2018 Fiscal Year Final Research Report
Evolutionary ecology of asexual green alga Ulva prolifera including many heterozygous genotypes
Project/Area Number |
15K07194
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Biodiversity/Systematics
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Research Institution | Tokyo University of Marine Science and Technology (2018) Fukui Prefectural University (2015-2017) |
Principal Investigator |
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Project Period (FY) |
2015-04-01 – 2019-03-31
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Keywords | 種分化 / 生理的分化 / 走光性 / ヘテロ接合 / 無性生殖 |
Outline of Final Research Achievements |
Eight hsp90 genotypes of Ulva prolifera mainly detected from Mikata-goko and Minami River were distinguished into four ecotypes based on their distribution patterns: type I found throughout Mikata-goko, type II distributed in the downstream and entrance of Mikata-goko, type III observed in the downstream and entrance of Mikata-goko and Minami River, and type IV limited in Minami River. Tolerance against freshwater exposure and maturation rate in a low salinity medium were different among these ecotypes, suggesting their physiological differentiation. Furthermore, the examination of settled zoids in using hsp90 gene markers revealed that zoids of type I were detected from the entrance of Mikata-goko where thalli of type I had never been observed. Although zoids of various ecotypes were widely dispersed, the zoids of only ecotype(s) adapted to each environmental condition were survived under selection pressure, and this makes the distribution pattern of each ecotype different.
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Free Research Field |
藻類学
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Academic Significance and Societal Importance of the Research Achievements |
大型藻類の遺伝子解析が進み、様々な分類群で種内の遺伝的多型が検出されるとともに、遺伝子型(ハプロタイプ)の組成や頻度が地域によって異なることが明らかになってきた。しかしながら、その違いがどのような要因で生じ、維持されているのかほとんど分かっていない。本研究は、種内の遺伝的差異だけでなく、生理・生態的多型の存在を示すとともに、分布パターンの違いが維持される仕組みを明らかにした点で、意義深いものと考えられる。今後、同様な手法を用いて、様々な大型藻類について生理・生態的特性の解析や種分化プロセスの機構解明が進むことが期待される。
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