Variations of Drosophila in relation to its environment:VI. Variations induced in the Kozi medium when transferred from the Pearl's medium

概要

論文の詳細を見る
1. We reported (Mori and Yanagishima, 1957; Mori, 1957) that Drosophila melanogaster (Oregon strain), which had long been reared by the Kozi medium, produced more eggs and grew up faster when transferred to the Pearl's medium. We supposed that these changes were more or less hereditary, induced directly by the change of environment, not by the combination of random variations and selection. Against this supposition Dr. Hideo Kikkawa expressed his opinion, saying that the phenomena must had been evoked by selecting the strong individuals concerning with metabolisms, and in this case the Pearl's medium must have operated as a minimal medium, whereas the Kozi medium as a complete one.2. This work was attempted to give some light into this sort of doubt. The flies that had long been cultured (ca. 200 generations) in the Pearl's medium were transferred to the Kozi medium, and the changes in the ability of producing eggs or in the durations of larval and pupal stages were examined. The results obtained are as follows.a) When the larvae of the fly, which has long been cultured by the Pearl's medium, are reared by the Kozi medium, they can emerge as well as their parents did in the Pearl's medium. However, when they are cultured more than 2 generations successively in the Kozi medium, the mortality rises up gradually.b) Every individual deposits more eggs on the Kozi medium than on the Pearl's medium, irrespective of their histories. However, when the fly grows up in the Kozi medium, the potential of producing eggs drops down below the level of the mother. Thus the Kozi medium is effective inducer of oviposition, but it descends ovipositing ability of the fly when it grows up in this medium.c) When the fly, which has long been cultured by the Pearl's medium, is reared in the Kozi medium, the duration of larval development is shortened at the first generation, but it becomes considerably lengthened at the next generation.d) All these facts indicate that it is not a easy matter to decide whether the Pearl's medium is minimal or complete when compared with the Kozi medium. It seems to me that the formal application of the theory of origin of variations based on the combinations of random vaaiations and selections needs to be scrutinized more thoroughly than is generally accepted.
日本遺伝学会の論文

著者

森主一
京都大学理学部動物学教室

Variations of Drosophila in relation to its environment:VI. Variations induced in the Kozi medium when transferred from the Pearl's medium

スポンサーリンク

概要

著者

関連論文

スポンサーリンク