Frameshift

While he waited for the grad students to report back on the samples Helen Kawabata had provided, Pierre mapped out all the cytosines in the portion of Molly’s DNA that contained the code for the telepathy neurotransmitter. He then crunched the numbers backward and forward, looking for a pattern. He’d wanted to crack the hypothesized code that cytosine methylation represented, and he could think of no more interesting stretch of DNA to work on than that part of Molly’s chromosome thirteen.

And at last he succeeded.

It was incredible. But if he could verify it, if he could prove it empirically—$

It would change everything.

According to his model, cytosine-methylation states provided a checksum — a mathematical test for whether the string of DNA had been copied exactly. It tolerated errors in some parts of the DNA strand (although those errors tended to render the DNA garbled and useless, anyway), but in others — notably right around the telepathy frameshift — it would allow no errors, invoking some sort of enzymatic correction mechanism as soon as copying was initiated. The cytosine-methylation checksum served almost as a guardian. The code to synthesize the special neurotransmitter was there, all right, but it was deactivated, and almost any attempt to activate it was reversed the first time the DNA was copied.

Pierre stared out the lab window, contemplating it all.

If a frameshift in a protected region occurred by accident due to a random addition or loss of a base pair from the chromosome, the cytosine-methylation checksum saw to it that any future copies — including those used in eggs or sperm — were corrected, preventing the error in coding from being passed on to the next generation. Molly’s parents had not been telepaths, nor was her sister, nor would any of her children be.

Pierre understood what it meant, but was still shocked. The implications were staggering: a built-in mechanism existed to correct frameshifts, a built-in way of keeping certain fully functional bits of the genetic code from becoming active.

Somehow, the enzymatic regulator had failed to work during the development of Molly’s own body. Perhaps that had been due to some drug — prescription or illegal — Molly’s mother had been using while pregnant with Molly, or to some nutrient missing from Molly’s mother’s diet. There were so many variables, and it was so long ago, that it would likely be impossible to duplicate the biochemical conditions under which Molly had developed between her conception and birth. But whatever had happened then had allowed the expression of something that was — the anthropomorphic language kept springing to Pierre’s mind, despite his efforts to avoid it — that was designed to remain hidden.

A Saturday afternoon in June. The doorbell rang.

“Who could that be?” said Pierre to little Amanda, who was sitting in his lap. “Who could that be?” He made his voice high and soft, the exaggerated tones generations of parents have used when talking to their babies. Meanwhile, Molly got up and went to the door. She checked the peephole, then opened the door, revealing Ingrid and Sven Lagerkvist, and their little boy, Erik.

“Look who’s here!” said Pierre, still baby-talking to Amanda. “Why, look who’s here! It’s Erik. See, it’s Erik.”

Amanda smiled.

Sven was carrying a large wrapped gift. He kissed Molly on the cheek, handed the gift to her, and came into the living room.

Molly placed the package on the pine coffee table. She then came over to Pierre and took Amanda from him. Although Pierre loved holding his daughter in his arms while sitting in a chair, he’d given up walking and carrying her after almost dropping her a few weeks before.

Molly carried Amanda into the middle of the room and set her down on the carpet near the coffee table. Sven, holding Erik’s chubby little hand, led him across the living room to where Amanda was.

“Manda,” said Erik in his soft, slurred way. As was typical of those with Down’s syndrome, Erik’s tongue stuck partway out of his mouth when he wasn’t speaking.

Amanda smiled and made a small sound low in her throat.

Pierre leaned back in his chair. He hated that sound, that little thrumming. Each time Amanda made it, his heart skipped. Maybe this time — maybe at last…

Molly pointed at the brightly wrapped box and spoke to Amanda. “Look what Erik and Uncle Sven and Aunt Ingrid brought for you,” she said.

“Look! A present for the birthday girl.” She turned to the adult Lagerkvists. “Thanks so much, guys. We really appreciate you coming over.”

“Oh, it’s our pleasure,” said Ingrid. She was wearing her red hair loose about her shoulders. “Erik and Amanda always seem to have such a good time together.”

Pierre looked away. Erik was two; Amanda was one. Normally, they wouldn’t have made good playmates, but Erik’s Down’s syndrome had already held up his mental development enough that he really was at much the same stage as Amanda.