The choice of a mate.

  • Anthony Ludovici
Date:
[1935]
Catalogue details
    92/546 page 62
    from the two different shops first considered, which in the language of genetics are called “ heterozygous ” (i.e. having different hereditary equipment), and it is essential to remember that this unlikeness is above all noticeable in the absence of reces sive or any other kind of deleterious factors, which have all been mendelized out. As humans, they would therefore have become homozygous and stabilized, and we could begin to calculate with a considerable amount of certainty upon their offspring. 1 If then we continue to inbreed from them, we may do so quite safely, because the chances of morbid or lethal factors coming together in the offspring in any high percentage have now been removed. The stock is in fact pure and will breed true. 2 Beauty is likely to have increased, because, as we shall see presently, it is largely dependent on harmony ; health is likely to have increased, because, in addition to the elimination of morbidity-determining factors, dysfunction, as we shall also see, will have been avoided by an increased correlation between the parts of the body ; and appearance will become reliable as a measure of hereditary potentialities in germ-plasm, because the germ-plasm of the stock will have become stabilized. Thus, although in the early stages of close inbreeding from a stock hitherto random-bred, a great number of casualties are produced by concentrating the deleterious factors in the stock, it should not be forgotten that a parallel concentration of the finer qualities of the stock takes place in other individuals, and that when once the deleterious factors have been mendelized out, the stock is purified ; whereas in cross, or out-breeding, if a rapid production of casualties is avoided, it is only by covering up morbid factors and spreading them further afield. It is now established, in fact, that consanguinity in itself is not a bar to mating. 3 If inbreeding results in disappointment it is not the method of mating that has created the taints revealed. 3 Buchanan Smith (op. cit., p. 194). “ The primary effect of inbreeding is merely the creation of homozygosity . . . inbreeding per se is merely the stabilisation of the germ plasm.” 2 R.H., p. 157. “ Where no morbid variations exist, as in the case of old well- adapted families which for several generations have been clear of defect, con sanguineous marriages may be practised with no bad effect. Indeed they tend to accumulate homogeneous determiners in the germ-plasm, and so families which are thoroughly healthy in all their members may practise consanguinity with advantage since each new union will result in the accumulation of favourable combinations.” 2 H., p. 66.
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