Twin Targets. Jessica Andersen

       Chapter Four

      The flight from Boston to D.C. was a short hop, but even so, John could feel the awful tension in Sydney increasing by the minute.

      He could only imagine what was going on inside her head—the guilt, the fear, the shame, the hope. He could only imagine it because he didn’t have a sibling, didn’t have a strong relationship with his parents…didn’t really have anyone he truly loved, at least on the level other people seemed to feel the emotion. Iceman, indeed.

      He had friends and coworkers, and that was plenty of attachments for him. However, that didn’t mean he was unaware of the lengths other people would go to protect the ones they loved, and the agonies they suffered when those people were hurt, missing…or dead.

      Sydney might have chosen her employer unwisely, and she might’ve let herself be pressured into doing unthinkable things with her scientific knowledge, but that didn’t mean she wasn’t grieving for her sister.

      She sat beside him on the plane, still wearing the borrowed sweats. She had her head tipped back against the seat and her eyes closed as though she’d fallen asleep, but the tension written on her face and in the lines of her hands, which were gripped tightly together in her lap, warned that she wasn’t sleeping. Maybe she was thinking of what she should’ve said or done differently, or maybe she was remembering happier times with her sister.

      “Do you think she’s dead?” she said, surprising him with the first words she’d uttered since they’d boarded.

      “No.”

      She opened one eye and looked over at him. “I’d ask if you were just saying that to make me feel better, but I have a feeling that’s not your thing.”

      “Good guess. I don’t say things I don’t mean, and I don’t like repeating myself.”

      She closed her eyes again, and her face looked a little more relaxed than it had moments before. “You think Tiberius will keep her alive because if she’s dead, he won’t have anything else to threaten me with.”

      Except your own life, John thought. But she’d already committed to that risk when she escaped from the island. “That’s the theory,” he agreed.

      “Which means that I should expect a ransom demand. The password in exchange for her life.”

      “There hadn’t been any contact by the time the plane took off, and the locals were still searching the property and the nearby houses. She might’ve gotten away.” He’d already passed on that update, but repeated the info because he thought it might help her to hear it again.

      The realization brought him up short. He’d not only repeated himself, which he almost never did, but he’d also done it for no other reason than to make Sydney feel better. The very fact had faint warning buzzers going off in the back of his brain.

      Keep it simple, he reminded himself. Keep it in perspective.

      “It’s unlikely she escaped,” she said, her matter-of-factness ruined by the hitch in her voice. “It’s hard for her to get around these days, even in the wheelchair.”

      He heard the hollow ring of guilt, and wondered how much of it was from the immediate situation, and how much was from the fact that the disease had apparently struck one twin and left the other untouched. He imagined there could be a large burden there, and wondered what it might motivate a person to do…like sign on with a killer.

      And perhaps worse?

      He stared at her in repose, trying to gauge what was happening here. His gut told him she’d gone into the job with good intentions. The question was how far would she be willing to go now to reach her goal.

      “I never meant for any of this to happen,” she said without opening her eyes. “Please believe that, if you believe nothing else about me.”

      Because he never said anything he didn’t mean, he didn’t respond to her statement. Instead he said, “Tell me more about the weapon.”

      A faint smile touched her lips and then fled to a frown, as though she was proud of the work, even as she hated what it had become. But when she spoke it was to ask him, “How much do you know about DNA fingerprinting?”

      He’d done a quick info dump while she’d been speaking with her lawyer. “I know the standard fingerprint focuses on twenty places where the human DNA sequence varies in length from one person to the next. Each segment by itself might be the same length in two different people, but it’s statistically impossible—or close enough for government work—for two people to be the same at every one of those segments by random chance. That’s why they use twenty markers, to increase the statistical power of the analysis to the ‘well beyond a shadow of a doubt’ point.”

      She nodded, eyes still closed. “That’s all true, but do you know why those segments vary in length?”

      “Something about repeated letters.” He’d skimmed over the techno-babble, figuring he’d get back to the nitty-gritty if he needed it.

      “Not letters,” she corrected, “dinucleotide repeats. The letters stand for the four nucleotides that make up the DNA molecule: A, C, T and G. They can be combined in all different orders for hundreds or even thousands of bases, and the cellular machinery reads them like a blueprint.” She paused. “Anyway, the segments of DNA used for fingerprinting are essentially stretches of junk DNA—that means they’re not used to encode a protein—made up of the nucleotides C and A, repeated over and over again. They’re different lengths in different people because the repeats let the cellular machinery slip during DNA replication, meaning that a ‘CA’ unit might be added or deleted. As people have evolved over time, the repeats change in length.”

      John more or less got that, but not how it related to her sister. “If the fingerprints are taken from junk DNA, how does a technology aimed at Singer’s syndrome morph into an antifingerprinting weapon?”