Mariposa by Greg Bear Page A

psychological disorders—responded positively as well. I altered the focus and expanded the program."
    "So you fix cancer and make people happy, at the same time. How?" Bork asked.
    "The body—the brain—relies on the genome not only for form but for broad patterns of behavior. But genes are not expressed continually. They are controlled by a marvelous system of checks and balances—including overlays to the actual genetic sequences, epigenetic tags or stops that regulate and even prevent certain genes from being expressed. As in a music box, an activated gene sticks up and plays a note, an inactivated gene falls into a gap and is silent.
    "In our childhood and adolescence, tunes emerge and become more or less fixed—the working versions of you and me, better prepared for our environment. However, throughout our lives, our bodies still make changes. As we live, we acquire a few more notes. Our tunes become richer. Little pathways—personality, habits—are worn into our behaviors."
    "What's that got to do with cancer?" Lee asked.
    "Cells too are educated and trained. If they are continually stressed or traumatized—bathed in toxic chemicals, for example—they reach a crisis and a point of decision. Life isn't good. The bargain they made long ago to be part of a larger body isn't working out. So they may try to become independent, paying no attention to the body's needs. Usually the stubbornly independent cells are killed by the immune system. In some cases, they evade destruction, and tumors grow."
    "You're saying we're tumors?" Camp seemed perversely amused.
    "No. Perhaps. I don't know . . . These matters are complicated."
    "What's Mariposa doing to us now?" Bork asked.
    Lee laid his hand on Plover's arm—not in reassurance.
    Plover looked down at the tightening fingers. His brow furrowed. "Stress," he said. "Long-term pressure and pain wear deep, dysfunctional ruts, which become fixed by epigenetic tags in our brains—perhaps in astrocytic cells themselves. We respond with heightened sensitivity to less and less stimulus. Brain and body, working in unison, acquire hair triggers. Our behaviors become inappropriate, erratic. Deep down, we think we are still in whatever situation caused our pain to begin with.
    "Our tune changes for the worse, sometimes drastically. Sour notes, screeches—anxiety, fear. Panic."
    "We weren't in combat for more than a few hours," Nathaniel said.
    "A single major traumatic event—pain, destruction, friends killed, imminent threat to life—mere minutes can cause tremendous stress. The persistent drips and trickles of stress that ordinarily shape our lives and thoughts become a sudden flood. Old patterns are swept away. New channels form, deep and devious. Mariposa works by removing the stops we acquire during traumatic events. The genes are set free from the bad habits they acquired under duress. The world seems less threatening. A kind of balance is restored."
    Plover's face took on that messianic light Nathaniel remembered from his two weeks in Baltimore, in the clinic—when Plover had been the one who had made them feel human again.
    "Balance?" Camp said. "Shit. I'm not in any sort of balance."
    "Your pain went away," Plover asserted, defiant. "You all agreed . . . back then."
    "Not now," Bork said. "I feel like Proteus in his cave—scary. Maybe we can be anything ."
    "I have no idea what I want to be," Lee said.
    "The drug is removing too many controls," Plover said. "We did not see that in animal trials."
    "And that means . . .?" Camp asked.
    "Our talents and abilities are patterned to fit the needs of a larger group. Best for human society . . . But perhaps more control is now being returned to you as individuals. You have become like newborns, in a way. If too many controls are removed—then you either won't feel the need to serve society at all, or you will do so purely on your own terms."
    The table fell quiet. Only Bork and Lee had touched their food. Camp