The Best From Fantasy & Science Fiction Part 11

ISAAC ASIMOV

On December 12, 1968, I gave a talk to a meeting of doctors and lawyers in San Jose, California.[ Those of my Gentle Readers who know that under no circ.u.mstances will I take a plane need not register shock. I traveled to California and back by train. -Yea, they still run.]

Naturally, I was asked to speak on some subject that would interest both groups. Some instinct told me that medical malpractice suits might interest both but would nevertheless not be a useful topic. I spoke on genetic engineering instead, therefore, and, toward the end, discussed the matter of cloning.

In the audience was my good friend of three decades-the well-known science fiction writer, bon vivant, and wit, Randall Garrett Out of the corner of my eye, I noticed a piece of paper placed on the podium as I talked about cloning. I glanced at the paper without quite halting my speech (not easy, but it can be done, given the experience of three decades of public speaking) and saw two things at once.

First, it was one of Randall's superlative pieces of satiric verse, and second, it was clearly intended to be sung to the tune of "Home on the Range."

Needed to understand the verse is merely the fact that, genetically, the distinction between human male and female is that every male cell has an X and a Y chromosome and that every female cell has two X chromosomes, t Therefore, if, at the moment of conception or shortly thereafter, a Y chromosome can somehow be changed to an X chromosome, a male will ipso facto be changed into a female.

Here, then, is "Randall's Song," to which I took the liberty of adding a verse myself: (1st verse) O, give me a clone Of my own flesh and bone With its Y chromosome changed to X; And when it is grown Then my own little clone Will be of the opposite s.e.x.

(chorus) Clone, clone of my own, With its Y chromosome changed to X; And when I'm alone With my own little clone We will both think of nothing but s.e.x.

(2nd verse) O, give me a clone, Hear my sorrowful moan, Just a clone that is wholly my own; And if it's an X Of the feminine s.e.x O, what fun we will have when we're p.r.o.ne.

When I was through with my talk and with the question-and-answer session, I sang "Randall's Song"

in my most resonant baritone and absolutely brought the house down.

Three and a half weeks later I sang it again at the annual banquet of the Baker Street Irregulars, that fine group of Sherlock Holmes fanciers, adjusting it slightly to its new task (O, give me some clones / Of the great Sherlock Holmes / With their Y chromosome) and brought the house down again. But you may, by now, be asking yourself, "What's a clone?" It's been in the news a great deal lately, but recognizing a word and knowing what it represents can be two different things. So let's go into the matter-The word "clone" is Greek, exactly as it stands, provided you spell it in Greek letters, and it means "twig." [See "Counting Chromosomes," F&SF, June 1968.]

A clone is any organism (or group of organisms) that arises out of a cell (or group of cells) by meansother than s.e.xual reproduction. Put it another way: It is an organism that is the product of as.e.xual reproduction. Put it still another way: It is an organism with a single parent, whereas an organism that arises from s.e.xual reproduction (except where self-fertilization is possible) has two parents.

As.e.xual reproduction is a matter of course among one-celled organisms (though s.e.xual reproduction can also take place), and it is also very common in the plant world.

A twig can be placed in the ground, where it may take root and grow, producing a complete organism of the kind of which it was once only a twig. Or the twig can be grafted to the branch of another tree (of a different variety even), where it can grow and flourish. In either case, it is an organism with a single parent, and s.e.x has had nothing to do with its making. It is because human beings first encountered this as.e.xual form of reproduction, hi connection with fruit trees probably, that such a one-parent organism of non-s.e.xual origin is called a "twig"; that is, "clone."

And what of multicellular animals?

As.e.xual reproduction can take place among them as well. The more primitive the animal-that is, the less diversified and specialized its cells are-the more likely it is that as.e.xual reproduction can take place.

A sponge, or a freshwater hydra, or a flatworm, or a starfish can, any of them, be torn into parts and these parts, if kept in their usual environment, will each grow into a complete organism. The new organisms are clones.

Even organisms as complex as insects can in some cases give birth to parthenogenetic young and, in the case of aphids, for instance, do so as a matter of course. In these cases, an egg cell, containing only a half set of chromosomes, does not require union with a sperm cell to supply the other half set. Instead, the egg cell's half set merely duplicates itself, producing a full set, all from the female parent, and the egg then proceeds to divide and become an independent organism, again a kind of clone.

In general, though, complex animals and, in particular, vertebrates do not clone but engage in s.e.xual reproduction exclusively.

Why?-Two reasons.

