巻号一覧
70 巻, 3 号
選択された号の論文の11件中1～11を表示しています
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ARTICLES
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Yuzuru OGUMA, Shuoyang WEN, Masatoshi TOMARU, Hiroshi MATSUBAYASHI, To ...1995 年 70 巻 3 号 p. 311-320
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーCourtship behavior and reproductive isolation between nine strains of Drosophila lini and its siblings from Taiwan (TWN), Dinghushan (DHS) and Nankunshan (NKS) in China, and Pyinoolwin (MMY) and Yangon (RGN)in Myanmar were investigated. No premating and postmating isolation between the Taiwan and mainland China strains were found. Crosses between mainland China (DHS and NKS) or the TWN strain and the MMY or RGN strain produced fertile F1 hybrid females and sterile F1 hybrid males. Crosses between MMY strains and RGN strains which showed strong premating isolation produced either no F1 hybrids, or fertile F1 hybrid females and sterile males in some cases. These results suggest the existence of at least three genetically distinct sibling species of D. lini.
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Takahiro YAMAGATA, Kyoko OHISHI, Muhammad O. FARUQUE, Joseph S. MASANG ...1995 年 70 巻 3 号 p. 321-337
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーThe musk shrew (Suncus murinus) is widely distributed throughout Asia and East Africa. The mitochondrial DNA (mtDNA) of this species was analyzed in individuals from 31 local populations in nine Asian countries and Mauritius, using 17 restriction endonucleases. Although fourteen and nine mtDNA haplotypes were detected from Bangladesh and Nepal, respectively, one to four haplotypes were found in each Southeast Asian country, and one common haplotype existed in Japan, Philippines, Vietnam, Thailand and Indonesia. Clustering analysis of mtDNA haplotypes classified shrew populations to three groups ñ continental group (Bangladesh and Nepal), islands' group (insular countries and Vietnam) and Malay group. The average nucleotide diversity among these three groups was calculated to be about 3.5%. These results indicate that the origin of feral populations in this species might be old and their population sizes are extremely large in the continent, and suggest a rapid spread of this animal throughout the islands. Although we have not shown yet an evidence of close relationships between islands' and continental mtDNA haplotypes, it is likely that the musk shrew had migrated from the continent in South Asia to the islands in Southeast Asia recently.
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Marie SANDA-KAMIGAWARA, Michio TOMIYAMA, Sadao ICHIKAWA1995 年 70 巻 3 号 p. 339-353
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーThe sectoring patterns of spontaneous and radiation- and EMS-induced somatic pink mutations were analyzed in the stamen hairs and petals of Tradescantia clones heterozygous for flower color (blue/pink). Spontaneous pink mutations were analyzed using clone KU 20 (a highly mutable clone especially at lower temperature) grown outdoors and clones KU 27 and BNL 02 (stable clones) grown under controlled environmental conditions, while induced pink mutations were analyzed using clones KU 27 and BNL 02 grown under the controlled environments. As for spontaneous mutations in the stamen hairs, the ratio of the number of single interstitial pink mutant events against that of single terminal pink mutant events was somewhat larger than 1 in all the three clones examined, indicating that somewhat more interstitial pink mutant events occur spontaneously than terminal pink mutant events. After treatments with X rays, gamma rays or EMS, however, the ratio increased to about 3 in the two clones examined, showing much more frequent inductions of interstitial pink mutant events than terminal pink mutant events by these mutagens. The daily changes of the sectoring patterns of radiation- and EMS-induced terminal pink mutant events in the stamen hairs showed a good accordance with the pattern of the stamen-hair development. Multiple pink mutant sectors in the same hairs were observed at much higher frequencies than expected from independent occurrences, especially in cases of spontaneous mutations in the mutable clone and of radiation-induced mutations in the two stable clones, suggesting the involvement of somatic recombinations. The sectoring patterns of radiation- and EMS-induced somatic pink mutations in the petals also showed daily changes which reflected the pattern of the flower-petal development.
