• A. G. Searle

      Articles written in Journal of Genetics

    • Gene frequencies in London's cats

      A. G. Searle

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      The results are given of a survey of inherited characters in 700 London cats.

      The hypothesis of random mating was tested by using the results for yellow and tortoiseshell, and was found satisfactory.

      Gene frequencies were estimated on this hypothesis, and are given in Table 3.

      There was a significant tendency for male castration to increase hair length.

    • Inherited macrocytic anaemias of the house mouse - IV. The alleviating effect of blood injections

      A. G. Searle

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      Experiments on the intraperitoneal injection of normal blood intoW/W lethal anaemics show that the red blood cells pass through the peritoneum into the general circulation.

      The blood has the effect of a transfusion, alleviating the severity of the anaemia by its direct action and thereby prolonging life.

    • Genetical studies on the skeleton on the mouse - IX. Causes of skeletal variation within pure lines

      A. G. Searle

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      An account is given of the causes of variation in twenty skeletal characters found in the pure lines A and C 57 BL, percentages of the total variance due to each causative factor being summarized in Tables 62 and 63.

      Genetic differences within a subline, possibly due to a dominant gene reducing the frequency of foramina transversaria imperfecta, were found only once.

      In C 57 BL there is about as much genetic differentiation between closely related sublines as between those separated by over forty generations.

      Residual intangible non-genetic factors, acting independently on individuals or sides, account for over 80% of the variance in three-quarters of the characters studied.

      In 60% of lateral variants, one side (usually the right) is significantly more frequently affected.

      Where maternal age and/or parity have significant effects, a tendency is invariably found for early litters from young mothers to have the highest percentage of abnormals.

      Anomalies involving structural shifts are generally susceptible to maternal age effects; otherwise, there is no marked tendency for similar variants to be influenced by the same tangible factors.

      In both strains there is a high correlation between pregnancy prolongation and the number of young being suckled.

      Nearly all the variants are visible in foetal cartilage preparations.

    • Genetical studies on the skeleton of the mouse - X. Rarer variants in the a and C57BL pure lines

      A. G. Searle

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      Data are given on eleven uncommon variants found in the A and C57BL strains of mice, frequencies being summarized in Table 3. Nine of these variants are peculiar to one strain. While the tendency of a strain to produce a given anomaly is presumably under some sort of genetic control, the manifestation of these rare variants is mainly due to non-genetic factors.

    • Genetical studies on the skeleton of the mouse - XI. the influence op diet on variation within pure lines

      A. G. Searle

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      Tie effects of changes in parental diet on skeletal variation in the offspring has been studied in mice of the inbred strains A and C 57 BL.

      All three changes (to thiouracil in the drinking water of C57 BL mice, from a good cube diet to oats in C57 BL mice, from a good to a poorer cube diet in A strain mice) reduced the mean size of lower third molars. Results of fostering experiments and other data suggest that this is partly due to post-natal factors connected with the mother’s milk, which may even influence the size of first molars.

      Bight out of eleven C57 BL skeletal anomalies were significantly affected by the clange to an oats diet, three becoming rarer and five more common, as shown in Table 6.

      The frequency of dyssymphysis of the second thoracic vertebra increased from nil to 16% on the oats diet. In quite a different 057 BL substrain this anomaly is common on a normal diet; the oats diet thus produces a type of phenocopy.

      057 BL mice on thiouracil were somewhat retarded, but the only clear-cut effect of this substance on skeletal variation was an increase in the proportion of well-developed spinous processes on the second thoracic vertebra.

      The relation of these results to previous work on maternal influences in pure lines and nutritional deficiency effects is discussed, also their bearing on taxonomic studies. I am glad of this opportunity to thank Dr H. Grüneberg for his continued interest in this work and for many helpful suggestions. This investigation was carried out during the tenure of an Agricultural Research Council grant, which is gratefully acknowledged.

    • The ‘rex’ type op goat in the domestic cat

      A. G. Searle A. C. Jude

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    • A study of variation in Singapore cats

      A. G. Searle

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