John Scalzi - The Ghost Brigades

Special Forces scientists are not nearly so precious. With each new body model they build, their first step is to strip out the redundant and switched-off genetic matter. What is left is a lean, mean, streamlined DNA sequence that is completely useless; editing the human genome destroys its chromosomal structure, leaving it unable to reproduce. But this is just a first step. Reassembling and replicating the new genome is several steps away.

The new, small DNA sequence features every gene that makes a human what he or she is, and this simply is not good enough. The human genotype does not allow the human phenotype the plasticity the Special Forces require, which is to say: Our genes can't make the superhumans Special Forces soldiers need to be. What is left of the human genome is now rent apart, redesigned and reassembled to build the genes that will code for substantially enhanced abilities. This process can require the introduction of additional genes or genetic material. The genes that come from other humans usually present little problem with their incorporation, since the human genome is fundamentally designed to accommodate genetic information from other human genomes (the process by which this is usually, naturally and enthusiastically accomplished also relatively easy to incorporate, seeing as all life on Earth features the same genetic building blocks and are related to each other genetically.

Incorporating genetic material from non-terrestrial species is substantially more difficult. Some planets evolved genetic structures roughly similar to Earth's, incorporating some if not all the nucleotides involved in terrestrial genetics (perhaps not coincidentally, the intelligent species of these planets have been known to consume humans from time to time; the Rraey, for example, found humans quite tasty). But most alien species have genetic structures and components wildly different from terrestrial creatures. Using their genes is not a simple matter of cutting and pasting.

Special Forces solved this problem by reading the DNA equivalent of the alien species into a compiler that then spat out a genetic "translation" in terrestrial DNA format—the resulting DNA, if allowed to develop, would create an entity as close to the original alien creature in appearance and function as it was possible to get. Genes from the transliterated creatures were then wrought into the Special Forces DNA.

The end result of this genetic designing was DNA that described a creature based on a human, but not a human at all— inhuman enough that the creature, if allowed to develop from this step, would be an unholy agglomeration of parts, a monstrous creature that would have sent its spiritual godmother Mary Wollstonecraft Shelley far around the bend. Having pulled the DNA so far from humanity, Special Forces scientists now sculpted the genetic message to jam the creature they were forming back into a recognizably human shape. Among themselves the scientists brooded that this was the most difficult step; some (quietly) questioned its utility. None of them, it should be noted, looked any less than human themselves.

The DNA, sculpted to offer its owner superhuman abilities in human shape, is now finally assembled. Even with the addition of non-native genes, it is substantially leaner than the original human DNA; supplemental coding causes the DNA to organize into five chromosomal pairs, down substantially from an unaltered humans twenty-three and only one more than a fruit fly. While Special Forces soldiers are provided the sex of their donor and genes related to sexual development are preserved in the final genetic reduction, there is no Y-chromosome, a fact that made the earliest Special Forces-assigned scientists (the male ones) vaguely uncomfortable.

The DNA, now assembled, is deposited into a vacant zygote shell, which is itself placed into a developmental creche, and the zygote gently prodded into mitotic division. The transformation from zygote to full-fledged embryo proceeds at a profoundly accelerated rate, producing metabolic heat levels that come close to denaturing the DNA. The developmental creche fills with heat-transferring fluid packed with nanobots, which saturate the developing cells and act as heat sinks for the rapidly growing embryo.

And still Special Forces scientists are not done lowering the percentage of humanity in their soldiers. After the biological overhaul come the technological upgrades. Specialized nanobots injected into the rapidly developing Special Forces embryo head to two destinations. Most head to marrow-rich bone cores, where the nanobots digest the marrow and mechanically breed in its place to create SmartBlood, with better oxygen-carrying capacity than true blood, more efficient clotting and near-immunity to disease. The rest migrate to the fast-expanding brain and lay the groundwork for the BrainPal computer, which when fully constructed will be the size of an aggie marble. This marble, nestled deep in the brain, is surrounded by a dense network of antennae that sample the electric field of the brain, interpreting its wishes and responding through outputs integrated into the soldiers' eyes and ears.

There are other modifications as well, many experimental, tested within a small birthing group to see if they offer any advantages. If they do, these modifications are made more widely available among the Special Forces and hit the list for potential upgrades for the next generation of the Colonial Defense Forces' general infantry. If they don't, the modifications die with their test subjects.

The Special Forces soldier matures to the size of a newborn human in just over twenty-nine days; in sixteen weeks, provided the creche's adequate metabolic management, it has grown to adult size. CDF attempts to shorten the developmental cycle resulted in bodies that fried in their own metabolic heat. Those embryos and bodies that didn't simply abort and die suffered DNA transcription errors, giving rise to developmental cancers and fatal mutations. Sixteen weeks was pushing the edge of DNA chemical stability as it was. At the end of sixteen weeks, the developmental creche sends a synthetic hormone washing through the body, resetting the metabolic levels to normal tolerances.

During development the creche exercises the body to strengthen it and allow its owner to use it from the moment he or she becomes conscious; in the brain, the BrainPal helps develop general neural pathways, stimulate the organs' processing centers, and prepare for the moment its owner was brought to consciousness, to help ease the transition from nothing to something.

For most Special Forces soldiers, all that was left at this point was "birth"—the decanting process followed by the quick and (usually) smooth transition into military life. For one Special Forces soldier, however, there was still one more step to take.

Szilard signaled to his techs, who began their tasks. Wilson focused again on his hardware, and waited for the signal to begin the transfer. The techs gave the all clear; Wilson sent the consciousness on its way. Machinery hummed quietly. The body in the creche remained still. After a few minutes Wilson conferred with the techs, then with Robbins, who came over to Mattson. "It's done," he said.

"That's it?" Mattson said, and glanced over the body in the creche. " He doesn't look any different. He still looks like he's in a coma."

"They haven't woken him up yet," Robbins said. "They want to know how you want to do it. Normally with Special Forces soldiers they wake them up with their BrainPals switched to conscious integration. It gives the soldier a temporary sense of self until he can create one of his own. But since there may already be a consciousness in there, they didn't want to turn that on. It might confuse the person in there."

Mattson snorted; he found the idea amusing. "Wake him up without switching on the BrainPal," he said. "If that's Boutin in there, I don't want him confused. I want him talking."