“What is the optimum, except the type which can flourish under the widest possible range of conditions? Zachary acquired a female associate, Yukiko Nomura, who influenced his thinking. She may be responsible for the considerable proportion of Mongoloid traits in us. For example, the eyefold is useful in dry, cold, windy climes, and does no harm in others. By way of contrast, a black skin is ideal in the tropics of Terra under primitive conditions, or today on a planet like Nyanza; and it does not prevent its owner from settling in a different environment; but it does require more dietary iodine than a lighter complexion, and iodine shortages are not uncommon in nature. I could go on, but no matter now. And I admit that a number of the choices were arbitrary, perhaps on the basis of personal preference, when some choice had to be made.
“In the end, after years of labor and frequent failure, Zachary and Nomura put together the cell that became ancestral to us. It is not true what a derogatory legend says, that they supplied all the DNA. Their purpose was too grand for vanity. What they gave of their own was that small fraction they knew to be suitable. The rest they got elsewhere, and nearly everything underwent improvement before going into the ultimate cell.
“That cell they then caused to divide into two. For one X chromosome they substituted a Y, thus making the second cell male. They put both in an exogenetic apparatus and nurtured them to term. The infants they adopted, and raised to maturity and their destiny. Those were Izanami and Izanagi, mother and father of the new race.
“Ever afterward, we have guarded our heritage.”
There was a long silence. Man and girl left the street for a road that swung out between trees and estates, toward the western promontory. Patricius declined, its light going tawny. The wind blew cooler, with a tang of salt.
“And you marry only amongst yourselves?” Diana asked finally.
“Yes. We must, or soon cease to be what we are. Permanent union with an outsider means excommunication. M-m—this is not boastfulness, it is realism—we do consider our genes a leaven, which we are glad to provide to deserving members of the general species. You are a rather extraordinary young lady, yourself.”
Her face heated. “And not yet ready for motherhood, thanks!”
“Oh, I would never dream of distressing you.”
She switched the subject back in a hurry. “Doesn’t inbreedin’ make for defective offspring?”
“Not when there are no defects in the parents. As for the inevitable mutations, tests for those are routine, early in pregnancy. You may find our noninvasive DNA-scanning technique interesting. The equipment for it is an export of ours, but protective restrictions on trade have kept it out of the inner Empire. No clinic on Imhotep has felt it could afford the cost.”
Diana grimaced. “And any embryo that isn’t ‘perfect’ you—terminate, is that the nice word?”
“As a matter of fact, seldom; only if the prospects for a satisfying life are nil. True, the mother usually elects to have the zygote removed. But it’s brought to term externally … or in the womb of an ordinary Daedalan volunteer. We always find couples eager to adopt such a baby. Remember, it’s not born with any serious handicap; as a rule, nothing undesirable is evident at all. It’s still a superior human being. It is simply not a Zacharian.”
“Well, that’s better.” Diana shook her head and sighed. “You’re right, this is an almighty peculiar place. How’d it get started, anyway?”
Kukulkan scowled. “What the Founders did not foresee was the effect of an unpleasant characteristic of the species; and before you point this out yourself, I concede that Zacharians aren’t free of it either. Perhaps, if we had had the upper hand, we would have developed into an oppressive master caste. As it was, we were a tiny minority, inevitably but annoyingly exclusive. Astarte Zachary, let us say, might be a loyal shipmate of Pierre Smith; she might take him for a lover; but never would she consider marrying him, or his brother, or anybody except a fellow Zacharian. The reasons were plain, and they were … humiliating. The ordinaries retaliated, more and more, with exclusionism of their own. Here and there, discrimination turned into outright persecution. ‘Incest’ was almost the least ugly of the words thrown at us. The collapse of the Polesotechnic League removed the last barrier against intolerance—not individual intolerance, which we could deal with, but institutionalized intolerance, discriminatory laws in society after society. Many among us found it easier to give up the struggle and merge into the commonality. The need for a homeland became ever more clear.