巻号一覧
64 巻, 4 号
選択された号の論文の5件中1～5を表示しています
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Masami HASEGAWA, Hirohisa KISHINO1989 年 64 巻 4 号 p. 243-258
発行日: 1989年
公開日: 2006/07/25
ジャーナル フリーA statistical analysis of complete DNA sequence data of mitochondrial genomes from human, bovine, and mouse (and partial sequence of rat) indicates that the transversion rate is lower in bovine than in human and murids, and that it is probably lower in human than in murids. However, it is unknown whether the transition rate is also lower in bovine. It is shown that the L-strand of human mitochondrial DNA has significantly higher C content and lower T and A contents than those of bivine and murids. This suggests that a directional mutation pressure which tends to change base composition has been operating in the human lineage.抄録全体を表示PDF形式でダウンロード (666K) -
Pascale BARBIER1989 年 64 巻 4 号 p. 259-271
発行日: 1989年
公開日: 2006/07/25
ジャーナル フリーTo examine the genetic differentiation between two ecotypes (annuals and perennials) in the wild rice species O. rufipogon, seeds and juveniles were collected from eight populations in Thailand, and compared regarding both life-history traits and enzyme loci. While no appreciable differentiation was found at the enzyme level, the two ecotypes showed a clear differentiation in life-history traits. This suggests either that gene flow occurs between the two ecotypes and ecotypic differentiation is maintained by selection, or that the annual-perennial differentiation is recent compared to the geographic differentiation between wild rice strains, and the evolution of life-history traits occurred rapidly.抄録全体を表示PDF形式でダウンロード (585K) -
II. Influence of the mating system and life-history traits on the genetic structure of populationsPascale BARBIER1989 年 64 巻 4 号 p. 273-285
発行日: 1989年
公開日: 2006/07/25
ジャーナル フリーIn order to examine the relationship between life-history traits and genetic variability, the variation at isozymic loci was investigated in annual and perennial ecotypes at two stages of the life-cycle. Outcrossing rates were also estimatedfrom maternal sibships collected from one annual and two perennial populations. Estimates of 0.04 in the annual, 0.50 and 0.56 in the perennials were obtained based on eight isozyme loci. It was found that: 1) the mating system influenced mainly the level of variation within population; 2) asexual populations and population with a mixed reproductive system differed mainly in their fine-scale intra-population structure; 3) the genetic structure of the annual ecotype depended more on extinction/recolonization events and on their fugitive habit.抄録全体を表示PDF形式でダウンロード (546K) -
Masahiro HIZUME, Teiji KONDO, Tomoko MIYAKE1989 年 64 巻 4 号 p. 287-294
発行日: 1989年
公開日: 2006/07/25
ジャーナル フリーMeioses in pollen mother cells (PMCs) were examined by the conventional staining and the CMA-staining methods in 15 clones of Cryptomeria japonica D. Don carrying three different karyotypes identified and classified by the characteristics of interstitial chromomycin A3 (CMA)-band or secondary constriction on the 6th chromosome pair. Before fixation of PMCs, a newly developed hypotonic treatment was applied for easy and constant preparation of well-spread meiotic chromosomes. At meiotic metaphase I 11 bivalents were observed, which possessed chiasmata at the interstitial region and/or the distal end. Although the CMA-bands were clearly observed on meiotic chromosomes, no chiasma was formed involving these bands. Most of the clones exhibited normal meiotic progression, but two clones (Syusou 5 and 11) showed some abnormal meioses. In Syusou 5 the heteromorphic 6th chromosome pair was involved in univalent formation more frequently than the other chromosome pairs. The normal meiosis in most clones with the heteromorphic 6th chromosome pair indicates that the heteromorphic chromosomes do not affect meiotic process.抄録全体を表示PDF形式でダウンロード (708K) -
Yoshiaki KITANI1989 年 64 巻 4 号 p. 295-313
発行日: 1989年
公開日: 2006/07/25
ジャーナル フリーIn Sordaria fimicola, the g-locus is composed of a single convertron and does not show intralocus reciprocal recombination. On the contrary, the i-locus is composed of multiple convertrons and shows genuine intralocus reciprocal recombination.抄録全体を表示PDF形式でダウンロード (966K)
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