Free Mutant by Peter Clement

single strands. Afterward, we lowered the temperature to fifty-five degrees centigrade and added the primers, letting this mix stand for sixty seconds. . . .”
    Sounds of a dozen chairs scraping and people noisily clearing their throats quickly filled the room as his audience expressed their disinterest in the technical detail. Continuing to talk, Azrhan gave desperate little glances toward his supervisor that begged for a rescue.
    “Just like making soup,” broke in Sullivan. “In fact I could cook up a batch of the stuff in my kitchen if the oven timer weren’t broken.” There were a few isolated chuckles, but the restlessness persisted. “In the lab it’s even easier, because we have a machine the size of a double microwave to do all this finicky business for us, so let’s give that part a pass.”
    “Thank God!” someone muttered gratefully.
    “Because what comes now is the secret ingredient,” she continued, lowering her voice and drawing them to her, “an enzyme called Taq polymerase.”
    “Taq what?” exclaimed a man taking notes two seats away.
    “Taq polymerase,” she said lightly, as if to imply everyone should be familiar with the term. “Marine biologists first discovered this reagent decades ago, in the bacteria which thrive amidst the scalding waters of thermal vents at the ocean floor. The substance’s job is to set in motion the process that replicates DNA in these microbes, the same role all polymerases play in plants and animals throughout the planet. But a man named Kary Mullis realized that, unlike the others, this polymerase could function at the high temperatures we need to uncoil and mark specific segments of DNA with primers, as Azrhan so eloquently described. In 1993 Mullis received the Nobel Prize for using this observation to develop the polymerase chain reaction, or PCR— the technique used today to multiply a specific portion of a DNA strand starting from just a few molecules. Since that discovery, mankind’s study of DNA became infinitely easier, our unlocking the human genome is proceeding faster than anyone expected, and our ability to free the innocent or convict the guilty from evidence based on a microscopic drop of blood or semen has changed justice forever.” She paused to let what she’d said sink in so she wouldn’t overwhelm them with what came next.
    “Dr. Sullivan, cut to the chase. What did you find?” demanded the woman from
Environment Watch
, her tone a splash of acid against the eardrum.
    To Sullivan’s surprise, Azrhan, who had sunk into his seat when she first started talking, now leaped to his feet and, taking a deep breath as if to steel himself, took over the press conference again. “Our machine nudged the temperature up to seventy-five degrees centigrade, added the Taq polymerase, and stirred in a good supply of nucleotides—the basic building blocks of DNA. Normally this would start the reaction we were after, if the cauliflower mosaic virus was present. For those of you who are interested, Taq polymerase moves up and down the DNA strand to be replicated and, using it as a template, brings in the appropriate nucleotides, stringing them together in the right order. The result is a new strand of DNA complementary to the original. But as Mullis discovered, it can only set up on the strand to be copied at the points where that strand has a primer on it.” His voice confident, his delivery assured, and his eyes sparkling with enthusiasm for the work he obviously loved, he recaptured everyone’s attention. “In other words, since our primers were specific to cauliflower mosaic virus, if replication occurred at all, we’d have our proof that a naked DNA vector successfully infiltrated the flora on the grounds at Agrenomics. Furthermore, passing these copied bits and pieces of CaMV genes through an electrophoretic gel would sort them out according to molecular weight, thereby offering up that intruder’s genetic fingerprint.” He abruptly retook