| Budget Amount *help |
¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2014: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2013: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2012: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Outline of Final Research Achievements |
The sex determining gene of medaka was identified as Dmy in 2002, but the molecular mechanism of the downstream of Dmy has not been clarified so far. In wild population of medaka, we can find 1% of XX-male or XY-female. By analysing the causal genes of these sex-reversals, we can expect to identify new genes related to the sex determination.
In the present study, we investigated three mutants, XY female from Shirone (Niigata Pref.), XY female from Sendai (Miyagi Pref.), and XX male from Hirado (Nagasaki Pref.). In the XY female from Shirone, some mutaitions on Dmy and a gene on chromosomes 4 were involved in the down regulation of Dmy expression. XY female from Sendai resulted from some mutation on the promoter region of the Dmy. XX male from Hirado had a mutated Gsdf, a downstream gene of Dmy, which can exhibit high expression without Dmy. These results ascertain that wild populations of medaka present us important key of the door to the sex determining cascade of this fish.
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