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No.19 (1972/12) >

 
Title :日本ウズラにおける近親交配とアウトクロス(畜産学科)
Title alternative :Inbreeding and outcrossing in Japanese quail (Department of Animal Husbandry)
Authors :新城, 明久
Authors alternative :Shinjo, Akihisa
Issue Date :1-Dec-1972
Abstract :近交退化の原因を追究するため, 比較的近交退化が起こりにくい近交S系ウズラを用い, 11世代まで近親交配を行ない, 成ウズラの3-5週間に産した卵について受精率, ふ化率, 育成率などの適応度を指標に調査を行なった。1.全きようだい交配を連続して行なうと適応度が著しく退化し, 5世代以降全きようだい交配を行なうことはできなかった。しかし系統内ランダム交配のような弱度の近交を組合せることにより近交係数を68.3%まで上げることができ, 系統を維持することが可能であった。なお, この方法によっても適応度の近交退化現象を防ぐことはできなった。2.近交系の適応度の退化はインクロス, トップインクロス, ボトムクロスなどのアウトクロスを行なえば著しく回復し, 顕著な雑種強勢現象が認められた。3.近交退化の原因は有害遺伝子のホモ接合よりむしろ多くの遺伝子座にあるポリジーンのヘテロ性の低下であると考察した。
The study was carried out with Japanese quailinbred S lineto search inbreeding depression. Inbred S line of Japanese quail was relatively low inbreeding depression line and inbred successively till the 11th generation. Various characters such as fertility, hatchability and viability were examined on eggs layed on 3-5 weeks by adult quails. 1. Owing to severe inbreeding depression, successive full-sib matings were encountered with serious difficulty of reproduction by the 5th generation. Therefore, subsequent inbreeding generation were made by combination full-sib mating with mild inbreeding, random mating in inbred line, as a result of such procedure, the line could be maintained and also the inbreeding coefficient of the line was succeeded to increase to 68.3% at the 11th generation. However, the occurrence of inbreeding depression could not prevent completely by this procedure. 2. Inbreeding depression of the inbred S line could be restored by means of outcross such as incross, topincross and bottomcross. The fact indicates that, it is based upon striking heterosis. 3. It is suggested that inbreeding depression is caused by decrease of heterozygosity of polygenes on many loci rather than by increase of homozygosity of deleterious genes.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4477
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.19 p.473 -480
Appears in Collections:No.19 (1972/12)

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