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Volume 63 (1988)
- Issue 6 Pages 501-
- Issue 5 Pages 413-
- Issue 4 Pages 283-
- Issue 3 Pages 217-
- Issue 2 Pages 113-
- Issue 1 Pages 1-
Volume 63, Issue 5
Displaying 1-6 of 6 articles from this issue
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Masahiro HIZUME, Hiroto SHIRAISHI, Akio TANAKA1988 Volume 63 Issue 5 Pages 413-423
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSFemale and male plants of Podocarpus macrophyllus (Thunb.) Lamb. were cytologically investigated. The chromosome numbers were 2n=38 in the female plants, and 2n=37 in the male plants. The chromosome complement in female was composed of 38 telocentric chromosomes, and that in male was composed of one large submetacentric chromosome and 36 telocentric chromosomes. Bright chromomycin A3 bands appeared at the proximally interstitial region of two middle-sized telocentric chromosomes in both the female and male plants and coincided with secondary constriction in position. DAPI-bands appeared at proximal regions of about two-third the large telocentric chromosomes, but did not in the large submetacentric chromosome and the small telocentric chromosomes. Seventeen bivalents and one trivalent were constantly formed at meiotic metaphase I in the pollen mother cells (PMCs). The trivalent displayed a conspicuous shape with one free chromosomal end. These chromosomes were segregated into an anaphase I group of n=18 with a large submetacentric chromosome, and the other anaphase I group of n=19. These observations on mitotic and meiotic chromosomes strongly suggest that sex of P. macrophyllus could be determined by the XXY type of the sex chromosome system.View full abstractDownload PDF (966K) -
VI. Variation and differentiation in tetraploid wheatKozo NISHIKAWA, Yoshihiko FURUTA, Satoru KUDO1988 Volume 63 Issue 5 Pages 425-434
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSVariation of α-amylase isozymes in germinating seed of tetraploid wheat was investigated by disc-isoelectricfocusing. A total of 102 strains of Emmer group were classified into 13 types according to the zymogram pattern, while Timopheevi group was very meager in variation; only three zymogram types were detected in 55 strains. Genetic differentiation between Emmer and Timopheevi groups was discussed based on the percentage of polymorphic loci, gene diversity and genetic distance estimated from the data presented here and those of esterase isozymes previously reported by Nakai (1978).View full abstractDownload PDF (390K) -
Machiko HATSUMI, Yoichi MORISHIGE, Ken-Ichi WAKAHAMA1988 Volume 63 Issue 5 Pages 435-444
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSMetaphase chromosomes of four species of the Drosophila nasuta subgroup, D. nasuta, D. kepulauana, D. kohkoa, and D. neveifrons, were analysed by the C banding method to clarify the chromosomal differentiation during speciation. Four species were different in heterochromatic regions of their chromosomes, especially microchromosomes of the fourth chromosomes and the Y chromosomes. Intraspecific variations of heterochromatic regions were also found among isofemale lines from various localities of D. nasuta, D, kepulauana, and D. kohkoa. Intraspecific variations of heterochromatic regions were not different from interspecific variations morphologically. From these results, the evolutionary process of heterochromatic regions was discussed.View full abstractDownload PDF (927K) -
IX. Characterization of fle(3)100, a female-specific lethal mutationTaeko SATOU, Kugao OISHI1988 Volume 63 Issue 5 Pages 445-456
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSA female-specific late-lethal mutation, fle(3)100, of Drosophila melanogaster was examined on its effects in XX-XO mosaics, and its interaction with various alleles of sex-determination genes tra-2 and dsx. Mosaic flies homozygous for fle(3)100 appeared at a high frequency (more than 80%) compared to the control heterozygous flies. Mosaics, however, rarely appeared when they had relatively large XX tissues. A significant reduction of the frequency of XX genotype was observed in the second and third abdominal sternites, suggesting the presence of a focus or foci of primary gene action in the internal organ or tissue near these structures on the blastoderm fate map. Chromosomal females doubly homozygous for fle(3)100 and tra-2 or dsx were not rescued. Females homozygous for fle(3)100 as well as those doubly homozygous for fle(3)100 and tra-2 died as pharate adults. Unexpectedly, chromosomal males doubly homozygous for fle(3)100 and tra-2 showed variations in viability ranging from about 20% to 100% depending on the alleles of the tra-2 locus examined. These males also died as pharate adults.View full abstractDownload PDF (1263K) -
Shin-ichi SONTA, Zhei KONGI1988 Volume 63 Issue 5 Pages 457-463
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSUsing Chinese hamsters heterozygous for T(2;10)3Idr and T(1;3)8Idr reciprocal translocations, the authors studied mitomycin C(MMC)-induced crossing-over on the interstitial segments. Marker chromosomes with unequal-length chromatids resulting from crossing-over were clearly detectable, and the frequencies of such marker chromosomes were constant among individual males which were heterozygous for the same reciprocal translocation. The frequency of MMC-induced crossing-over on the interstitial segments increased roughly with increase in dose. These findings, therefore, indicated that marker chromosomes with unequal- length chromatids in translocation heterozygotes may be a useful indicator for detection of the cytogenetic effects of environmental mutagens on germ cells.View full abstractDownload PDF (321K) -
Toshi NAGATA, Masami NOZAKI, Takashi MORITA, Aizo MATSUSHIRO1988 Volume 63 Issue 5 Pages 465-469
Published: 1988
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSMouse MHC class I gene expression in 8-cell embryo was examined by cDNA cloning. We constructed a cDNA library from 8-cell embryos of ICR mice and isolated a class I cDNA from 3.0×105 phage clones of the library. Sequencing analysis of this clone revealed it to include the cDNA fragment extending from the exon 6 of the cytoplasmic portion to 3′ untranslated region 1 of H-2K gene. Qa, Tla or other embryonic class I cDNA have not been isolated in the library.View full abstractDownload PDF (250K)
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