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Volume 44, Issue 1
Displaying 1-7 of 7 articles from this issue
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CH. M. TAHIR, K. TSUNEWAKI1969 Volume 44 Issue 1 Pages 1-9
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSChromosomal location of genes for fertility-restoration, awnlessness, spelta-type ear and red coleoptile color of Triticum spelta var. duhamelianum, an effective fertility- restorer for the timopheevi cytoplasm, was determined by monosomic analysis. The results can be summarized as follows:
T. spelta var. duhamelianum carries a dominant fertility-restoring gene Rf3 on its chromosome 1B. Chromosome 7D exerts a weak suppressing effect to this gene. Awnlessness is mainly due to an epistatic inhibitor B1 in chromosome 5A, while chromosome 6D has a promoting effect on awn development. As to the ear type, chromosome 5A carries a spelta gene q1, whereas chromosomes 2D and 3D possess some modifiers to this gene. Red coleoptile color is produced by genes in chromosomes 7A and 7D, while five other chromosomes, 2A, 2B, 2D, 3B and 6A, carry weak suppressors.View full abstractDownload PDF (767K) -
MOTOMICHI SASAKI, TSUTOMU KAMADA1969 Volume 44 Issue 1 Pages 11-14
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSAn anomalous sex-chromosome constitution was observed by chance in a case of phenotypically normal female golden hamster. Bone marrow metaphases of this animal showed 44 chromosomes with a karyotype which was indistinguishable in general appearance from that of the normal male. Two tentative interpretations were made for the sex-determining mechanism of the present specimen: one is the XY constitution in which the Y chromosome had lost its male factors due to the interchange of genetic materials between the X and the Y at the time of meiotic segregation, and the other deals with a partial short arm deletion in one of the two X chromosomes.View full abstractDownload PDF (542K) -
TAKAO K. WATANABE1969 Volume 44 Issue 1 Pages 15-22
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSA recessive visible mutant, rbl was found in Kofu-Katsunuma natural populations of Drosophila melanogaster. It was frequently extracted from the same natural population and its equilibrium frequency in the population was assumed to be 0.04. The locus of rbl was determined to be 82.3 on the right arm of second chromosome and the mutant gene linked often with an heterotic inversion, In(2L)B, on the left arm. The homozygous flies for rbl had lower viability, developmental rate, productivity and fecundity than normal heterozygous flies. However, rbl heterozygous flies showed remarkable heterosis in productivity and fecundity though they were neutral in viability and developmental rate. In such a relation we may see the mechanism of persistent of rbl gene in natural populations. The role of inversion, In(2L)B, was assumed to enchance the heterosis of rbl gene or its closely linked genes at least in the cis-phase.View full abstractDownload PDF (763K) -
KOZO NISHIKAWA, YOSHIHIKO FURUTA1969 Volume 44 Issue 1 Pages 23-29
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESS1. Comparisons were made of DNA content per nucleus in common wheat, artificially synthesized 6x wheat, its parental species and three analyzers.
2. DNA content per nucleus in the D genome analyzer was the lowest, B genome had a little lower DNA content than A genome, but the difference between the last two was not significant.
3. Ssp. strangulata had a significantly higher DNA value than var. typica of the same species, Ae. squarrosa.
4. Two strains of synthesized 6x wheat, ABD No. 1 and ABD No. 13, have nuclear DNA equal to the sum of the DNA contents of their respective parents. Nuclear DNA content of cultivated common wheat (Chinese Spring) is quite the same as that of synthesized 6x wheat, especially ABD No. 13.
5. In three subspecies of T. aestivum, vulgare, spelta and macha no significant difference was found in DNA content per nucleus.
6. Based on the above facts, the following conclusion may be reasonably drawn as far as wheat and its relatives are concerned:
a) Appreciable changes of DNA content might have resulted from chromosome aberrations accumulated in the course of genome differentiation of a common primitive genome at the diploid level.
b) The three different genomes, once established, have been appreciably stable and kept the amount of DNA constant either in diploid or polyploid condition.View full abstractDownload PDF (717K) -
HARUYO ADACHI, MANABU INUZUKA, MUNEMITSU TOMOEDA1969 Volume 44 Issue 1 Pages 31-40
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe in vitro effect of 4-nitropyridine 1-oxide (4NPO) and its reductive erivatives on the transforming DNA in Bacillus subtilis was investigated. Among six compounds used, only 4-hydroxylaminopyridine 1-oxide (4HAPO) was effective to inhibit the transforming activity of DNA. The inhibition took place only in the presence of air.
This led to a conclusion that 4HAPO itself is not the ultimate compound in the inhibition process of the transforming DNA but an oxidation product possibly of free radical character may be primarily responsible for this event.View full abstractDownload PDF (887K) -
RICHARD S. SAKAI, YUICHIRO HIRAIZUMI1969 Volume 44 Issue 1 Pages 41-45
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe segregation frequency of the stw3 second chromosome in the male, when made heterozygous with second chromosome of the cn bw stock, was found to be dependend upon the sex chromosome constitution. This finding argues for a critical re-examination of previous viability estimations which used D. melanogaster as the experimental organism.View full abstractDownload PDF (427K) -
MASAO TANAKA, KAZUO NAKATA1969 Volume 44 Issue 1 Pages 47-54
Published: 1969
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn connection with the experiment previously reported (Nakata and Tanaka 1968), chromosome numbers of 53 adult tobacco plants developed from 3 cultured anthers were studied. Of these 49 were haploid, 3 were diploid, but chromosome constitution of one deformed plant could not be determined. The former two groups were thought to have been derived from developing pollen grains, while the latter one from callus. The young plants grown from calli had deformed leaves and majority of them did not survive so long beyond the incubation period. The haploid tobacco plants were easily distinguished from diploids by their narrower leaves, smaller stomata, shorter stamens, more slender anthers and completely abortive pollen grains. The low frequency of chromosome pairing and other meiotic behaviors of chromosomes were quite similar to those reported by Takenaka and Tanaka (1956).
In a preliminary experiment to obtain homozygous lines of tobacco, 0.4% colchicine in lanoline was smeared on several upper leaf axils of 34 haploid plants immediately after topping. Formation of abundant filled pollen due to chromosome doubling was found for the most part in the anthers of restricted flowers of the axillary cyme, that is, in the terminal flower or in several neighboring flowers on the lateral shoot. Such an appearance might have been brought about by chromosome doubling in restricted cells at the apical part of the primordia. After repeated cutting-back of the shoots and colchicine treatment, diploid seeds were obtained from more than 2/3 of the treated plants. The seedlings grown from diploid seeds were quite uniform with regard to their appearance and growth.View full abstractDownload PDF (932K)
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