The Japanese Journal of Genetics
Online ISSN : 1880-5787
Print ISSN : 0021-504X
ISSN-L : 0021-504X
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Volume 32, Issue 7
Displaying 1-6 of 6 articles from this issue
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  • Polyploidy Studies in the Brassiceae, IV
    Investigations on the Cytology and Fertility of Autotriploid Raphanus
    Ichizo NISHIYAMA
    1957 Volume 32 Issue 7 Pages 203-207
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.203
    JOURNAL FREE ACCESS
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    1. Almost all of small seeds set on the tetraplold radish in the free pollination of 2x- and x-pollen grains were found cytologically to be triploid hybrids.
    2. The triploid hybrid showed a variation of chromosome configuration at meiosis from 9III to 3III+6II+6I, with 6III+3II+3I as the mode. The frequency of appearance of univalents is 25.7% at metaphase I of PMC-s. About half of lagging univalents at anaphase I divided longitudinally and their halves went to opposite daughter nuclei. The elimination of univalents at telophase II was found to be about 15.4% of the theoretical total number of univalents.
    3. It is especially noted that triploid plants have unexpectedly high percentage of good pollen grains and of set seeds, that is 72.3% of normal pollen grains and 1.87 seeds per capsule as compared with 98.0% of normal pollen grains and 3.50 seeds per capsule in the diploid variety.
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  • 'Sex-Ratio-J' in Drosophila bifasciata
    I. A Preliminary Note
    Daigoro MORIWAKI, Osamu KITAGAWA
    1957 Volume 32 Issue 7 Pages 208-210
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.208
    JOURNAL FREE ACCESS
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  • Further studies on the chemical method to distinguish heterozygous individuals from homozygous ones in Drosophila
    A correction of the previous paper
    Hideo KIKKAWA
    1957 Volume 32 Issue 7 Pages 211-212
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.211
    JOURNAL FREE ACCESS
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  • An Unstable Strain of Ustilago maydis
    Tatsuo ISHIKAWA
    1957 Volume 32 Issue 7 Pages 213-222
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.213
    JOURNAL FREE ACCESS
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    The mutaion rate of the unstable strain T4001 of Ustilago maydis w as determined by three different methods. The rate was 1.4×10-3 per sporidium per generation. The mutants formed two groups differing in reversion rates and were all homocysteineless.
    The temperature coefficient (Q10) of the unstable strain was 1.3 and the activation energy for the mutation was 0.24ev. The ultraviolet dose-effect curve showed the peak and decline found in many other organisms.
    From these results, it is concluded that strain T4001 has an unstable state of the genic substance at the homocysteine locus.
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  • Studies on the host-range mutation in T2 bacteriophage
    II. Frequency distribution of the host-range mutants among individual bacteria
    Yoh TANAMI
    1957 Volume 32 Issue 7 Pages 223-228
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.223
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    Frequency distribution of the host-range mutant phages (phenotype hc) among individual bacteria infected with T2 phage was investigated for the purpose of analysing the mutation process as well as the mode of intracellular virus multiplication.
    The distribution of the hc-mutant clones with respect to their sizes was clearly an exponential type indicating that the replication of virus genes proceeds in sucu a way that replica themselves may serve as patterns for additional replications.
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  • Chromosomal polymorphism found in natural populations of Drosophila (a preliminary report)
    Yasuko TOYOFUKU
    1957 Volume 32 Issue 7 Pages 229-233
    Published: 1957
    Released on J-STAGE: May 21, 2007
    DOIhttps://doi.org/10.1266/jjg.32.229
    JOURNAL FREE ACCESS
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    This is a preliminary report on the polymorphism of the salivary gland chromosomes occuredng in the natural populations of Drosophila in Hokkaido. Twelve different kinds of chromosomal variations were observed in eight strains from the following five species: D. bifasciata, D. immigrans, D. melanogaster, D. nigromaculata and D. sordidula (Figs. 1-14). Among them, seven types were found to occur in D. immigrans collected in the University Botanical Garden, Sapporo.
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