. One tray they'd kept warm. One tray they'd left cold near the window all month. And the cold tray had grown up short and stubborn and different, and stayed different even after they warmed it back up.

"Same instructions," Soren said. "Different plants. That's not supposed to happen. The genes are the recipe. Same recipe, same cake."

"Unless," Maya said, and stopped.

Soren waited. He had learned to wait.

"Unless some of the recipe is folded shut so you can't read it," she said.

Soren looked at the spool in his hand.

"Grandma," he called. "Why do you wind them so tight?"

Iness didn't look up from her stitching. "So they don't unravel in the drawer," she said. "A loose spool is a mess. A tight one keeps its secrets until you want them."

Soren went very quiet, then he set the green spool on the table between them.

"Okay," he said. "Pretend the thread is the instructions. All of them. Every gene, one long strand."

"It's a long strand," Maya said. "In real cells it's really long. It has to fit inside something tiny."

"So it has to be wound up. Around something." He grabbed an empty spool and wrapped a loop of thread around the wooden middle. "Around little spools."

"Are there little spools?" Maya asked. She was leaning in now.

"There have to be," Soren said slowly. "You can't cram a strand that long into a space that small without wrapping it around something. There has to be a thing it wraps around."

Maya picked up the locked green spool again and tried, one more time, to read the thread. To follow any single strand of it from start to finish. She couldn't. It was buried in itself.

"You can't read this one," she said. "Not because the thread is different. The thread's fine. You just can't get at it."

"And the loose ones?" Soren pulled a lazy, half-unwound spool out of the drawer. The thread hung open. You could see every strand.

"You can read those," Maya said. "Same thread. Both spools. One you can read and one you can't, and the only difference is how tight it's wound."

They both stared at the two spools. Same green silk. One open. One shut.

"That's the thyme," Maya said. Her voice had gone soft . "That's the cold tray. The genes aren't gone. Some of them just got wound shut. And whatever wound them shut, the plant remembered it. Even after it warmed up."

Soren was already writing. He drew a long line and then, all along it, a row of little circles, and wound the line around each one. Beads on a string. Around some, he pressed the loops in tight until you couldn't see the line at all. Around others he left them loose and open.

"So the little spools decide," he said, tapping the tight ones. "Not by changing the instructions. By hiding them. Wind it tight, the gene's still there, but nothing can read it. It's off. Loosen it, it's on."

"They're proteins," Maya said suddenly.

Soren looked up.

"The little spools. They'd have to be proteins. The cell builds everything out of proteins. Little protein spools, all down the strand, and the DNA wraps around them." She said it like she was reading it off a wall only she could see. "And the tightness is the switch."

"So a cell in your eye and a cell in your bone," Soren said slowly, "they have the exact same DNA. Every single gene. All of them. The whole book."

"But different spools wound tight," Maya said. "So they read different pages. That's the only difference. That's why an eye is an eye."

The drawer sat open between them. Forty spools. Forty different windings.

Soren put down his pencil. "Every cell in me has the whole thing," he said. "The whole set of instructions. For all of it. My eyes, my blood, everything. It's all in every cell. It's just wound shut in most of them."

"You're carrying the entire book around," Maya said, "in every single cell. You're just only reading one page in each place."

Grandma Iness reached past them into the drawer, without looking, and pulled out a spool wound so tight the thread had gone dark with age.

"This green," she said, "was my mother's. I never used it. Couldn't bear to unwind it." She turned it in her fingers. "But it's still green under there. All of it. Waiting."

Maya took the old spool from her. She found the buried end with her thumbnail, worked it free, and pulled.

The thread came loose an inch, then a foot, dark on the outside and bright green underneath where the years hadn't reached, unwinding into her open hand.