Chapter 14 - Things That Are Not True

Even until the end of the nineteenth century mothers were wont to suspend around the neck of their offspring cloth bags of stinking asafetida in the mistaken belief that it was a preventive of infection. Indeed, the amulet may have been so malodorous as to keep at a safe distance persons who might otherwise have come into closer contact with its wearer and so may have served its prophylactic purpose. The vile substance in itself certainly had no efficacy in the protection of children from disease. Any other means of rendering the child offensive enough to keep him at sneeze-length from others would have served as well.

The theory was superstition, purely and simply, an old-wives' tale handed down from one generation of ignorant crones to another. There are thousands of such erroneous beliefs which range all the way from the concept that tomatoes are poisonous and that feather beds protect sleepers from lightning, to the idea that frequent bathing of the human body is harmfully enervating.

The breeding and keeping of dogs has been cluttered up with as much superstitious trash as has the breeding and rearing of the human animal. The care of dogs has been left largely to uninformed underlings who have wished much of their empiric nonsense upon their betters. Until a comparatively recent time, indeed, science itself has been at little pains to disprove the erroneous ideas which have persisted since the siege of Troy.

We are loath to surrender our pet superstitions. But the world does move.

It is only such superstitions as affect the breeding of dogs that we have here to do with. Even for those which pertain to the keeping and maintenance of dogs—such as that milk causes worms, that a meat diet makes a dog vicious, or that gunpowder is a remedy for distemper—we have here no room.

The breeder who is actuated in his practices by his superstitious beliefs is deterred by just so much from his observation of helpful truths. The breeder who discards an otherwise useful bitch because she previously has had a litter of puppies by a mongrel dog is permitting an outworn and discredited superstition to disrupt his breeding program.

This particular belief that the heredity of animals is, at least in part, derived from mates to which their dams have produced progeny at some earlier time is known technically as telegony. It is often called "the influence of the previous sire." It is entirely disproved, although it received some credence in biology until recent times.

Indeed, Sir John Millet wrote his Two Problems of Reproduction in part to prove the validity of telegony. In that work he sought to show that stripes on the colt of a certain horse mare by a horse stallion were due to her having produced an earlier colt by a quagga stallion. Not only was the experiment inadequately controlled but it has since been recognized that many true horse colts show vestigial stripes in their early life.

Implied in the theory of telegony would be a concept that a human child would partake in its heredity of the attributes of any man by whom the mother had previously borne a child, and that maternal half-brothers are more closely related than that relationship is recognized to be. It would also imply that a bitch which had ever been pregnant to a given dog might forever afterward, to whatever dog she may subsequently be bred, produce progeny which would bear a hereditary relationship to her earlier mate.

So-called common sense, it may be said, should have convinced us that such a phenomenon is not possible. But common sense is not to be trusted in the face of scientific credence. However, our present knowledge of the genes and chromosomes is adequate to controvert the theory of telegony. No geneticist of any claim to scientific attainments now harbors the belief that the heredity of an animal is influenced by any sire to whom its dam had been mated except the immediate one who contributed his haploid set of chromosomes to the zygote from which developed the animal under consideration.

Dog breeders would do well to ignore telegony. Long believed true, it is outmoded and discredited. There are, even now, thousands of practical breeders who yet are unconvinced of its falsity and who believe that they would mongrelize their strain by breeding from a bitch which had had an earlier litter by a dog not of her own variety. Many a good bitch is needlessly eliminated from breeding programs by such ill-founded beliefs, and breeding operations are so hampered.

The discredit of telegony does not imply that a bitch may not produce puppies in one litter some of which may be by one sire and some by another. That she may do so, however, it is necessary that she shall be mated with more than one dog at the single heat.

No individual dog has more than one sire. If a bitch should be mated to two or more dogs at a single heat and produce puppies by more than one of them, no single puppy has more than one sire, and that sire is the one whence came the spermatozoon which fertilized the ovum from which he derived. The other dog or dogs to which the dam was mated contributed no part of the heredity of that particular puppy.

