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ID 12358
Eprint ID
12358
FullText URL
Title Alternative
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
Author
Morisawa, Tetsuo
Abstract
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.
Abstract Alternative
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.
Keywords
full and half sib covariances
quadrivalent chromosomes
additive genetic variance
variance of a family
covariance of a population
Published Date
2008-02
Publication Title
岡山大学農学部学術報告
Publication Title Alternative
Scientific Reports of the Faculty of Agriculture Okayama University
Volume
volume97
Issue
issue1
Publisher
岡山大学農学部
Publisher Alternative
Faculty of Agriculture, Okayama University
Start Page
25
End Page
31
ISSN
0474-0254 
NCID
AN00033029
Content Type
Departmental Bulletin Paper
language
日本語
File Version
publisher
Refereed
False
Eprints Journal Name
srfa