Моральный вирусолог

 No doubt? Surely that was pride speaking, his wiliest and most persistent enemy. Every man and woman forever trod the edge of a precipice over the inferno, at risk more than ever of falling to those hungry flames when he or she least believed it possible.

 Shawcross stood and walked over to the woman. Without hesitation, he placed one hand on her ankle. She opened her eyes and sat up, regarding him with amusement, then took hold of his wrist and began to drag his hand along her leg, pressing it hard against the warm, smooth skin.

 Just above the knee, he began to panic - but it wasn't until his fingers struck moisture that he pulled free with a strangled mewling sound, and staggered back to the chair, breathless and shaking.

 That was more like it.

The Shawcross virus was to be a masterful piece of biological clockwork (the likes of which William Paley could never have imagined - and which no godless evolutionist would dare attribute to the "blind watchmaker" of chance). Its single strand of RNA would describe, not one, but four potential organisms.

 Shawcross virus A, SVA, the "anonymous" form, would be highly infectious, but utterly benign. It would reproduce within a variety of host cells in the skin and mucous membranes, without causing the least disruption to normal cellular functions. Its protein coat had been designed so that every exposed site mimicked some portion of a naturally occurring human protein; the immune system, being necessarily blind to these substances (to avoid attacking the body itself), would be equally blind to the invader.

 Small numbers of SVA would make their way into the blood stream, infecting T-lymphocytes, and triggering stage two of the virus's genetic program. A system of enzymes would make RNA copies of hundreds of genes from every chromosome of the host cell's DNA, and these copies would then be incorporated into the virus itself. So, the next generation of the virus would carry with it, in effect, a genetic fingerprint of the host in which it had come into being.

 Shawcross called this second form SVC, the C standing for "customised" (since every individual's unique genetic profile would give rise to a unique strain of SVC), or "celibate" (because, in a celibate person, only SVA and SVC would be present).

 SVC would be able to survive only in blood, semen and vaginal fluids. Like SVA, it would be immunologically invisible, but with an added twist: its choice of camouflage would vary wildly from person to person, so that even if its disguise was imperfect, and antibodies to a dozen (or a hundred, or a thousand) particular strains could be produced, universal vaccination would remain impossible.

 Like SVA, it would not alter the function of its hosts - with one minor exception. When infecting cells in the vaginal mucous membrane, the prostate, or the seminiferous epithelium, it would cause the manufacture and secretion from these cells of several dozen enzymes specifically designed to degrade varieties of rubber. The holes created by a brief exposure would be invisibly small - but from a viral point of view, they'd be enormous.

 Upon reinfecting T-cells, SVC would be capable of making an "informed decision" as to what the next generation would be. Like SVA, it would create a genetic fingerprint of its host cell. It would then compare this with its stored, ancestral copy. If the two fingerprints were identical - proving that the customised strain had remained within the body in which it had begun - its daughters would be, simply, more SVC.

 However, if the fingerprints failed to match, implying that the strain had now crossed into another person's body (and if gender-specific markers showed that the two hosts were not of the same sex), the daughter virus would be a third variety, SVM, containing both fingerprints. The M stood for "monogamous", or "marriage certificate". Shawcross, a great romantic, found it almost unbearably sweet to think of two people's love for each other being expressed in this way, deep down at the subcellular level, and of man and wife, by the very act of making love, signing a contract of faithfulness until death, literally in their own blood.

 SVM would be, externally, much like SVC. Of course, when it infected a T-cell it would check the host's fingerprint against both stored copies, and if either one matched, all would be well, and more SVM would be produced.

 Shawcross called the fourth form of the virus SVD. It could arise in two ways; from SVC directly, when the gender markers implied that a homosexual act had taken place, or from SVM, when the detection of a third genetic fingerprint suggested that the molecular marriage contract had been violated.