Abstract
AN interesting series of articles on research in animal breeding appeared in the April-July issues of the Journal of the Ministry of Agriculture. In the first two papers the author, Prof. R. C. Punnett, traces the results of crossing red with black and polled with horned cattle, and in this way illustrates the Mendelian principles underlying all breeding methods. Mendelism not only enables the breeder to understand why red calves sometimes appear even in the most highly pedigreed Aberdeen, Angus, or Holstein cattle, but it also supplies the knowledge which can be used to prevent their ever appearing again. The factors with which breeders are concerned are rarely as simple as in the black-red case of cattle, where the possibilities form a simple alternative pair, and in both cases one of the characters is completely dominant to the other, black being dominant to red and polled to horned. A more complex example is given by crossing black polled with red horned cattle, which in the first generation yields all black polled animals, but in the second generation a very mixed progeny, arises. If the factors for the black-red and the polled-horned pairs are transmitted in the same manner, but independently of one another, then the second generation will consist of four classes: black-polled, black-horned, red-polled, and red-horned in the ratio of 9:3:3:1. This ratio has not been verified on a comprehensive scale for the cattle cross, but it has been worked out in all details in several cases for smaller animals. That horned-blacks and polled-reds appear in the second filial generation means that there has been a “break up” of the parental types, and the new classes arise through re-combination of the two pairs of factors in which the original parents differed.
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Problems of Animal Breeding. Nature 109, 57–58 (1922). https://doi.org/10.1038/109057a0
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DOI: https://doi.org/10.1038/109057a0