John Scalzi - The Ghost Brigades

Presented with this bountiful new pool of potential recruits, the Colonial Defense Forces found it had the luxury of making certain staffing choices. The CDF would no longer ask colonists to serve in the CDF; this had the salutary effect of allowing colonists to focus on developing their new worlds and making as many second-generation colonists as their planets could handle. It also eliminated a key source of political tension between the colonists and their government. Now that the young adults of the colonies were no longer extracted from their homes and families to die on battlefields trillions of miles away, the colonists were largely unconcerned with the ethical issues surrounding genetically modified soldiers, particularly ones who had, after all, volunteered to fight.

In the stead of colonists, the CDF chose to select its recruits from the inhabitants of humanity's ancestral home, Earth. The Earth held billions of people: More people on that single globe, in fact, than existed on all the human colonies combined. The pool of potential recruits was enormous—so large that the CDF further limited its pool, choosing to take its recruits from comfortable and industrialized nations whose economic circumstances allowed their citizens to survive well into their later years, and whose social blueprints created both an overemphasis on the desirability of youth and a parallel and profound national psychic discomfort with aging and death. These senior citizens were patterned by their societies to be excellent and eager recruits for the CDF; the CDF quickly discovered that these senior citizens would join up for a military tour even in the absence of detailed information about what such a tour entailed—and indeed, recruitment yields were higher the less the recruits knew. Recruits assumed military service in the CDF was like military service on Earth. The CDF was content to let the assumption stand.

Recruiting seniors from industrialized nations proved so successful that the Colonial Union protected its recruiting pool by banning colonists from those nations, selecting its colonist pool from nations whose economic and social problems encouraged the more ambitious of its young people to get the hell out as soon as humanly possible. This division of military and colonist recruitment paid rich dividends for the Colonial Union in both areas.

The military recruitment of senior citizens presented the CDF with one unexpected problem: A fair number of recruits died before they could join the service, victims of heart attacks, strokes, and too many cheeseburgers, cheesecakes and cheese curds. The CDF, who took genetic samples from its recruits, eventually found itself stocked with a library of human genomes it wasn't doing anything with. The CDF also found itself with a desire and also a need to continue experimenting with the body models of the Colonial Defense Forces to improve their design, without cutting into the effectiveness of the fighting force it already had.

Then came a breakthrough: an immensely powerful, compact, semi-organic computer, thoroughly integrated with the human brain, which in a moment of profoundly inappropriate branding was lightly dubbed the BrainPal. For a brain already filled with a life's worth of knowledge and experience, the BrainPal offered a critical assist in mental ability, memory storage and communication.

But for a brain that was literally tabula rasa , the BrainPal offered even more.

Robbins peered into the creche, where the body lay, held into place by a suspension field. "He doesn't look much like Charles Boutin," he said to Wilson.

Wilson, who was now making last-minute adjustments on the hardware that contained Boutin's recorded consciousness, didn't look up from his work. "Boutin was an unmodified human," he said. "He was well into middle age when we knew him. He probably looked something like this guy when he was twenty. Minus the green skin, cat's eyes and other modifications. And he probably wasn't as fit as this body is. I know I wasn't as fit in real life at age twenty as I am now. And I don't even have to exercise."

"You have a body engineered to take care of itself," Robbins reminded Wilson.

"And thank God. I'm a doughnut fiend," Wilson said.

"All you have to do to get it is get shot at by every other intelligent species in the universe," Robbins said.

"That is the catch," Wilson noted.

Robbins turned back to the body in the creche. "All those changes won't mess with the transfer of consciousness?"

"Shouldn't," Wilson said. "The genes relating to brain development are unaltered in this guy's new genome. That's Boutin's brain in there. Genetically, at least."

"And how does his brain look?" Robbins asked.

"It's looks good," Wilson said, tapping the monitor of the creche controller. "Healthy. Prepared."

"Think this will work?" Robbins asked.

"Got me," Wilson said.

"Good to see we're brimming with confidence," Robbins said.

Wilson opened his mouth to respond but was interrupted as the door opened and Generals Mattson and Szilard stepped through, accompanied by three Special Forces decanting technicians. The techs went straight to the creche; Mattson went to Rob-bins, who saluted along with Wilson.

"Tell me this is going to work," Mattson said, returning the salute.

"Lieutenant Wilson and I were just talking about that," Rob-bins said, after a nearly imperceptible pause.

Mattson turned to Wilson. "And, Lieutenant?"

Wilson pointed to the body in the creche, being fussed over by the technicians. "The body is healthy, and so is the brain. The BrainPal is functioning perfectly, which is no surprise. We've been able to integrate Boutin's consciousness pattern into the transfer machinery with surprisingly few problems, and the test runs we've done suggest there won't be a problem with transmission. In theory, we should be able to transfer the consciousness like we do with any consciousness."

"Your words sound confident, Lieutenant, but your voice doesn't," Mattson said.

"There are a lot of uncertainties, General," Wilson said. "Usually the subject is conscious when he transfers over. That helps with the process. We don't have that here. We won't know whether the transfer is successful until we wake up the body. This is the first time we've tried a transfer without two brains involved. If it's not actually Boutin's consciousness in there, the pattern won't take. Even if it is Boutin's consciousness in there, there's no guarantee it will imprint. We've done everything we can to assure a smooth transfer. You've read the reports. But there's still so much involved that we don't know about. We know all the ways it could go right, but not all the ways it could go wrong."

"Do you think it will work or don't you?" Mattson said.

"I think it will work," Wilson said. "But we need to have a healthy respect for all the things we don't know about what we're doing. There's a lot of room for error. Sir."

"Robbins?" Mattson said.

"Lieutenant Wilson's assessment seems right to me, General," Robbins said.

The technicians finished their assessment and reported to General Szilard, who nodded and walked over to Mattson. "The techs say we're ready," Szilard said.

Mattson glanced at Robbins, then Wilson. "Fine," he said. "Let's get this over with."

The Colonial Defense Special Forces build soldiers using a simple recipe: First, start with a human genome. Then subtract .

The human genome comprises roughly twenty thousand genes made from three billion base pairs, spread out over twenty-three chromosomes. Most of the genome is "junk"—portions of the sequence that do not code for anything in the final product of the DNA: a human being. Once nature puts a sequence into DNA it appears reluctant to remove it even if it does nothing at all.