1999 Fiscal Year Final Research Report Summary
Inheritance of morphological and physiological characters in the inter-subspecific cross between Samia cynthia ricini and S. c. pryeri.
| Project/Area Number |
10660054
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
蚕糸・昆虫利用学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIMADA Toru The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (20202111)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Samia cynthia ricini / Samia cynthia pryeri / Diapause / Cold torelance / Sex determination / Trehalose / Supercooling point / Chromosome |
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| Research Abstract |
The F1 hybrids were obtained from a cross between Samia cynthia pryeri ♀× Samia cynthia ricini ♂. The F1 female pupae did not enter diapause, whereas most of the F1 male pupae enter diapause, suggesting that the pupal diapause nature is inherited in a sex linked manner. In the backcross progeny, the pupal diapause seemed to be sex linked. In F1 and B1 generations, the pupae did not show diapause under a long day photoperiod. The diapausing pupae of S. c. pryeri and the F2 hybrids were incubated at 4℃ vs. 25℃ for 100 days, and their trahalose content and supercooling point in the hemolymph were measured comparatively. In 25℃- and 4℃-incubated pupae of S. c. pryeri, the trehalose content was 15mg/ml and 34mg/ml, respectively. In 25℃- and 4℃-incubated pupae in the F2 generation, it was 14mg/ml and 18mg/ml (average), respectively. In 4℃-incubated pupae in the F2, trehalose content varied from 5 to 37 mg/ml among individuals. The supercooling point was -27℃ in the 25℃-incubated pupae and -21℃ at 4℃-incubated ones, in average. No correlation was observed between the supercooling point and trahalose content in F2 individuals.
Based on my observation of the backcross progenies, it was clarified that the green skin color in S. c. pryeri was controlled by a dominant gene on an autosome. The black spots on the skin of S. c. pryeri was also controlled by a dominant gene on another autosome. The cocoon of S. c, pryeri was brown. The cocoon color was segregated in the B1 generation, and various kind of colors were observed. Some genetical analyses led me to explain the cocoon color by a model ; A gene(s) and another gene(s) control a red pigment and a gray pigment, respectively.
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