巻号一覧
33 巻, 1 号
選択された号の論文の3件中1～3を表示しています
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Meiotic Chromosome Aberrations induced by Absorbed Radioactive PhosphorusTEISAKU KOBAYASHI1958 年 33 巻 1 号 p. 1-12
発行日: 1958年
公開日: 2007/11/30
ジャーナル フリーFlower buds of sesame plant (Sesamum indicum L.) were internally subjected to β-rays from absorbed radiophosphorus (P32) by using three different methods, stem injection, radicle immersion and leaf immersion.
The applied radioactivity ranged from 0.005 to 1.5μc per ml. at the start of experiment.
The effects of β-rays emitted from P32 on living cells were measured by observations on the meiotic chromosome aberrations of the treated plants, and aberration frequency obtained proved to be proportional to dosage of β-rays.
Aberrations at MI, chromosome chains, rings and frying-pans were more frequently observed, and those at AI laggard chromosomes or acentric fragments were commonly seen throughout the treatment. Among β-ray effects were fragmentation, bridge, stickiness, formation of multipolar spindles and others.
Cells in tetrad stage, or pollen grains from treated plants exhibited many abnormalities in size, shape and number.抄録全体を表示PDF形式でダウンロード (1365K) -
Yukio YAMADA1958 年 33 巻 1 号 p. 13-22
発行日: 1958年
公開日: 2007/11/30
ジャーナル フリーHeritabilities and genetic correlations in some economically important characters were estimated and an attempt was made to construct an index which could be used under our farm conditions in Japan.
Heritabilities of rates of egg production were estimated to be 0.31, 0.17 and 0.15 for winter rate (P1), spring rate (P2) and total rate (P3) respectively, They were also estimated to be 0.48, 0.43, 0.46 and 0.49 for sexual maturity (S), body weight at sexual maturity (W1), body weight at approximately 300 days of age (W2) and egg weight at sexual maturity (EW), respectively.
Genetic correlations between P1 and P2, P1 and P3, and P2 and P3, were 0.187, 0.638 aed 0.701 respectively for production characters. They were estimated to be -0.210, 0.003 and 0.173 for SP1, SW2 and P1W2, respectively.
An index which could be applied under our farming conditions was proposed as follows:
I=1.40X2-X1+25.873X3
Where the subscripts 1 to 3 refer to sexual maturity, winter rate and body weight at 300 days. The economic weights assigned to the above three characters were -2, 5 and -1 respectively. The index is correlated 0.705 with the aggregate genotypic value of the birds.
Expected genetic changes in the means of the population selected on different criteria of selection were compared. It is evident that the efficiency of selection based on the index would be greater than selecting for any one of the characters involved in this study.抄録全体を表示PDF形式でダウンロード (610K) -
石原 隆昭, 吉田 俊秀1958 年 33 巻 1 号 p. 23-27
発行日: 1958年
公開日: 2007/11/30
ジャーナル フリー純系として確立していない So 系マウスに生じたMYマウス肉腫の移植に関与する遺伝的要因について調査した。F1 及び退交雑の移植実験からこの腫瘍の移植には, 2つの優性遺伝子 (H-遺伝子) が関与していることがわかった。このH-遺伝子はS及びD両系 (北大で純系繁殖された) に高頻度に存住しているが, アメリカから輸入した諸系統には存在していない。
移植が完全に成立した腫瘍を結紮除去した後, 同一腫瘍の再移植実験を行った, 腫瘍を結紮除去した場合のマウスには, 再移植の成立をさまたげる抗体の生産があった。この結果は近親交配系の腫瘍の場合と明らかに異っており, H-遺伝子の外に再移植をさまたげる遺伝的要因も関与しているのではないかと想像された。抄録全体を表示PDF形式でダウンロード (346K)
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