ID 12358 Eprint ID 12358 フルテキストURL 97_025_031.pdf 204 KB タイトル（別表記） 異数体を含むレンゲ人為同質４倍体集団での全兄弟と半兄弟の共分散の計算 著者 森澤 徹男 高知県立安芸高等学校 加藤 鎌司 岡山大学 抄録 Full and half sib covariances were investigated in an artificial autotetraploid population with random mating in Astragalus sinicus L.. Since a set of homologous chromosomes is not necessarily involved in aneuploidy, the covariances must be averaged for two cases, that is, with and without involvement. To average the covariances, the probability that a set of homologous chromosomes was involved in aneuploidy was assumed as 3/8, where “8” and “3” represent the chromosome number of a genome and the mean number of quadrivalent chromosomes formed in a euploid, respectively. The covariances were calculated under the assumption that quadrivalent chromosomes were distributed to the poles by 2-2 and 1-3 with probabilities κ＝ 0.8 and λ ＝0.2 (κ＋λ＝1) respectively, and that trisomic and pentasomic chromosomes were distributed by 1-2 and 2-3 both with a probability of 1. It was also assumed that the inbreeding coefficient of the parents was F＝ 0, and that 2x and 2x＋ 1 pollens and all female gametes could fertilize equally. The covariance of a family was taken as an average of the covariance of each sib combination in a family. As a result, the covariance of a population could be obtained as an average of the covariance of each family in a population. The coefficients of variance components calculated under these assumptions were different from those calculated under the same condition except that 2x＋ 1 pollen could not fertilize. Differences in the coefficient of additive genetic variance components were about 3.3% and 7.2% for full and half sib covariances, respectively. Coefficients of the other variance components were also different between the two cases. However, 2x＋1 pollen could rarely fertilize, since their ability to fertilize in a practical population were lower than 2x pollen. Therefore, it would be valid to calculate full and half sib covariances in an artificial autotetraploid population of Astragalus sinicus L. under the condition thatonly 2x pollen could fertilize. 抄録（別表記） 任意交配するレンゲ人為同質４倍体集団における全兄弟と半兄弟の共分散を計算した．特定の相同染色体が必ずしも異数体に関わるとは限らないので，特定の相同染色体が関わる場合と関わらない場合について共分散を計算し，平均しなければならない．共分散を平均するため，特定の相同染色体が異数性に関わる確率を３/８とした“８”と“３”はゲノム染色体数と正４倍体で形成される４価染色体数の平均値である．４価染色体は MI で確率κ＝ 0.8とλ＝ 0.2（κ＋λ＝１）で２-２と１-３に分配され，Ⅲ価染色体とⅤ価染色体は確率１で１-２と２-３に分配されるとし，２xと２x＋１花粉と雌性配偶子は等しく受精するとして共分散を計算した．両親の近交系数はＦ＝０であると仮定した．次いで家族の共分散を家族内の兄弟間の共分散の平均として計算し，集団の共分散を家族の共分散の平均として計算した．仮定に基づき求めた共分散の分散成分の係数は２x花粉のみが受精するとして計算した値と違っていた．相加遺伝分散成分の係数は全兄弟と半兄弟でそれぞれ3.3％と7.2％ずつ違っていた．他の分散成分も同様であった．実際のレンゲ人為同質４倍体集団では２x＋１花粉は受精能力が２x花粉より低く稀にしか受精しないので，２x花粉のみが受精するとして全兄弟と半兄弟の共分散を計算しても問題はないであろう． キーワード full and half sib covariances quadrivalent chromosomes additive genetic variance variance of a family covariance of a population 発行日 2008-02 出版物タイトル 岡山大学農学部学術報告 出版物タイトル（別表記） Scientific Reports of the Faculty of Agriculture Okayama University 巻 97巻 号 1号 出版者 岡山大学農学部 出版者（別表記） Faculty of Agriculture, Okayama University 開始ページ 25 終了ページ 31 ISSN 0474-0254 NCID AN00033029 資料タイプ 紀要論文 言語 Japanese OAI-PMH Set 岡山大学 論文のバージョン publisher 査読 無し Sort Key 4 Eprints Journal Name srfa