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Shoji OHTA1995 年 70 巻 3 号 p. 355-364
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーTo elucidate the mechanism causing the intraspecific hybrid sterility in Aegilops caudata, chromosome pairing and segregation at meiosis and fertility were examined in sterile F1 hybrids, a tetraploid derivative induced from one of the sterile hybrids, and their parental lines. The F1 hybrids showed a normal configuration and frequency of chromosome pairing at MI but was completely sterile. At AI, chromosomes consisting of two sister chromatids different in length were observed. The induced tetraploid was shown to be an autotetraploid based on the configuration and frequency of chromosome pairing at MI, and it showed incomplete but obvious restoration of fertility. From the results, it was strongly suggested that the intraspecific hybrid sterility observed in this species is a chromosomal sterility caused by cryptic structural hybridity defined by Stebbins (1945, 1950). However, the differences in chromosomal structure between parental lines are presumably not great enough to cause preferential pairing in the induced tetraploid. Ae. caudata, thus, most probably is considered to be just on the way to speciation due to cryptic chromosomal rearrangements.
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Takahisa UENOYAMA, Yutaka INOUE1995 年 70 巻 3 号 p. 365-371
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーThe S2 line of Drosophila simulans, an isofemale line from a natural population at Mishima, Japan, was found to have high crossability with D. melanogaster. Over 80% of the S2 females mated with D. melanogaster males, while only 2.4-14.2% of control females from other D. simulans lines mated. The reciprocal mating (D. melanogaster females × S2 males) was in normal range (35-50%). The crossability of the F1 females between the S2 and other normal simulans lines was slightly higher than the control females. The high crossability is caused by at least two genes, one on the second and the other on the third chromosome which act additively.
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Yoshihumi KISAKIBARU, Hirotsugu MATSUDA1995 年 70 巻 3 号 p. 373-386
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーUsing DNA sequence data of 18 genes from 14 mammals, we analyzed how the average molecular evolution rate per year per site (Vy) depends on the generation time (g). (I) Assuming the relation Vy ∝g−α, the index of generation time effect, (α), was estimated to be about 0.14 for amino acid replacement substitutions (A), and about 0.32 for synonymous substitutions (S). (II) Assuming the relation Vy=Vmg g-1+Ve y, where Vmg and Ve y are constant independent of g, the fraction, re ≡Vey/Vy, of the mutation rate independent part (Vey) in the total evolution rate (Vy) was estimated under the assumptions of the star phylogeny and the constancy of the mutation rate per generation. re was smallest for mouse with the shortest generation time among our analyzed species, and it was estimated to be about 0.57 for A and 0.31 for S. Both results do not support the view that Vy is equal to the neutral mutation rate per site both for A and for S. They are in line with the thesis that, at least for A and probably even for S, the molecular evolution rate is influenced by some causes other than the mutation rate, such as changing environment.
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Myong Gi CHUNG, Soon Suk KANG1995 年 70 巻 3 号 p. 387-398
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーLevels of genetic diversity, population genetic structure, and gene flow in six Korean populations of Eurya emarginata were investigated based on allozyme variation using starch gel electrophoresis. Although most Korean populations are relatively small and isolated, with respect to their habitats, they maintain high levels of genetic variation. Fourteen of the 18 putative isozyme loci surveyed were polymorphic in at least one population. Overall, mean genetic diversity within populations (Hep = 0.296) was higher than those for most species with very similar life history traits. Analysis of fixation indices showed an overall slight deficiency of heterozygotes relative to Hardy-Weinberg expectations (54% were positive). Although significant differences in allele frequencies among populations were found for all 14 polymorphic loci (P < 0.05), about 92% of the total variation in the species is common to all populations (GST=0.079). Indirect estimates of the number of migrants per generation (Nm) (2.02, calculated from the mean GST; 1.10, calculated from the mean frequency of six private alleles) indicate that gene movement among populations of E. emarginata is comparable with those for plants with similar life history traits. It is likely that factors such as dioecy, high fecundity, long generation time, and occurrence in late-successional forests may contribute to maintain high levels of genetic diversity within populations and low levels of genetic divergence between adjacent populations of the species.
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Masayoshi SHIGYO, Yosuke TASHIRO, Shiro ISSHIKI, Sadami MIYAZAKI1995 年 70 巻 3 号 p. 399-407
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーThe chromosomal locations of isozyme gene loci encoding leucine aminopeptidase (LAP), glutamate-oxaloacetate transaminase (GOT), 6-phosphogluconate dehydrogenase (6-PGDH), alcohol dehydrogenase (ADH) and glutamate dehydrogenase (GDH) were investigated in shallot (Allium cepa L. Aggregatum group). The alien monosomic addition lines of A. fistulosum L. with the extra chromosomes (1A, 2A, 6A, 8A and other unidentified chromosomes) from A. cepa Aggregatum group were used for plant materials. The results revealed that the five gene loci, Lap-1, Got-1, 6-Pgdh-2, Adh-1 and Gdh-1, were located on the chromosomes 1A, 2A, 2A, 6A and 8A, respectively.