In the first place, as an organism becomes more complex and specialized, its organs, tissues, and cells become more complex and specialized as well. The cells are so well adapted to perform their highly specialized functions, that they can no longer divide and differentiate as the original egg cells did. [This is not mysterious. We see an a.n.a.logy on the social plane. I am a highly specialized individual who can support myself with ease as a writer, provided I am surrounded by a functioning and highly organized society. Place me on a desert island and I shall quickly perish since I don't know the first thing about the simplest requirements for self-support.]

This seems a terrible disadvantage. Organisms that can clone, reproducing themselves as.e.xually, would seem to be much better off than other organisms-who must go to the trouble of finding partners and who must engage in all the complex phenomena, both physical and chemical, involved in s.e.xual reproduction. Think of all the human beings who, for one slight flaw or another, can't have children -a problem that would be unknown if we could just release a toe and have it grow into another individual while we grew another toe.

Here comes the second reason, then. There's an evolutionary advantage to s.e.xual reproduction that more than makes up for all the inconveniences. In cloning, the genetic contents of new organisms remain identical with those of the original organisms, except for occasional mutations. If the organism is very efficiently adapted to its surroundings, this is useful, but it is an extremely conservative mechanism that reduces the chance of change. Any alteration in the environment could quickly lead to the extinction of a species.

In short, a s.e.xually reproducing species evolves much more quickly than a cloning species, and such difficult-to-evolve specializations as intelligence are not likely to arise in the entire lifetime of a habitable planet, without s.e.xual reproduction.

Yet in one specialized way cloning can take place in even the most advanced animals-even in the human being.

Consider a human egg cell, fertilized by a human sperm cell. We now have a fertilized egg cell which contains a half set of genes from its mother and a half set from its father.This fertilized egg cell cannot become an independently living organism for some nine months, for it must divide and redivide within its mother's womb and be nourished by way of its mother's bloodstream.

It must develop, specialize, and grow larger until it has developed the necessary ability to live independently. Even after it emerges from its mother's womb, it requires constant and unremitting care for a period of time before it can be trusted to care for itself.

Nevertheless, the matter of necessary care is genetically irrelevant The fertilized egg is already a separate organism with its genetic characteristics fixed and unique.

The first step in the development of the fertilized egg is that it divides into two cells that cling together.

Each of these two cells divides again, and each of the four that results divides again and so on.

If, after the first cell division, the two offspring cells, for any reason, should happen to fall apart, each offspring cell may then go on to develop into a complete organism of its own. The result is a pair of identical twins, each with the same genetic equipment and each of the same s.e.x, of course. In a sense, each twin is a clone of the other.

There is no reason to suppose that this separation of offspring cells can't happen over and over, so that three or four or any number of organisms might not develop from the original fertilized egg. As a matter of practical fact, however, a mother's womb can only hold so much, and if there are multiple organisms developing, each is sure to be smaller than a single organism. The more organisms that develop, the smaller each one and, in the end, they will be too small to survive after delivery.

There are such things as identical triplets and quadruplets, but I doubt that any higher number of infants would survive long after birth without the advantages of modern medical technique. Even then it is hard enough.

Identical twins are very like each other and often display mirror-image characteristics. (I once had a chemistry professor with his nose canted to the left. His identical-twin brother had his nose canted to the right, I was told.) It is also possible, however, though not usual, for a woman to bring two different egg cells to fruition at the same time. If both are fertilized, two children will be born who are each possessed of genetic equipment different from the other. What results are "fraternal twins" who need not be of the same s.e.x and who need not resemble each other any more than siblings usually do.

Consider the fertilized egg again. Every time it divides and redivides, the new cells that form inherit the same genetic equipment possessed by the original fertilized egg.

Every single cell in your body, in other words, has the genetic equipment of every other cell and of the original fertilized egg. Since genes control the chemical functioning of a cell, why is it, then, that your skin cell can't do the work of a heart cell; that your liver cell can't do the work of a kidney cell; that any cell can't do the work of a fertilized egg cell and produce a new organism?

The answer is that though all the genes are there in every cell of your body, they aren't all working alike. The cell is an intricate a.s.semblage of chemical reactions, chemical building blocks, chemical products, and physical structures, all of which influence one another. Some genes are inhibited and some are stimulated, in a variety of ways depending on subtle factors, with the result that different cells in your body have genetic equipment in which only characteristic parts are working at characteristic rates.

Such specialized development begins in the earliest embryo, as some cells come into being on the outside of the embryo, some on the inside; some with more of the original yolk, some with less; some with first chance at absorbing nutrients from the maternal bloodstream, some with only a later chance.

The details are clearly of the greatest importance to human biology, and biologists just don't yet know them.

