タイトル |
遺伝的多様性の維持を考慮したミヤコタナゴの水槽内での繁殖方法 |
担当機関 |
栃木県水産試験場 |
研究期間 |
2001~2005 |
研究担当者 |
久保田 仁志
|
発行年度 |
2005 |
要約 |
希少淡水魚ミヤコタナゴ飼育集団の遺伝的多様性の維持が可能な繁殖方法の検討を行った。親魚数および繁殖期間を数段階に設定して自然繁殖させ、得られた稚魚の遺伝的多様性を比較したところ、繁殖期間をより長く設定した区で遺伝的多様性は高く維持された。
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背景・ねらい |
ミヤコタナゴの保全のために生息域外での飼育繁殖による保全策の重要性が増している。しかし、水槽内での継代飼育では、遺伝的多様性の低下や遺伝子組成の変化などが起こる可能性が高いと指摘されており、遺伝的多様性の維持が可能な繁殖方法を確立することが課題となっている。そこで、繁殖に用いる親魚数および繁殖期間の違いが子世代の遺伝的多様性に与える影響について明らかにすることを目的に実験を行った。
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成果の内容・特徴 |
- 雌雄合計10、30、60個体(それぞれ雌雄同数)のミヤコタナゴ親魚を入れた150Lの繁殖水槽各6個で、3週間および9週間、二枚貝を用いて自然繁殖を行わせた。
- 繁殖によって得られた子世代の遺伝的多様性を、マイクロサテライトDNA(4遺伝子座)およびmtDNA調節領域の部分配列(500bp)をマーカーとして解析し、親魚母集団の遺伝的多様性と比較したところ、マイクロサテライトDNAにおける子世代の平均アリル数は親魚数が少ないほど低下していた(図1)。
- mtDNAのハプロタイプ多様度は、9週間繁殖させた実験区では親魚数によらず親魚母集団とほぼ同レベルの多様性を示したが、3週間繁殖させた実験区では親魚数が少なくなるほど遺伝的多様性が低下した(図2)。
- 親魚-子世代間の遺伝子頻度の変化量から求めた有効集団サイズNeは、同じ親魚数においては9週間繁殖させた方が高い値を示したが、Ne/N比はむしろ親魚数が少ないときの方が、より高い値を示した(図3)。
- 短い繁殖期間では、繁殖に係わる雌親魚の割合が低下することが明らかになり、それは産卵周期と関係していると考えられた。以上の結果から、限られた親魚数を用いて繁殖を行う場合は、できるだけ長い期間繁殖をさせることが、より多くの親魚の繁殖貢献を高めることに有効で、子世代の遺伝的多様性の維持に効果があると考えられた。
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成果の活用面・留意点 |
遺伝的多様性の維持が可能な希少魚類の飼育繁殖方法の確立により、生息域外保全、すなわち水産試験場や水族館などにおける希少魚の系統保存の有効な展開が期待される。
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図表1 |
![229774-1.gif](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-1.gif?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=d60791a3d04ed19e58d4f1c6261e43d131686a924de9aaebdca9d69a02ed3939) |
図表2 |
![229774-2.gif](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-2.gif?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=1a26275585e77e95cdddca90261db3632511ba5c0a3261c576c98a930ec5accc) |
図表3 |
![229774-3.gif](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-3.gif?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=7a38c7e6955b69e43390c59f5094e9a5e1db48a38d75607121efad55c3cc3d15) |
図表4 |
![229774-4.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-4.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=d0ef5b94e594fb9ba181a7aeedabb3c6f598e39dc012f8e002a2ee2480b20a0c) |
図表5 |
![229774-5.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-5.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=c15c919ec6d400307fd947a86798a273e29d7d388c2e7442c2bbdc6193ec773f) |
図表6 |
![229774-6.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229774-6.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEKv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDmFwLW5vcnRoZWFzdC0xIkgwRgIhAOIbDXW1k8Bid4JuNaxK4gg0ot%2FonZb7KzhXCEspOMTWAiEA9PUT1el6sAIHuNzqaBcKzuXm%2FJBf%2F5Sd0YgpYPZAONsqkAQIZBACGgw1MzIzMzEwNzIwNDEiDHTzboyNYlGxh4RplCrtA3timQqTKLh6z1bk2Uo15Y2iG6tdw5t07hghLgZUyJ0h8LSs5iFT9otzJ%2FvF3wugFfFRkOinL2AQpM4RR01%2BJzgUn4FNBt9QgAGvzYNGgjtaTcHiTfxZCD9Bd7MlINd5IKgWMG3JmkJ8CctBBxwISdxi9N%2BqgZri%2FJxpj32l%2Fo5b%2BSiTT2BZ670yoT19LvRTMFVGLCFkV%2Fi0VWFUvYhXlt4gfwRUZqyK0NCLbXcaw4T8fYx1SDwcRSEdXo0%2FTvvUexoYa5kR1ybl8xm9yqH%2B7etjYb0EnseW%2FDx1sBBJJJdL%2Fnht4ZQyJSF3AvqAnGQsOBvFwuMFtQtS1WtjwBjUiVk9xHFiWEZ%2Bj3X9oH9hGeNQ6KOCp3o9UOMl07kycH0o%2BX9D4YrTv3RPOFSNaqscxBsS%2FkY40JyyYArbUkedvIEU5iWYJsEEMaAoX0ZEEL2JXRal%2FG4rPLgTcva%2Bmdx7U1yKNU5svK%2FL5pp32gAK1cGaIyWSaHFFmU1Mk%2FVg%2Bods0EObGQgdNU2h5GDnlKNU9svMIvjMwUdVWVBItzhn7k0oAUmsJpvP6dZRC4MNiw0GO3R6GaH%2FdH7pALsHOBLkb0EGTZ9LYH3gvu2z8juevDTm6OeOYPqbcnYavqIT9QvhozmMNsXvHSllP3Q6wVAwvP%2BLtAY6pQENNNVHjID2KegYr7NGf7wxYA27VMDuWw0LsIEyVyC%2B9xdQdG7hkeCMtX0BBCyyCKMzNIhomeBdZZc1ruakHZhZw%2F451704Y8GjFmleOIlYA%2BeOqdZFKR0vlg1sfUPQ1f0pMg0ZHuh%2FiyBDMmBQuIzqJSRqeFGfg2XtsUjJ7LfTlZ33xtuzQvUdbQ740nt2xv5iqYu3H2Lw8xGDqWrJfamZibx0WPw%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU7DWSOENC%2F20240701%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240701T192230Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=837d023a9ef4a88bb4941c0c5ce3449fe463a8b80d40eb636de42860e48a9b9c) |
カテゴリ |
繁殖性改善
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