• M. S. Pease

      Articles written in Journal of Genetics

    • Genetic studies in poultry - IV. On the barred plumage of certain breeds

      R. C. Punnett M. S. Pease

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    • On the pattern of the Dutch rabbit

      R. C. Punnett M. S. Pease

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    • Genetic studies inBrassica oleracea

      M. S. Pease

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      There are two independent factors,N1 andN2, which are normally present in the Kale type ofB. oleracea; when both these factors are absent, the common Cabbage heart developes under normal cultural conditions. Intermediate degrees of “hearting” are produced by one or two “doses” ofN.

      The Heart character shows “linkage” with a number of other characters. Clearly it is of interest to determine, in each case, whether linkage is with the factorN1 or withN2.

      There is one linkage group comprising the factorsN1, P for petiolate leaves as against sessile,E for entire leaves as against lyrate, andW which determines broad as distinct from narrow leaves. There is some evidence that there is also in this group a factorK1, one of the multiple factors for the Curly foliage of Scotch Kale.

      There is a second linkage group containing the factorsN2,T for tall habit as against sessile habit, and probably the factor K2 of the curly series.

      There are two so far unattached factors, one of which,D, differentiates between the purple and green types ofoleracea; the other,A, determines the “Asparagodes” malformation of the foliage.

      Thus the ten factors so far considered account for four of the nine chromosomes ofB. oleracea.

    • Genetic studies inBrassica oleracea II. The Kohl Rabi

      M. S. Pease

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      The swollen stem (or so-called bulb) of the Kohl Rabi is determined by three multiple factors, of which two are major and the third is a minor or modifying factor. This conclusion is arrived at from a consideration of the distribution of types inF2,F3, and the Back crosses.

      Intermediate, or Semi-bulb, types have been selected and shown to breed true

      The purple colour in the “blue” Kohl Rabi is due to two complementary factorsD and A.

      One of the major factors which controls the bulb in the Kohl Rabi is linked to the factorD, the crossover value being 30 per cent.

    • Genetic studies in poultry. V. On a case of pied plumage

      R. C. Punnett M. S. Pease

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      The “pied” character, a mixture of coloured, particoloured and pure white feathers (such as occurs in the Exchequer Leghorn), behaves as a simple recessive to self-coloured plumage. Pied chicks show a great deal more white in the down than normal blacks.

      An excess of white in the down may however be quite independent of the pied character, occurring in chicks which develop into normal blacks. Such “white” downs are recessive to normal black downs though the grade of pigmentation is probably complicated by a modifying factor, or factors.

      The bearing of these facts is discussed in connection with certain difficulties sometimes met with in making use of the sex-linked cross barred ♀ × black ♂.

      The experiments recorded in this paper have been carried out by means of the funds provided by the Development Commissioners for breeding research work with small animals.

    • Genetic studies in poultry. VI. The Gold Barred Rock

      R. C. Punnett M. S. Pease

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      The barring of the Gold Barred Rock, unlike that of the Chamois Carnpine, is due to a sex-linked barring factor. The Gold Barred Rock is essentially a buff with the addition of the barring factor. Evidence is adduced from a study of downs that the sex-linked barring factor probably exists in at least two allelomorphic states, differing in the intensity of their inhibitory action on the formation of pigment both in the down and in the adult plumage.

    • Experiments on the inheritance of weight in rabbits

      M. S. Pease

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    • Genetic studies in poultry. VII. Notes on polydactyly

      R. C. Punnett M. S. Pease

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      In conclusion we may add a few words on the impression which we have gathered from the available evidence as to the genetical nature of polydactyly in. the fowl. In the first place we feel little doubt that there is a definite factor for polydactyly. It is evident also that this factor can be carried by an apparently normal 4-toed bird. This is probably due to the existence of a factor (or possibly factors) inhibiting the action of the factor for polydactyly, and this factor (or factors) may be carried by normal recessive 4-toed birds. Further, since the evidence points to polydactylous birds being also capable of carrying the inhibitor, we must suppose that we are also concerned with some other factor, or factors, rendering possible the manifestation of the polydactylous effect in spite of the presence of the inhibitor. But although we have devised various schemes along these lines we have not found one which we consider satisfactory. Our failure, however, has been due more to lack of necessary data than to antagonistic facts. Where the gaps in the evidence are so large there are so many possible interpretations that we do not consider further efforts in this direction to be at present profitable. We agree with Dunn that “it is useless at present to frame more complex hypotheses since the data in a form wherewith to test them do not yet exist.” Yet through the tangle of facts we so often catch glimpses of apparent order that we feel confident that the solution, when it comes, will be found relatively simple.

    • Genetic studies in poultry - VIII. On a case of sex-linkage within a breed

      R. C. Punnett M. S. Pease

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