Naturally, the ordinary "somatic cells" of an adult human body, with their genetic equipment working only in highly specialized ways, cannot divide into a whole organism if left to themselves. Many body cells, such as those of the muscles or nerves, have become so specialized they can't divide at all. Only the s.e.x cells, eggs and sperm, retain the lack of genetic specialization required to produce a new organism under the proper circ.u.mstances.

Is there any way of unspecializing the genetic structure of somatic cells so as to allow them to develop into a new organism?Well, the genes are contained in the nucleus of the cell, which makes up a small portion of the total and is marked off by a membrane of its own. Outside the nucleus is the cytoplasm of a cell, and it is the material in the cytoplasm that provides the various chemicals that help serve to inhibit or stimulate e action of the genes.

Suppose, then, the nucleus of a somatic cell were surrounded with the cytoplasm of an egg cell.

Would the genetic equipment in the nucleus unblock, and would the egg cell then proceed to divide and redivide? Would it go on to form an individual with the genetic equipment of the original somatic cell and, therefore, of the person from whom the somatic cell was taken? If so, the new organism would be a clone of the person who donated the somatic cell.

The technique has been tried on different animals. You begin with an unfertilized egg cell and treat it in such a way as to remove its nucleus, either by delicately cutting it out or by using some chemical process. In the place of the removed egg cell nucleus, you insert the nucleus of a somatic cell of the same (or, possibly, an allied) species, and then let nature take its course.

This has been successfully tried with animals as complex as a tadpole.

It stops being easy after the frog, though. Frog eggs are naked and can be manipulated easily. They develop in water and can just lie there after the micro-operation.

The eggs of reptiles and birds, however, are enclosed in sh.e.l.ls, which adds to the technical difficulty.

The eggs of mammals are very small, very delicate, very easily damaged. Furthermore, even if a mammalian egg has had its nucleus replaced, it would then have to be implanted into the womb of a female and allowed to come to term there.

The practical problems of mammalian cloning are such that there is no chance of its happening for some time yet. Yet biologists are anxious to perform the feat and are trying hard. Eventually, they will no doubt succeed. What purpose will it serve?

If clones can be produced wholesale, a biologist can have a whole group of animals with identical genetic equipment; a set of ten thousand identical-twin mice, let us say. There are many animal experiments that can be conducted with the hope of more useful results if the question of genetic variation could be eliminated.

By the addition of other genetic-engineering techniques, it might be possible to produce a whole series of animals with identical genetic equipment, except that in each case, one gene is removed or altered-a different gene in each individual perhaps. The science of genetics would then advance in seven-league strides.

There would be practical uses, too. A prize bull or a champion egg-laying hen could be cloned, and the genetic characteristics that make the record-breaking aspects of the animal possible would be preserved without the chance of diminution by the interplay of genes obtained from a second parent.

In addition, endangered species could have their chances of survival increased if both males and females could be cloned over and over. When the number of individuals was sufficiently increased, s.e.xual reproduction could be allowed to take over.

We might even dream of finding a frozen mammoth with some cell nuclei not entirely dead. We might then clone one by way of an elephant's womb. If we could find a male and a female mammoth- To be sure, if cloning is overdone, the evolutionary advantage of s.e.xual reproduction is to some extent neutralized, and we might end up with a species in which genetic variability is too narrow for long-term survival.

It is important to remember that the most important genetic possession of any species is not this gene or that, but the whole mixed bag. The greater the variety of genes available to a species, the more secure it is against the vicissitudes of fortune. The existence of congenital disorders and gene deficiencies is the price paid for the advantage of variety and versatility.

And what about cloned human beings, which is, after all, the subject matter of "Randall's Song"?

These may never be as important as you think. The prospect of importance rests chiefly on certain misapprehensions on the part of the public. Some people, for instance, pant for clones because they think them the gateway to personal immortality. That is quite wrong.

Your clone is not you. Your clone is your twin brother (or sister) and is no more you than yourordinary identical twin would be. Your clone does not have your consciousness, and if you die, you are dead. You do not live on in your clone. Once that is understood, I suspect that much of the interest in clones will disappear.

Some people fear clones, on the other hand, because they imagine that morons will be cloned in order to make it possible to build up a great army of cannon fodder that despots will use for world conquest.

Why bother? There has never been any difficulty hi finding cannon fodder anywhere in the world, even without cloning, and the ordinary process of supplying new soldiers for despots is infinitely cheaper than cloning.

More reasonably, it could be argued that the clone of a great human being would retain his genetic equipment and, therefore, would be another great human being of the same kind. In that case, the chief use of cloning would be to reproduce genius.

That, I think, would be a waste of time. We are not necessarily going to breed thousands of transcendent geniuses out of an Einstein or thousands of diabolical villains out of a Hitler.