A bitch may be mated to two dogs at a single heat and produce a litter of puppies in which some members are by one sire and some members by the other sire. No puppy is by both sires. If one of her mates should be a purebred member of her own variety and the other mate or mates should be mongrels or members of some other variety, such puppy or puppies as result from the mating to the purebred dog are just as purebred as if the other mating had never taken place.

In such a litter it is not always easy or even possible to determine which sire is responsible for which puppy or puppies. Especially is this true at an early age and it is sometimes wiser to destroy the entire litter than to rear any part of it if there is any doubt of the authenticity of the pedigree of the puppies.

There have been a few cases in which bitches have been mated to two dogs of their own variety at the same heat and have produced litters, the members of which it has been impossible to attribute definitely to either sire. In such a circumstance, one of the dogs may be responsible for the entire litter; or some of the puppies may be by one dog, some by the other. No single puppy, however, derives a part of his heredity from one sire and a part from the other. He has one single sire, although it may be impossible to determine which of his dam's mates that sire may be.

It is sometimes possible to obtain registration for dogs of uncertain paternity, provided that both of the possible alternate sires are purebred and that the dam is of such excellence that the perpetuation of her germ plasma is essential for the furtherance of her variety. Such registration of thoroughbred horses with so-called alternate sires is not unusual. It complicates the records, however, and is to be encouraged only in most exceptional circumstances.

Another of the widely credited but mistaken beliefs is the one about "prenatal impressions." By that term is meant that the heredity of the progeny is influenced by mental or emotional processes of the dam during her pregnancy.

The world is full of people who explain their birthmarks by the fancied resemblance in the shape of such birthmarks to something which is alleged to have caused an emotional trauma to the pregnant mother. She may have craved strawberries or have seen a mouse, hence the shape of the mark. If the mother had gone to the circus, might the child have been born with riding boots? It is useless to try to convince persons who harbor such beliefs that they are not true. But the breeder of animals should be made soundly aware that the belief in such "prenatal impressions" is rank superstition.

The belief is one of great antiquity and has persisted so long that it is difficult to eradicate. Indeed, it is of Old Testament origin. In Genesis is cited the instance of Jacob, who bargained with his uncle, Laban, to accept as wages for his services as a shepherd such parti-colored lambs as should appear in the flock. Thereupon, the wily Jacob is recorded to have set up striped sticks before the pregnant ewes to induce them to produce striped and spotted lambs. There is a greater likelihood that Jacob had a pied ram in the shed in the back yard which Laban knew nothing about.

The ancient Greeks are known to have set up beautiful statues upon which their pregnant women were to gaze for the purpose of bettering the appearance of the children they carried. The fact is that looking at such statues had no effect whatever upon the progeny. Any reader who had read the chapter on "The Chromosomes and Their Genes" in the earlier part of this book will know that this belief is mere superstition and will know why.

This is not to say that an emotional shock, such as a great fright, to the pregnant dam will not in any way affect the progeny. It is to say that it will not affect the heredity of the fetus . It may so interfere with the metabolism of the mother as to affect adversely the nutrition of the fetus temporarily. It may even produce abortion. But the heredity is locked up in the genes and chromosomes of the gametes which united to form the zygote, and it is inalterable.

This matter of "pre-natal impressions" is another of the in-cubi of superstition which science lifts from the breeder's shoulders. Let him peel wands or carve statues, as many as he will, his bitches will produce neither better nor worse puppies.

The time and effort which he may devote to the establishment of such "pre-natal impressions". is entirely wasted and were much better employed in the making of correct mating and in the providing of nutrition and comfort to his stock, or even in the mere twiddling of his thumbs.

