Chapter 3: Neurogenesis

Over the following years the scientists worked to develop their knowledge fast enough to keep pace with their decaying bodies. As they made progress, the goalposts moved with them. They renewed one organ or bone after another, getting quicker and picking their targets carefully, so that none of them died.

In fact 130 years after the impact, they’d worked their way through to the last ear and fingernail, and the ship appeared to be manned by four fresh-faced girls with clear, sparkling eyes, agile bodies and smooth, unwrinkled skin.

There was just one big issue left.

“Okay,” Susan said over breakfast one day, “brain cells. We’ve slowed down the deterioration but it’s still happening, and I’m getting too forgetful to be effective now. In fact we all are, let’s be honest. We need to get started while we still can.”

“Yes, it’s time,” agreed Melissa. “Neurogenesis. Well we have the theory of how to trigger it...”

“I’ll go first if you like,” offered Leila, “I’ve been pretty much dependent on following written procedures anyway, the last few years. My memory’s so hit-and-miss these days I can’t trust it at all!”

“Okay, thanks.” Susan knew, as they all did, that it was best to have the three scientists doing the operation, in case something went wrong. Brain cells didn’t renew that much after early childhood, normally, so it was even more uncharted waters than the previous processes. She smiled at Leila, thinking how brave she was.

Leila smiled back, at this person who looked like a teenage girl but was possibly going to save her life, forever, together with the other two teenage-looking girls! The whole thing was insane. But what she felt for them was ... well it was like the four of them were the only people in the world; or in the Universe, more accurately.

Which perhaps they were, because they hadn’t heard anything from Earth in over a hundred years, and what they had heard had sounded as though the neverending conflict between the kleptocracies and the democracies had gone nuclear. There was a time lag now of over two hundred years anyway, so it was impossible to know. But she did know the four of them were on their own - to the ultimate extent it was possible to be.

They spent the next month making sure everything Leila knew about piloting the spacecraft was up-to-date in the computer knowledgebase, and she’d written out her diary with her life story and everything she could remember about herself. Then they were going to put her in a managed coma and signal her brain to grow new cells like a baby, with pluripotent DNA from her hippocampus, modified to act in all the other areas of her brain.

“I want you to know,” she smiled as she lay down in the compact little operating theatre in the Research Unit, “don’t feel bad if it goes wrong, because I would die anyway, and don’t freak out when I don’t remember you when I wake up. I love you, okay? I’ll just have to learn to love you all over again, that’s all.”

“We know,” Melissa smiled back, as Susan connected the drip to the cannula. “We’ll be here for you. You’ll still be the same person and we’ll still love you too.”

Isobel didn’t trust herself to say anything, she just gave Leila’s hand a squeeze, and felt the bigger hand squeeze back.

Two years later Leila opened her eyes. She lay still while her senses tried to filter millions of unstructured, unknown signals of light, sound, smell and touch.

Movement drew her eye. A face. Faces. Instinct told her what the smiles meant, and after a second made her smile back.

The concept of people was innate too, and so was grasping the hand that she felt slide into hers. One hand on top, as well. They were warm and good.

There were sounds, that came from the face near her. The sounds felt good as well, but apart from that they didn’t mean anything.

“Alright,” Susan was disconnecting the catheter, making herself stay calm. “She can see and feel. Say something Melissa.”

“Leila?” said Melissa.

Leila’s eyes moved to look at her, but slowly, and blankly.

“She can hear,” murmured Isobel, blinking back tears of relief, tinged with sadness, “but she doesn’t remember who she is, or us.”

“That probably means she’s renewed everything,” Susan slid a supportive arm round Isobel.

“Let’s touch and smile, to start with,” Melissa remembered the procedure they’d developed.

The three old women, who looked about sixteen apart from the knowing glint in their eyes, gathered round Leila, who also looked about sixteen but with trusting infant eyes. The scientists stroked and smiled, while trying to answer the question they’d discussed endlessly: was this still Leila?

Her smile was the same, but the confident and occasionally commanding personality wasn’t there any more. Or not yet. She was dependent, with no knowledge.

“Okay let’s get her up,” said Susan, and pulled gently on one big hand. They’d used genetics to stop her muscles wasting, and kept her in a section of the zero-gravity hub so she didn’t have pressure sores, but they didn’t know what her coordination would be like.

Leila let herself be pulled off the gurney while the three smaller beings held her arms. She tried to copy how they stood. She swayed forwards, leaning heavily on two of the beings. One of them staggered and the other one collapsed, so she made for the safety of the floor, on hands and knees. The beings were making a lot of noise.

“She’s alright, give her time,” said Susan.

Isobel picked herself up and dropped onto hands and knees next to Leila. She nudged up to her and gave her a kiss on the cheek. “Okay copy me, when you’re ready,” she smiled. She stood up, holding onto the counter, while Leila watched. Leila thought about it for a minute, then copied her. She stood, swaying slightly but upright, leaning on the counter.

“Great,” Susan smiled and stroked the tall girl. They all knew copying was going to be the way for Leila to learn. They’d make a start on language after some food.

Eighty years later Susan’s brain cells had been renewed, the last of the four, and like the others she’d re-learned language and what they were doing with genetics, and all about the crazy mission to find a solar system on the basis of an astronomical prediction.

It had helped of course that she had a full adult complement of vigorous new brain cells, and that those cells (or their identical predecessors, strictly speaking) had once formed one of the more effective human brains on Earth.

Her companions had had a similar advantage too, so with the computer and the ship’s knowledgebase they’d long been back at work on genetics research, albeit without the urgency they’d had before. In the meantime they’d managed to get rid of ovulating and periods, at least.