After all, a human being is more than his genes. Your clone is the result of your nucleus being placed into a foreign egg cell and the foreign cytoplasm in that egg cell will surely have an effect on the development of the clone. The egg will have to be implanted into a foreign womb and that, too, will have an influence on the development of the organism.

Even if a woman were to have one of her somatic nuclei implanted into one of her own egg cells and if she were then to have the egg cell implanted into me womb of her own mother (who, we will a.s.sume, is still capable of bearing a child), the new organism will be born into different circ.u.mstances and that would have an effect on its personality, too.

For instance, suppose you wanted one hundred Isaac Asimovs so that the supply of F&SF essays would never run out. You would then have to ask what it was that made me the kind of writer I am or a writer at all. Was it only my genes?

I was brought op in a candy store under a father of the old school who, although he was Jewish, was the living embodiment of the Protestant ethic. My nose was kept to the grindstone until I could no longer remove it Furthermore, I was brought up during the Great Depression and had to find a way of making a living-or I would inherit the candy store, which I desperately didn't want to do. Furthermore, I lived in a time when science fiction magazines, and pulp magazines generally, were going strong, and when a young man could sell clumsily written stories because the demand was greater than the supply.

Put it all together, they spell M-E.

The Isaac Asimov clones, once they grow op, simply won't live in the same social environment I did, won't be subjected to the same pressures, won't have the same opportunities. What's more, when I wrote, I just wrote-no one expected anything particular from me. When my clones write, their products will always be compared to the Grand Original and that would discourage and wipe out anyone.

The end result will be that though my clones, or some of them, might turn out to be valuable citizens of one kind or another, it would be very unlikely that any one of them would be another Isaac Asimov, and their production would not be worthwhile. Whatever good they might do would not be worth the reduction they would represent in the total gene variability of humanity.

Yet cloning would not be totally useless, either. There would be the purely theoretical advantage of studying the development of embryos with known variations in their genes which, except for those variations, would have identical genetic equipment (This would raise serious ethical questions, as all human experimentation does, but that is not the issue at the moment) Then, too, suppose it were possible to learn enough about human embryonic development to guide embryos into all sorts of specialized bypaths that would produce a kind of monster that had a full-sized heart, with all else vestigial, or a full-sized kidney or lung or liver or leg. With just one organ developing, techniques of forced growth (in the laboratory, of course, and not in a human womb) might make development to full size a matter of months only.

We can therefore imagine that at birth, every human individual will have sc.r.a.pings taken from his little toe, thus attaining a few hundred living cells that can be at once frozen for possible eventual use. (This isdone at birth, because the younger the cell, the more efficiently it is likely to clone.) These cells could serve as potential organ banks for the future. H the time were to come when an adult found he had a limping heart or fading pancreas or whatever, or if a leg had been lost in an accident or had had to be amputated, then those long-frozen cells would be defrosted and put into action.

An organ replacement would be grown and since it would have precisely the same genetic equipment as the old, the body would not reject it -Surely that is the best possible application of cloning.

John Varley's first story for F&Sf was "Picnic on Nearside" in 1974. Since then, he has earned a reputation as one of sf's most exciting new storytellers through such work as "Retrograde Summer," "The Black Hole Pa.s.ses," "In the Bowl" (Best from F&SF, 22nd series) and his first novel, t.i.tan. This story was another Nebula award nominee.

In the Hall of the Martian Kings

JOHN VARLEY.

It took perseverance, alertness, and a willingness to break the rules to watch the sunrise in Tharsis Canyon. Matthew Crawford s.h.i.+vered in the dark, his suit heater turned to emergency setting, his eyes trained toward the east. He knew he had to be watchful. Yesterday he had missed it entirely, s.n.a.t.c.hed away from him in the middle of a long, unavoidable yawn. His jaw muscles stretched, but he controlled it and kept his eyes firmly open.

And there it was. Like the lights in a theater after the show is over: just a quick brightening, a splash of localized bluish-purple over the canyon rim, and he was surrounded by footlights. Day had come, the truncated Martian day that would never touch the blackness over his head.

This day, like the nine before it, illuminated a Tharsis radically changed from what it had been over the last sleepy ten thousand years. Wind erosion of rocks can create an infinity of shapes, but it never gets around to carving out a straight line or a perfect arc. The human encampment below him broke up the jagged lines of the rocks with regular angles and curves.

The camp was anything but orderly. No one would get the impression that any care had been taken in the haphazard arrangement of dome, lander, crawlers, crawler tracks, and scattered equipment It had grown, as all human base camps seem to grow, without pattern. He was reminded of the footprints around Tranquillity Base, though on a much larger scale.

