The Japanese Journal of Genetics
Online ISSN : 1880-5787
Print ISSN : 0021-504X
ISSN-L : 0021-504X
Volume 67, Issue 1
Displaying 1-4 of 4 articles from this issue
ARTICLES
  • Kozo NISHIKAWA, Yoshihiko FURUTA, Toshihiko YAMADA, Satoru KUDO
    1992 Volume 67 Issue 1 Pages 1-15
    Published: 1992
    Released on J-STAGE: January 19, 2005
    JOURNAL FREE ACCESS
    In order to investigate the phylogeny of polyploid wheat, the genetic variation of α-amylase isozymes in 127 strains of two diploid wheat species and five Aegilops species belonging to section Sitopsis was analyzed.
    Three types of zymogram were detected in 39 strains of Triticum monococcum and three other different types were detected in another diploid wheat, T. urartu. Two varieties of Ae. speltoides, var. ligustica and var. aucheri (subsection Truncata), were similar to each other and showed wide variation of zymograms. Sixteen strains of Ae. longissima and 13 strains of Ae. sharonensis were each grouped into four types. Ten strains of Ae. bicornis were grouped into three types, each including three or four strains. On the other hand, zymograms from five strains of Ae. searsii, which was formerly treated as a variety of Ae. longissima, were very different from those of Ae. longissima. In contrast to subsection Truncata, the zymogram types were rather simple and similar among species in subsection Emarginata (Ae. longissima, Ae. sharonensis, and Ae.bicornis) except for Ae. searsii. Finally, the phylogeny of tetraploid wheat was discussed on the basis of the results presented here along with those of the previous authors.
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  • Hiraku ITIKAWA, Yukiko MISHINA, Morimasa WADA, Hiroshi FUJITA
    1992 Volume 67 Issue 1 Pages 17-27
    Published: 1992
    Released on J-STAGE: January 19, 2005
    JOURNAL FREE ACCESS
    Temperature-resistant pseudorevertants were isolated from a dnaK7(Ts) mutant of Escherichia coli K-12. Two of these pseudorevertants were shown to carry suppressor mutations, sukA and sukB, respectively. Genetic mapping by conjugation and Pl-transduction revealed that these suppressor mutations were located at two distinct sites between 76 and 77 min close to the suhA and rpoH genes. Labeled cellular proteins were extracted from suppressor mutants grown at various temperatures and subjected to SDS-gel electrophoresis. Autoradiograms of the gels indicated that these suppressor mutations each resulted in increased synthesis of the heat shock protein Lon (an ATP-dependent protease, La) at both permissive and nonpermissive temperatures.
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  • Satomi YOSHIMURA, Atsushi YOSHIMURA, Akira SAITO, Naoki KISHIMOTO, Mak ...
    1992 Volume 67 Issue 1 Pages 29-37
    Published: 1992
    Released on J-STAGE: January 19, 2005
    JOURNAL FREE ACCESS
    Introgressed chromosome segments in three near-isogenic lines (NILs) of rice for bacterial blight resistance genes Xa-1, Xa-3 and Xa-4 with the genetic backgrounds of an IR24 variety were measured by using restriction fragment length polymorphic (RFLP) markers and linkage map. The size of the introgressed segment flanking Xa-1 of a NIL was estimated to be 3.3-11.7 cM of map units. Both NILs for Xa-3 and Xa-4 contained the donor segments at an identical end of linkage group corresponding to chromosome 11. We demonstrated in this study that these NILs were good materials to identify DNA markers tightly linked to these resistance genes and the RFLP markers tagging the resistance genes were useful in genetics and breeding on the disease resistance.
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  • Kishiko MARUYAMA, Hidenori TACHIDA
    1992 Volume 67 Issue 1 Pages 39-51
    Published: 1992
    Released on J-STAGE: January 19, 2005
    JOURNAL FREE ACCESS
    In order to clarify the effect of selfing on genetic variation in geographically structured populations, Wright's island model is generalized to include; the effects of extinction, mutation, selfing, and migration of pollen and seed. The equilibrium probabilities of identity by descent for two genes are obtained. It is found that selfing causes a decrease of the variation within colonies and an increase of the variation between colonies. Our model partly explains the "heterozygosity paradox" but other factors such as selection are necessary to fully account for the paradox.
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