Indeed, the belief in "pre-natal impressions" is of a piece with the exploded belief in the inheritance of acquired characteristics. This belief has died hard even in scientific circles and there are even yet a few biologists, a very few of the old fashioned American and new fashioned Soviet, who continue to maintain the possibility of acquired characteristics being transmitted in heredity. Even they do not assume that such transmission is a common occurrence or that it has any bearing upon the work of the practical breeder.

Lamarck, whose name the theory of such inheritance of acquired characteristics bears, died long before Mendel began his epoch-making experiments with garden peas. The influence of Lamarck was so potent that the theories, however erroneous, which he promulgated tend to survive. That environmental influences do or can affect the reproductive cells seems to modern biologists impossible. There is no reason to believe that they do. However, it is also impossible to prove absolutely that they do not.

The tails of sheep have been docked for hundreds of generations and there is yet no tendency toward the natural shortening of that appendage. There is no evidence that the persistent shaving of the human beard for however many generations it has been practiced has any tendency to produce a race of beardless men. For however many generations the ancestors of a child may have spoken a given language, there is no natural disposition on the part of the child to speak that language rather than some other. He learns and uses the tongue he hears rather than the one his progenitors heard and spoke.

No training or conditioning is believed to be heritable. The instinct to point game is derived by inheritance in Pointers and Setters, as the herding instinct is natural to the Collie.

These instincts have been developed through generations of selective breeding and are as much a part of the individual as the color of his hair or the shape of his skull. They can be and are transmitted from one generation to another. The training or conditioning which is superimposed upon the instinct, for the purpose of making useful the animal which possesses it, however, cannot be transmitted. A Pointer does not produce better hunting progeny after he has had his education than before. The trainability which made it possible to train him may be handed on to his progeny; the training which he receives, or any part of it, cannot be.

The fact that a dog is trained proves that he was trainable. And the fact that great field trial winners derive from great field trial ancestry is no earnest that the parents' training was transmitted to their progeny, but rather their trainability. Great working dogs are bred from because they work, which proves that they are workable. Such dogs would transmit to their progeny the same ability to work even if they had never been used for work; but only the actual work they do, proves their ability to work and enables breeders to know that they can work.

The same is true of disease. Immunity to or predisposition for certain diseases may be inherent in the animal and transmissible to his progeny. The fact that he has had a given disease proves that he was not immune to it. His progeny begotten before he had the disease will be just as prone to contract it as the progeny begotten after the parent has had the disease.

The evidence in behalf of the inheritance of acquired characteristics may not all be in, and science maintains an open door for any new findings which may be interpreted as confirmation of the largely discredited theory. Such as have been presented, however, do not stand up under critical scrutiny. We do know that, even if it should be demonstrated that such inheritance were possible, it is possible only in a manner and degree that has no bearing upon the practical breeding of livestock and is of but academic interest to the breeder.

It may be objected that alterations in heredity which result from X-radiation may be considered as an acquired characteristic. Such is not the case for the characteristics so transmitted are not first impressed upon the body, but rather the germ plasma is itself directly affected. The use of X-radiation to alter heredity will hardly be of practical use in the breeding of higher animals, although it may revolutionize the breeding of domestic plants and result in a vast boon to agriculture. Experimentation in such X-radiation of gametes is only in its swaddling clothes and since it does not promise to be useful in the production of better dogs, only brief mention is made of it in this work.

Nor do we intend to say that infectious diseases cannot be contracted by offspring from their dam, even before they are born, but only that such diseases are not heritable, although the predisposition to them may be.

Since it is so well established that acquired characteristics are not inherited, it is, therefore, safe to use for breeding otherwise suitable animals which may have been accidentally injured or maimed. The exhibition career of a dog may be ended by a broken leg which affects the animal's gait, or by the loss of an eye. Such animals, however excellent, are liable to be neglected by breeders. Many a fine dog has been needlessly rejected in the stud because some accident has rendered him unsound or unbeautiful. Inherited unsoundness are liable to transmission, as are inherited predispositions to the development of unsoundness; but no harm can come of utilizing an otherwise useful animal with an acquired unsoundness.

