by Lloyd C. Bracket
First, it must be recognized that all faults, excellencies, capabilities and diseases of all living matter can be divided into two categories, depending entirely on whether they are (1) inborn, or (2) acquired.
To obtain a proper understanding of these two terms, it is necessary to study briefly another point. All life has its origin in what is known as the living "cell," the lowest form of animal life consisting entirely of one single cell. As the animal forms rise to a level above this simplest type of life, more cells are added and the creature becomes an organism of multicellular life.
The cells of which an animal is composed are of two kinds: the pro-creative germ, or birth cells, and the body cells. The first of these, the germ cells, are the most important in planned breeding and are the result of the fertilization of one cell, the ovum of the female, by another germ cell, the sperm of the male. Because these cells are the true bearers of the heredity of the individual, and their chromatin material passes on from generation to generation, they are the ones with which we are concerned in this study.
The second group of cells -- the body cells -- are essentially covering or protective cells. In higher animals they are always associated with the idea of protection and use and are of various kinds: such as, muscle cells, bone cells, skin cells, etc.
Because we are here mainly concerned with the matter of hereditable characteristics, rather than acquired, little need be said about the latter. it might be well, however, with the object of clarification in mind, to consider briefly some differentiation between the two groups of cells -- this particularly because, I have found, there is confusion in the minds of some beginner dog breeders as to what constitutes inherited characteristics in contract to those which are acquired.
So very many ask, when some fault of their dog is pointed out to them, "Can I do anything to correct it?" or "Will exercise improve the condition?" They thus indicate their confusion over the two types of cells. It seems to me that unless an understanding is had on this matter, there would be little help given to novices in the breeding art by the further consideration of a breeding program.
As is well known, there is never any growth without the stimulus of nourishment of some kind. Thus the GERM cells develop under the stimulus of nourishment, while the growth of BODY cells comes through the stimulus not only of nourishment, but also of use or injury. As examples, muscle is developed by use while the bad effects sometimes eventuating from distemper are caused by injury.
These points are important for an understanding of the subjects of particular interest to dog breeders, namely the inborn and acquired faults, virtues, or diseases of their stock.
INBORN TRAITS HEREDITABLE -- ACQUIRED ARE NOT!
It can thus be seen that the inborn and the acquired characteristics are in two separate classes.
The inborn is the result of the germ cells and is hereditable, which the acquired affects the body cells, is not continuous in its life, and so cannot be transmitted.
Take as an example rickets, which is a disease of the bones (the body cells) due to a lack of vitamin D, calcium and phosphorus. it is, therefore, an acquired disease and is not transmitted, although, through faulty metabolism, the ability to assimilate the above mentioned essentials of proper nutrition might be.
On the other hand, the short tails which often appeared in the descendants of Nores v.d. Kriminalpolizci back in the nineteen-twenties' German Shepherd Dogs were the result of an inherited trait due to genetic influence.
Contrasted to this, we find that the tails of several breeds of dogs, such a Fox Terriers and Dobermans, can be docked for generation after generation and, as this is a body cell injury and not inheritable, no change is made in the germ cells and succeeding generations of these dogs continue to come with long tails.
If the above principles are understood and applied to dog breeding, it will at once be seen that the main estimate of a good specimen are all dependent upon inborn characteristics and are therefore inherited.
By training, feeding, and other good care, they can be improved up to a certain PREDESTINED point, but beyond that it is impossible for them to be changed or improved.
This explains the characteristics which are hereditary and thus transmissible, but when we come to the manner in which they are transmitted, in what degree they re- transmitted, and how we can increase or eliminate them,the questions become much more difficult to answer.
Numerous scientists in the field of genetics have propounded various theories of animal breeding. As is well known, Mendel based his experiments on sweet peas, with which he explained the transference of characteristics from parent stock to succeeding generations. The characteristics of sweet peas are limited, but in dogs there are almost unlimited inherited factors and combinations of factors.
Gait for example, depends not only upon the conformation of the dog as regards his skeletal structure, but also upon the muscles working over it and the motor-nerve force stimulating them to action. The complexity of all these influencing factors is such that any attempt to use the Mendelian theory in the breeding of dog is, for all practical purposes, out of the question.