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Tetsuto KOBAYASHI, Shigeru HISAJIMA, Jens STOUGAARD, Hiroaki ICHIKAWA1995 年 70 巻 3 号 p. 409-422
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーThe enzyme activity for cytosine deaminase, which converts cytosine to uracil in bacteria, is usually undetected in higher plants and animals. The enzyme also catalyzes conversion of non-toxic 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU), a toxic compound for plant growth. The gene encoding cytosine deaminase (codA) from Escherichia coli was fused to cauliflower mosaic virus (CaMV) 35S promoter (P35S), and cloned into a binary vector pLABR101. The resulting plasmid pLABR102 contained two marker genes for plants: a positive marker gene, bialaphos resistance (bar) gene driven by the promoter from nopaline synthase gene (Pnos) and a negative one, P35S-codA. The binary vector pLABR102 was transformed into Arabidopsis thaliana via Agrobacterium-mediated transformation. In transgenic progenies (T3) of the second (T2) generation heterozygous for a single T-DNA insertion, a 3 : 1 segregation ratio was observed on both bialaphos (resistance to sensitive) and 5-FC (sensitive to unaffected). From T2 plants homozygous for the T-DNA insert, on the other hand, no segregation was detected: all the T3 seedlings were resistant to bialaphos and sensitive to 5-FC. PCR and Northern analyses showed that the 5-FC sensitivity in transgenic descendants was caused by the integration and expression of the chimeric codA gene in the Arabidopsis genome. The results indicated that cytosine deaminase from E. coli is functional and useful for negative selection in Arabidopsis, and that sensitivity to 5-FC as well as the positive bialaphos resistance are dominant traits in Arabidopsis.
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Ayami ARAI, Kiyoshi NARUSE, Hiroshi MITANI, Akihiro SHIMA1995 年 70 巻 3 号 p. 423-433
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーcDNA corresponding to two hsp70-related genes (OLHSC70 and CEHSC70) were isolated from two lines of cultured fish cells derived from the genus Oryzias. OLHSC70 was 2,261 bp in length and encoded a protein of 686 amino acids with a predicted molecular mass of 76,120 daltons. CEHSC70 was 2,114 bp in length and it lacked the 5' region found in OLHSC70. Two-dimensional electrophoresis revealed that Oryzias latipes has at least three heat-inducible proteins with molecular masses of about 70,000 daltons. One of these proteins (Hsp70.1) was barely expressed under normal conditions but its high-level expression was induced by hyperthermia. The other two proteins (Hsc70.1, and Hsc70.2) were constitutively expressed under normal conditions and only slightly enhanced levels were induced by hyperthermia. Transfection with the cloned sequence, RNA dot-blot analysis and the two-dimensional electrophoresis of proteins showed that OLHSC70 encoded Hsc70. 1.
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Naohiko KODO, Chiharu NAKAMURA, Hajime KATO, Takumi YOSHIAWA, Naoki MO ...1995 年 70 巻 3 号 p. 435-451
発行日: 1995年
公開日: 2004/06/24
ジャーナル フリーMitochondrial DNAs (mtDNAs) were purified by CsCl/bisbenzimide density-gradient ultracentrifugation from 21 strains of seven Fusarium species that cause fusarium head blight and mycotoxin contamination in wheat and other cereals. A partial PstI clone bank, from which one of twelve PstI fragments (14.7 kb) is missing, was constructed using mtDNA from strain KU-1615 of F. graminearum. Molecular sizes of mtDNAs of single representative strains from the seven species were determined after single-, double- and triple-digestion by four or five restriction enzymes (BamHI, MluI, PstI, PvuII and XhoI), while those of others were after single-digestion by BamHI and/or PstI. MtDNA size varied from the smallest 49 kb in one strain of F. avenaceum to the largest 116 kb in one strain of F. culmorum. Restriction fragment length polymorphism (RFLP) analysis revealed a large interspecific variation, thus all the species were identified by their restriction fragment patterns and assigned to individual clusters except for F. tricinctum in that a strain studied showed identical patterns to one of two strains of F. sporotrichioides. Considerable intraspecific variation including size variation was also detected. These results indicated a high incidence of insertions/deletions both between and within species. On the basis of results obtained by the cluster analysis, some aspects of taxonomy in these Fusarium species were discussed.
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