Nevertheless, the gene for blue eyes may be passed on from generation to generation, unnoticed but unchanged. The potentialities of a race are passed on unchanged-except for mutation-from parent to child. They may be shuffled and dealt and shuffled again, producing an inconceivable number of unique individuals, but the genes are unchanged.
Chess men may be arranged on the board in many combinations, but the unit men do not vary. Fifty-two playing cards may be dealt to produce an enormous number of different hands, but the cards are the original fifty-two. One hand may be full of high cards; another may be worthless -pure chance.
But suppose you were permitted to make up the best hand of five cards possible out of the first ten cards dealt? The chance of getting the best possible hand has been increased two hundred and fifty-two times! (Check it.)
Such is the method of racial improvement by gene selection.
A life-producing cell in the gonads of a male is ready to divide to form gametes. The forty-eight chromosomes intertwine frantically, each with its opposite number. So close is this conjugation that genes or groups of genes may even trade places with their opposites from the other chromosomes. Presently this dance ceases. Each member of a pair of chromosomes withdraws from its partner as far as possible, until there is a cluster of twenty-four chromosomes at each end of the cell. The cell splits, forming two new cells, each with only twenty-four chromosomes, each containing exactly half of the potentialities of the parent cell and parent zygote.
One of these cells contains a chromosome-the X-chromosome-which declares that any zygote formed with its help will be female.
The two cells divide again. But in this fission the chromosomes themselves divide, endwise, thereby conserving every gene and every one of the twenty-four chromosomes. The end product is four wigglers-male gametes, spermatozoa-half of whom can produce females; half, males. The male producers are exactly alike in their gene assortments and are exact complements of the female producers. This is the key point in the technique of gene selection.
The heads of the male producers average four microns in length; the heads of the female producers average five microns in length-another key point.
In the female gonad the evolution of the gamete, or ovum, is like that described for the male gametes, with two exceptions. After the reduction-division in which the number of chromosomes per cell is reduced from forty-eight to twenty-four the result is not two ova, but one ovum and one "polar body." The polar body is a pseudo egg, containing a chromosome pattern complementary to that of the true gamete, but it is sterile. It's a nobody that never will be anybody.
The ovum divides again, throwing off another polar body which has the same pattern as the ovum. The original polar body divides again, producing two more polar bodies of complementary pattern. Thus the polar bodies of pattern complementary to the ovum always exceed in number those of identical pattern. This is a key fact. All ova may become either male or female. Sex of the infant zygote is determined by the cell provided by the father; the mother has no part in it.
The above is a very rough picture. It is necessary to compress, to exaggerate, to omit detail, to use over-simplified analogy. For example, the terms "dominant" and "recessive" are relative terms; and characteristics are rarely determined by one gene alone. Furthermore, mutations-spontaneous changes in the genes themselves-occur with greater frequency than this account has emphasized. But, the picture is reasonably correct in its broad outlines.
How can these facts be used to produce the sort of man or woman one wishes to produce? Offhand, the question appears simple. An adult male produces hundreds of billions of gametes. Ova are produced on no such wholesale scale, but in quite adequate numbers. It would appear to be a simple matter to determine what combination you want and then wait for it to show up... or at least to wait for a combination near enough to be satisfactory.
But it is necessary to recognize the combination wanted when it shows up. And that can be done only by examining the gene patterns in the chromosomes.
Well? We can keep gametes alive outside the body... and genes, while infinitesimally small, are large enough to be recognized under our ultramicroscopes. Go ahead. Take a look. Is it the gamete we want, or is it one of its lesser brothers? If the latter, then reject it, and look again.
Wait a moment! Genes are such tiny things that to examine one is to disturb it. The radiations used to see a gamete closely enough to tell anything about its chromosomes will produce a storm of mutations. Sorry, what you were looking for isn't there any more. You've changed it-more probably killed it. So we fall back on the most subtle and powerful tool of research... inference. You will remember that a single male gonad cell produces two groups of gametes, complementary in their chromosome patterns. The female producers have the larger heads; the males are more agile. We can separate them. If, in a given small constellation of male gametes, enough members are examined to determine that they all stem from the same parent cell, then we may examine in minute detail the group producing the sex we do not want. From the chromosome-gene pattern of the group examined we can infer the complementary pattern of the group kept free of the perils of examination.
With female gametes the problem is similar. The ovum need not leave its natural environment in the body of the female. The polar bodies, worthless and non-viable in themselves, are examined. Their patterns are either identical with that of their sister cell, or complementary. Those that are complementary are more numerous than those identical. The pattern of the ovum may be inferred with exactness.
Half the cards are face up. Therefore we know the value of the cards face down. We can bet-or wait for a better hand. Romantic writers of the first days of genetics dreamed of many fantastic possibilities-test-tube babies, monsters formed by artificial mutation, fatherless babies, babies assembled piece by bit from a hundred different parents. All these horrors are possible, as the geneticists of the Great Khans proved, but we citizens of this Republic have rejected such tampering with our life stream. Infants born with the assistance of the neo-Ortega-Martin gene selection technique are normal babies, stemming from normal germ plasm, born of normal women, in the usual fashion.
They differ in one respect only from their racial predecessors: they are the best babies their parents can produce!
CHAPTER FOUR
Boy Meets Girl
MONROE-ALPHA called for his ortho-wife again the next evening. She looked up and smiled as he came into her apartment. "Two nights running," she said. "Clifford, you'll have me thinking you are courting me."
"I thought you wanted to go to this party," he said woodenly.
"I do, my dear. And I appreciate your taking me. Half a minute, while I gown." She got up and slipped out of the room with a slow-seeming, easy glide. Larsen Hazel had been a popular dancing star in her day, both record and beamcast. She had wisely decided to retire rather than fight it out with younger women. She was now just thirty, two years younger than her spouse.
"All ready," she announced after an interval hardly longer than her promise mentioned.
He should have commented on her costume; it deserved comment. Not only did it do things with respect to her laudable figure, but its color, a live Mermaid green, harmonized with her hair and with her sandals, her hair ornaments, and her costume clips. They all were of the same dull gold as the skin-tight metallic habit he had chosen.