人工單性發生で出來た白色のカエル
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概要
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Three albino frogs and one albino tadpole (died in 15 mm. length stage) from the same female frog, Rana nigromaculata, and one albino tadpole from another female frog of the same species were obtained by artificial parthenogenesis. The tadpoles showed slightly female differentiation, but had no hypophysis, although the thyroids were well developed. They showed albinism with contracted melanophores, and could not complete metamorphosis. The three albino frogs were females, and had a normal hypophysis, especially well-developed pars intermedia, and normally developed thyroid glands. Because of the presence of abnormal hypophysis and a normally functioning thyroid gland, these three albino frogs were able to complete metamorphosis. Obviously the albinism of these three frogs is caused by the decrease of the number of melanophores, the quantity of the melanin contained in them and also the enlargement of the xanthophores. Thus it differs from the so-called albinism of color changing animals in that it does not depend on the contraction of the melanophores. It is likely that this peculiarity is genetic. The mother of the three albino frogs may have had the albino gene in heterozygous condition, so half of her eggs had an albino gene. The artificial parthenogenesis induced the duplication of the chromosomes of some of these eggs, so that the albino gene became homozygous. The fact that, of six tadpoles developed from the same female by artificial parthenogenesis, four were albino and two were normal is another evidence bearing out the same conclusion.
- 社団法人日本動物学会の論文
- 1949-10-15