And since educability only, and not education itself, can be transmitted, the fact that a dog has not been trained for a given use need not deter the breeder from employing him to produce progeny for that use. While the proof of the ability to be trained is in the training, a dog will usually show an aptitude for a certain kind of activity before training is undertaken. That aptitude is transmissible in heredity and should, of course, be taken account of. There is no reason to wait for a dog to be trained before he is bred from.

The matter of the age of breeding stock is one about which there is gross misapprehension. That it is desirable to mate aging bitches to young dogs, or vice versa, is a firmly fixed belief, but without scientific foundation. That they be sexually mature and vigorous is the only consideration necessary to be given to the age of animals to be mated. If both are young or both old (short of senescence), the mating is equally as desirable as if one were young and the other old.

Animals reach sexual maturity somewhat younger than physical maturity. A young male dog physically immature should not be bred from often enough to deplete his stamina, however excellent he may be. Indeed, this is especially true if he is of great excellence. But neither should a mature dog be over-used. However, there is no reason to expect that the offspring from a sexually mature but physically immature male dog will be inferior to the offspring which the same dog may beget later in his life.

Nor, on the other hand, is there any good reason why an aging dog should be discarded from the breeding program so long as he is fertile.

Statistics have been gathered and tables made to show the ages of various great sires at the time of the conception of their various successful progeny. Interesting, such data may be, but they will not bear critical analysis unless they be accompanied with further data to show what opportunities these sires may have had (both as to the number and excellence of the mates bred to them) to produce excellent progeny at other ages.

To breed from a bitch at her first heat if she is physically immature is doubtful wisdom. While maternity may tend to develop her, the nourishing of the foeti and lactation may deplete her stamina. Each such case is to be considered separately and when doubt persists, it is wise to wait for the second heat before breeding. Some breeders, especially breeders of Bulldogs and Boston Terriers, consider that an early litter, before the pelvis skeleton is thoroughly calcified, conduces to easier whelping of the first and of subsequent litters. There is grave doubt that the theory is valid.

Very old bitches are certainly questionable breeding material. Metabolism slows up with advancing age; and, while an old bitch may contribute to her progeny a heredity similar to that she gave her earlier offspring, she may not be able so adequately to nourish the developing foeti nor to provide her young with milk of pristine quality or quantity.

There is also a prevalent theory that a bitch should not have two successive litters by the same dog, no matter how satisfactory the mating or how excellent the results from the first union. To believe this is to believe nonsense. It is true that if a bitch has produced a superlative offspring in one litter, the laws of probability are that she will not produce another so excellent in her subsequent litter. Great puppies are not frequent enough for that. But if the mate by whom she produced the superlative puppy is the best and most suitable mate for her at one time, there is no reason why the mating should be discontinued. That she has produced a satisfactory litter is proof that she is a sound brood bitch and is equal proof that her mate was well chosen. The comprehension of the behavior of the genes, and the realization that the gametes are separate and individual entities, is ample refutation for this erroneous concept that mates necessarily should be changed from litter to litter.

As untenable as these other fallacies is that an organism derives certain attributes unvariably from its sire and certain other attributes from its dam; as, for instance (and this is the most prevalent version of the idea), that the exterior portions come from the sire, the viscera and constitution from the dam. We know that everything heritable is the result of the pairing of genes, one of each pair deriving from each parent. The resemblance of any attribute of the organism may be to either parent, to some ancestor of a parent, or to both parents and their ancestors. This superstition is so patently untrue to anybody who will examine it in the light of the gene concept that further discussion than to declare that it is untrue is unnecessary.

Dogs are advertised at stud as the "sires of large litters" and are touted as the producers of preponderant numbers of male progeny. These circumstances, so far as the male is concerned, are purely fortuitous. We have seen in earlier chapters that the size of the litter is determined by the number of ova deposited by the bitch, and that the male dog produces exactly equal numbers of male producing and female producing sperm. The male deposits enough sperm to fertilize millions of ova and he deserves no credit for the number of puppies in a litter. Whether an ovum is fertilized by a sperm which carries the X-chromosome or by one which carries the Y-chromosome is as much a matter of chance as anything can be in this world.