Tharsis Base sat on a wide ledge about halfway up from the uneven bottom of the Tharsis arm of the Great Rift Valley. The site had been chosen because it was a smooth area, allowing easy access up a gentle slope to the flat plains of the Tharsis Plateau, while at the same time only a kilometer from the valley floor. No one could agree which area was most worthy of study: plains or canyon. So this site had been chosen as a compromise. What it meant was that the exploring parties had to either climb up or go down, because there wasn't a d.a.m.n thing worth seeing near the camp. Even the exposed layering and its areological records could not be seen without a half-kilometer crawler ride up to the point where Crawford had climbed to watch the sunrise.

He examined the dome as he walked back to camp. There was a figure hazily visible through the plastic. At this distance he would have been unable to tell who it was if it weren't for the black face. He saw her step up to the dome wall and wipe a clear circle to look through. She spotted his bright red suit and pointed at him. She was suited except for her helmet, which contained her radio. He knew he was in trouble. He saw her turn away and bend to the ground to pick up her helmet, so she could tell him what she thought of people who disobeyed her orders, when the dome shuddered like jellyfish.

An alarm started in his helmet, flat and strangely soothing coming from the tiny speaker. He stood there for a moment as a perfect smoke ring of dust billowed up around the rim of the dome. Then he was running.

He watched the disaster unfold before his eyes, silent except for the rhythmic beat of the alarm bell inhis ears. The dome was dancing and straining, trying to fly. The floor heaved up in the center, throwing the black woman to her knees. In another second the ulterior was a whirling snowstorm. He skidded on the sand and fell forward, got up in time to see the fibergla.s.s ropes on the side nearest him snap free from the steel spikes anchoring the dome to the rock. The dome now looked like some fantastic Christmas ornament, filled with snowflakes and the flas.h.i.+ng red and blue lights of the emergency alarms. The top of the dome heaved over away from him, and the floor raised itself high in the air, held down by the unbroken anchors on the side farthest from him. There was a gush of snow and dust; then the floor settled slowly back to the ground. There was no motion now but the leisurely folding of the depressurized dome roof as it settled over the structures inside.

The crawler skidded to a stop, nearly rolling over, beside the deflated dome. Two pressure-suited figures got out. They started for the dome, hesitantly, in fits and starts. One grabbed the other's arm and pointed to the lander. The two of them changed course and scrambled up the rope ladder hanging over the side.

Crawford was the only one to look up when the lock started cycling. The two people almost tumbled over each other coming out of the lock. They wanted to do something, and quickly, but didn't know what. In the end, they just stood there silently twisting their hands and looking at the floor. One of them took off her helmet. She was a large woman, in her thirties, with red hair shorn off close to the scalp.

"Matt, we got here as ..." She stopped, realizing how obvious it was. "How's Lou?"

"Lou's not going to make it." He gestured to the bunk where a heavyset man lay breathing raggedly into a clear plastic mask. He was on pure oxygen. There was blood seeping from his ears and nose.

"Brain damage?"

Crawford nodded. He looked around at the other occupants of the room. There was the Surface Mission Commander, Mary Lang, the black woman he had seen inside the dome just before the blowout She was sitting on the edge of Lou Prager's cot, her head cradled in her hands. In a way, she was a more shocking sight than Lou. No one who knew her would have thought she could be brought to this limp state of apathy. She had not moved for the last hour.

Sitting on the floor huddled in a blanket was Martin Ralston, the chemist His s.h.i.+rt was b.l.o.o.d.y, and there was dried blood all over his face and hands from the nosebleed he'd only recently gotten under control, bat his eyes were alert He s.h.i.+vered, looking from Lang, his t.i.tular leader, to Crawford, the only one who seemed calm enough to deal with anything. He was a follower, reliable but unimaginative.

Crawford looked back to the newest arrivals. They were Lucy Stone McKillian, the red-headed ecologjst, and Song Sue Lee, the exo-biologist They still stood numbly by the airlock, unable as yet to come to grips with the fact of fifteen dead men and women beneath the dome outside.

"What do they say on the Burroughs?" McKillian asked, tossing her helmet on the floor and squatting tiredly against the wall. The lander was not the most comfortable place to hold a meeting; all the couches were mounted horizontally since their purpose was cus.h.i.+oning the acceleration of landing and takeoff.

With the s.h.i.+p sitting on its tail, this made ninety per cent of the s.p.a.ce in the lander useless. They were all gathered on the circular bulkhead at the rear of the lifesystem, just forward of the fuel tank.

"We're waiting for a reply," Crawford said. "But I can sum op what they're going to say: not good.