This law, now generally accepted by all authorities on animal breeding, presupposes that the two parents contribute, between them, half of the inherited traits, each of them, contributing one-quarter. The four grandparents contribute among them one-fourth of the inherited traits, or each of them one-sixteenth. The eight great-grandparents contributed amongst them one-eight, or each of them one-sixty-fourth, and so on, the whole inheritance equaling the sum of the series.
it might be well to interject here a mention of how little influence any grandparent or great-grandparent ha, when it appears no more than once in a pedigree, and also to indicate, to the proponents of continual out crossings, how they are misleading both themselves and those who listen to them when they point to some notable dog in the third or fourth generation of their dog's pedigree as being of particular value.
In order to apply Galton's law with any degree of success, an animal breeder should be in possession of very accurate data as to the characteristics of the ancestors of the mating pair, and this is often difficult to obtain. Furthermore, too few dog breeders are sufficiently interested in their breed's improvement to take the trouble to look for such data before making their matings.
A further hindrance to the obtaining of accurate information is that our conception of beauty and perfection is so changeable. Ideas regarding these attributes are comparative and subject to change continually, while perhaps not in the exact wording, at least in interpretation by the judges.
These differences of opinion and selections by judges, some qualified and perhaps more who are not, lead to confusion. they make all but impossible any definite standard of beauty or utility.
While, scientifically speaking, neither Mendel's nor Galton's laws can be applied, practically speaking there are known results which work out very much in accordance with them.
PRODUCING AND BREEDING HYBRIDS
For example, Mendel, in his experiments with sweet peas, bred together a tall and a short variety and got a hybrid generation. He bred thee hybrid together and found he obtained 75 per cent tall plants and 25 per cent dwarf plants. The small plants were then bred together and produced nothing but small plants, but the 75 per cent of tall plants, when bred together, produced two kinds: (1) a mixed collection of talls and dwarfs, and (2) nothing but talls, the ratio of talls to dwarfs being as 2 to 1.
In this way he learned that by breeding two hybrids (or intermediates) the result was 25 per cent tall, 50 per cent mixed, and 25 per cent dwarfs.
In all breeding it must be remembered that there are two types of characters, or factors, DOMINANT and RECESSIVE. In sweet peas, the talls were proven to be dominant and the dwarfs recessive, and each, when bred to its own kind, bred true; whereas the mixed when interbred produced the same formula of 25 percent tall or pure dominants, 50 per cent mixed, or impure dominants, and 25 per cent dwarfs, or pure recessives.
To set up the formula a simply as possible, we will take the letters PD to represent pure dominants (talls), PR to represent pure recessives (dwarfs), and ID to represent impure dominants (intermediates). The result of a union of two ID would work out as follows:
ID plus ID = 1PD, 2ID, 1PR
That is, there would be one pure dominant to three others.
THE FORMULA IN PRACTICE
If we consider some of our most prominent sires of the past whose records are available to us, as well as a few of the present dogs, we will find that occasionally there comes along a stud who seemingly sires outstanding specimens, as judged by their show wins. This is also true of bitches, as evidence by Ch. Nyx of Long-Worth, for example.
I am mentioning the elate Ch. Nyx here both because she is well-known to every Shepherd breeder, and because she has undeniably had a great influence for good on the breed than any other bitch, at least in comparatively modern times. Something of her record was given in an earlier installment and, while much more could be supplied, it would not serve my purpose here.
By the same token, I could use her grandson Ch. Vol of Long-Worth, were I to choose a male for the purpose.
Let us suppose that the parents of Nyx were both impure dominants and, for use in as simple a manner as possible, that the average litter is four in number. Then it is possible, even if not proven scientifically, that Nyx was the pure dominant, in various characteristics, in her litter.
While I found in actual breeding use that she was dominant in quite a number of characteristics, suppose we select one, rear angulation, to use here. (Although I am cognizant of the fact that rear angulation is not a simple genetic factor, but rather a combination of factors, it will nevertheless serve to well illustrate my point.)
Now let us set up some possible matings and their results. Taking the average litter as four, and figuring on three litters, there would be twelve puppies.
Nyx`, with dominant good rear angulation, if mated to a male with dominant good rear angulation, would produce all pure dominants. Mated to a sire with impure dominant rear angulation she would produce one-half pure dominants and one-half impure dominants. If mated to a pure recessive -- a male with straight angulation in the rear as a pure recessive characteristic -- she would produce all impure dominants.
These results may be tabulated as follows:
PD plus PD = all PD
PD plus ID - one-half PD, one-half ID
PD plus PR = all ID
Of the twelve puppies from the three sires, NYX would produce six pure dominants and six impure dominants, but no pure recessives, as shown above.
