All issues
Successor
Volume 48, Issue 1
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
-
SUSUMU TAKAYAMA1973 Volume 48 Issue 1 Pages 1-9
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSSubchromatid-like structures were observed in metaphase chromosomes from mouse cells of primary cultures, HeLa cells and FL cells. The chromosome slides prepared by the routine air drying technique were stained with Giemsa (in Sörensen buffer, pH 6.8) after a treatment with one of saline solutions (2×SSC, Sörensen buffer, or Michaelis buffer, pH 6.8) at 60°C or 69°C for appropriate times (1 to 180 minutes). The double strandedness was especially clear at the heavily stained regions in a chromatid which corresponded to bands.View full abstractDownload PDF (4352K) -
YUKIMASA SHIRAISHI, TOSIHIDE H. YOSIDA1973 Volume 48 Issue 1 Pages 11-17
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe present study was undertaken to compare the banding patterns of human chromosomes produced by trypsin and urea treatment techniques. Banding patterns produced by these two techniques appeared to be essentially the same and specific in each pair of homologues. These patterns also enabled the recognition of specific segments of all individual human chromosomes. From the banding pattern produced by the two techniques a diagram of the pattern was proposed by a slight modification from our previous presentation (Shiraishi and Yosida 1972).View full abstractDownload PDF (3380K) -
YOZO KUROKI, RYUSO TANAKA1973 Volume 48 Issue 1 Pages 19-26
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe durations of a mitotic cell cycle and its component phases were investigated in the root meristematic cells of male Rumex acetosa by means of pulse labelling with 3H-thymidine autoradiography. The average duration of the mitotic cell cycle was determined to be 15.5 hours, and that of its component phases to be 2.4 hours for G1, 7.8 hours for S, 3.5 hours for G2, 0.9 hours for prophase, 0.5 hours for metaphase and 0.4 hours for ana- and telophase, respectively.View full abstractDownload PDF (630K) -
HIDEJIRO TAKAHASHI1973 Volume 48 Issue 1 Pages 27-33
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe genes participating in true or pseudo-self-compatibility of Petunia hybrida were analyzed. It was found that pseudo-compatibility is probably caused by polygenic system rather than S alleles, and that true self-compatibility is due to the change in S gene to Sf. Furthermore, the time needed for pollen-tube growth from stigma to ovary was examined in the plants showing various grades of compatibility. The result was that the lower the grade of compatibility, the slower was the growth rate.
It is supposed that in the style of self-incompatible plant exists certain substance named as S substance which suppresses pollen-tube growth of own pollen grains. The specificity of this S substance depends on S allele and its activity is probably controlled by polygene. Pseudo-compatibility may be brought about by lowered activity of the S substance and by increased vitality of pollen.View full abstractDownload PDF (561K) -
SADAO ICHIKAWA1973 Volume 48 Issue 1 Pages 35-40
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSPotted plants of Tradescantia ohiensis KU 7 clone (heterozygous for flower color) were exposed to 60Co gamma rays and/or scattering radiation in the gamma field of the National Institute of Radiation Breeding. Somatic mutation rates were scored in the stamen hairs for 16 days, and the genetic effects of direct gamma rays and scattering radiation were compared. Scattering radiation was proved to be about 27 or 25% more efficient in inducing somatic mutations than the direct gamma rays from 60Co source.View full abstractDownload PDF (525K) -
SUMIO MINAMORI, KAZUKO ITO, AKIKO NAKAMURA, YASUHARU ANDO, HATSUMI SHI ...1973 Volume 48 Issue 1 Pages 41-51
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSAnnual surveys of a natural population of Drosophila melanogaster have been made by setting up a survey station in Hiroshima City from 1961 to 1971. The surveys made through the 11years disclosed an increasing trend in frequencies of lethal plus semilethal second chromosomes and a decreasing trend in the frequency of allelism between lethals. The lethal plus semilethal frequency increased almost three fold (from 13% to 37%), and the allelism frequency decreased from about 5% to 1%. For this directional change; 1) the infection with a killing agent did not appear to be associated, since the frequency of infected flies was negatively correlated with the lethal and semilethal frequency, 2) the same correlation was observed concerning the frequency of delta-associating second chromosomes; hence, delta may not be associated, and 3) the effects of weather factors were not evident. The increase in lethal and semilethal frequencies and the decrease in allelism frequencies were interpreted to be due to an increase in population size during this decade, and the environmental change produced by man which might affect the increase was discussed.View full abstractDownload PDF (1099K) -
TOKI-O YAMAMOTO1973 Volume 48 Issue 1 Pages 53-64
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSAlbinism appeared in the globe-eyed goldfish (demekin) is not a simple Mendelian character but is the double recessive of two independently assorting autosomal genes since non-albino and albino types appear in the 15:1 ratio in the F2 generation. When scored on advanced embryos and larvae, however, the dark (normal), the light and the albino types appear in the 12:3:1 ratio, related in action of dominant epistasis.
Symbol M is proposed for the epistatic dominant gene responsible for normal melanin deposition as well as normal melanophore development, S for the hypostatic dominant gene governing slower melanin formation and slower melanophore development. The effect of the S is masked in the combination M, S, because of epistasis of the M to the S (M>S). The dark type, thus, is represented by either M, S or M, s, the light one by m, S and the albino by m, s. The F2 ratio scored on embryos and larvae becomes 12 dark (M, S and M, s): 3 light (m, S):1 albino (m, s).
In the light embryos and larvae, eyes darken slowly and melanophores are smaller in size and fewer in number, i.e., in earlier developmental stage. The degree of phenotypic divergence between the dark and the light types is gradually obliterated as development proceeds. Final melanin deposition as well as final state of melanophores become eventually the same since the two genes differ only in the time-relationships in the developmental process.
The M and the S act in the same sense like duplicate genes. Since, however, M>S in epistasis but not M=S, the mode of non-allelic gene interaction in this case may be termed as a dominant epistasis akin to duplicate genes.
The presence of the M and the S genes pertinent to melanin as well as melanophores in a number of the ordinary black-eyed varieties of the goldfish is pointed out.View full abstractDownload PDF (4194K) -
AKINORI UCHINO1973 Volume 48 Issue 1 Pages 65-67
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (1001K) -
KANJI ONO1973 Volume 48 Issue 1 Pages 69-70
Published: 1973
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (512K)
- |<
- <
- 1
- >
- >|