Nor can the sex of puppies be influenced or determined by any method yet known. This is discussed at considerable length in Chapter VIII and is mentioned here only because the efforts of practical breeders to obtain a preponderance of puppies of one sex or the other are futile and wasted.

Many breeders consider equal the breeding value of two full brothers more closely related than are other full brothers, and genetic relationship of two brothers depends upon the number of like genes they have received from their parents. We have demonstrated elsewhere how it is theoretically possible that full brothers may be genetically unrelated one to the other. This is a remote possibility, indeed, but it tends to show how variable the breeding worth of full siblings may be. One dog may be a consistently excellent sire and his full brother as great a failure.

It is true that identical twins, both developed from a single ovum fertilized by a single sperm, are as genetically alike as they are likely to be physically alike and that their breeding worth is equal. Among dogs, identical twins are rare phenomena, however, and are seldom recognized to be identical. Unless one has positive knowledge that two dogs are identical twins, one cannot accept a dog as a substitute for his full brother just because of the pedigree relationship.

It is, of course, reasonable to expect that brothers who bear close resemblance to each other have received many of the same genes from their parents, and the progeny of one such brother may be expected to bear a closer resemblance to the progeny of the other than if the two sires were not closely related. But this resemblance is not so great that the breeder is justified in complacency of choice between the two brothers as a mate for any particular bitch.

The belief that breeding animals must be in the optimum of coat growth and condition at the time of mating to produce the best coats on their progeny is perhaps not so prevalent among breeders of dogs as among breeders of cats and rabbits. It is, however, widespread among breeders of many of the longer coated varieties of dogs, particularly of the Toy varieties. There is no reason to think that it deserves any credence.

Excellently coated dogs, especially if of excellently coated ancestry, tend to produce excellent coats upon their progeny; but mates, one or both of which are "out of coat," shedding or in old broken coat or clipped coat, are as likely to produce good coated progeny as are the same two mates at another time when their coats are in nicest bloom. It is not the condition of the coats at the time of mating that must be considered, but rather the ability to grow correct coats. The genes in the chromosomes of the parents determine the length, density, texture, and color of the coats of the progeny and these genes are not altered by the temporary condition of the coats of the parents.

"Like begets like" is an old adage, almost an axiom, of the breeder's art. All that is wrong with it as a guide is that it happens not to be true. That like tends to beget like, however, is true. But that tendency may be of greater or lesser degree. Do not count upon it that "like begets like." In many instances like begets similar, although it is not always true. What is begotten is tied up within the genes and chromosomes of the zygote. It may be like either parent or like neither. The old confidence that like can be depended upon to produce like is too simple a rule. The art of breeding animals is much more complicated than that.

Modern genetics sheds a bright light upon the "like begets like" fallacy. Indeed, it enables us to comprehend why all these "things that are not true" cannot be true. If it did no more than discredit these mistaken beliefs which have for so many years complicated breeding practices without adding one iota to the results, they would not have been promulgated in vain. The fact is that they have not only served to show why these untruths cannot be true but they have offered us positive truths to take the place of the superstitions that have actuated the breeders of plants and animals.

These superstitions are difficult to exorcise. To many old-fashioned, practical breeders the denial of their cherished ideas will be heresy. Progress in the development of domestic plants and animals has been made despite the lack of enlightenment of so many practitioners of the breeder's art. But that progress has not been made because of the adherence of breeders to faith in outworn, medieval ideas, but has been made despite such adherence.

To give heed to these principles which are discredited and untrue is to neglect the scientific truths which enable one to formulate a breeding program and to put it into effect with an assurance that it will lead steadily, intelligently, and certainly toward the realization of the ideals toward which the breeder strives.

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