Now take a bitch who is an impure dominant in this factor of rear angulation, which for demonstration purposes we have selected as the trait to use as an example, perhaps one of the above ID offspring.
The formula works out as follows:
ID plus PD = one-half impure dominants, one-half pure dominants.
ID plus ID = one-fourth pure dominants, one-half impure dominants, one-fourth pure recessives.
ID plus PR = one-half impure dominants, one-half pure recessives.
Again taking the average litter as four, there would be twelve pups out of this impure dominant bitch, sired by a pure dominant male, and impure dominant male, and a pure recessive male. There would be three pure dominants, six impure dominants, an three pure recessives in the offspring.
Thus, from a pure dominant female there would be twelve puppies twice the number of good ones, or pure dominants for sufficient rear angulation, and no really poor ones. Again, as stated above, I used the bitch NYX in these illustrations only because she is better known amongst the fancy than any other bitch of the breed, with a record of producing winners from every mating.
In the actual working out of these theories it is perhaps easier to use a sire. His ancestry is usually better known, and through being bred to many bitches his classification as to whether he is PD, ID, or PR in certain factors is more easily and quickly determined.
All of this seems more simple than it is often found to work out in actual practice but we all know that, in speaking of the prepotency of a sire or dam, we mean to what extent that animal is able to predominate in he blend resulting from matings with it. Its prepotency may vary and extend to any degree up to an entire inheritance.
Earlier in this article I mentioned Galton's law and stated his theory that each ancestor contributed a certain proportion of the sum total in the offspring.
We will now take up what is sometimes termed "piling up the blood" of certain ancestors, or inbreeding and linebreeding, the terms used when the name of some ancestor appears several times in the pedigree. The exact term varies according to how many times the name occurs and where it occurs in the pedigree.
It stands to reason that if an ancestor's name appears twice in a pedigree, especially if it is not far back in it, then his influence must be greatly increased; if three times, then it is of still greater value.
In matings where similar blood is united -- where the pedigrees of each of the mating pair contain the name of notable specimen of the breed -- we often get results which are so fortunate as to cause us to speak of that particular mating as a "nick mating."
Suppose, for example, that a bitch has the blood of many sires but three of which we will designate as A, B and C. If she is mated to s stud who also has blood of different sires, but amongst them he also has stud C as a close ancestor, we will say, then the resultant offspring will more likely inherit the characteristics of the C dog than of A or B, or any other dogs in the pedigree.
If these characteristics are desirable and what we are striving to breed into our dogs, then the mating can be called a "nick mating." The Nyx mating to Ch. Marlo was an example, for this "D" litter containing six Champions (all that was ever shown out of the eight) is represented in a large percentage of our modern type, and later-day, prepotent American bred German Shepherd Dogs.
In as simple a manner as possible, let us try to apply this breeding theory.
All animal breeding operations must of necessity start with the female and, as it is a truism that "No stable is better than its mares," so is no kennel any stronger than its bitches. Too much stress can not be placed upon the importance of the careful selection of a prospective matron or matrons, and an entire chapter could be devoted to this subject. It is highly important to ascertain that the brood bitch is as free as possible from inherited, or inborn, faults.
Perhaps the easiest fault for a beginner to recognize, as well as the most important in many breeds, is that of temperament (again not the result of a single genetic factor), so I shall use that as an example here.
The brood bitch, then, should be free of inherited shyness or savageness, one fault about as bad as the other, the latter often a result of the first, and both probably as difficult to eradicate as any other fault in some breeds.
Careful selection of mates who are pure dominants in the matter of proper temperaments through several generations, is the only way to eliminate this, as with any other fault. Close breeding to pure dominants on the other side of the pedigree from the one showing the fault is the best and surest way to get rid of it.
Again, given a bitch whose pedigree is "hit-or-miss," with no definite breeding plan indicated in the combining of the blood of her ancestry -- a bitch whose pedigree is so open that there is nothing to "catch old of" -- the best results from any standpoint should be obtained by mating her to an inbred or linebred stud who is a pure dominant in as many desired requisites as possible. His influence should, and usually will, predominate over the traits of an outcross and hit-or-miss bred bitch. In practically all breeds there is a big majority of such bitches, the result of generations of careless outcrossings.
We will next consider a mythical bitch and try to plan a mating for her, with the object in mind of improving the mean or average quality of the breed.