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Volume 46 (1971)
- Issue 6 Pages 371-
- Issue 5 Pages 295-
- Issue 4 Pages 223-
- Issue 3 Pages 141-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
Volume 46, Issue 3
Displaying 1-9 of 9 articles from this issue
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YUKIO KATO1971 Volume 46 Issue 3 Pages 141-146
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSMitotic abnormalities at anaphase and telophase were observed in the root meristem and also in the ovular tissue of young fruits of Clivia miniata Regel, grown in the greenhouse. From the data collected during a period from July 1965 to July 1968, the following conclusion is drawn: (1) There is a seasonal variation in their occurrence of aberrant cells. The chromosome stickiness becomes increasingly pronounced in correlation with high temperature. (2) The type of aberrations appears to vary according to different tissues.View full abstractDownload PDF (516K) -
TORU ENDO, B. B. SHAHI, CHIANG PAI1971 Volume 46 Issue 3 Pages 147-152
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn a number of rice cultivars, Oryza sativa, acid phosphatase zymograms were found to be of two kinds. Genetic experiments revealed that the isozymic difference between the two was due to alleles at Acp1 and Acp2 loci which are closely linked. Those two zymograms were detected in wild rice strains of O. perennis which is believed to be the wild progenitor of O. sativa. The genetic behavior of the isozymes was very similar to that of the isozymes of O. sativa. Although O. perennis showed many different acid phosphatase zymograms, semi-wild perennis-sativa strains were found like O. sativa to have the same two kinds. Probably, domestication, even in a primitive stage, may lead to genetic convergence for the genes specifying the acid phosphatase zymograms of rice.View full abstractDownload PDF (782K) -
TOSHIAKI KAMEYA, NORINDO TAKAHASHI1971 Volume 46 Issue 3 Pages 153-157
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDivision of chloroplasts was observed in artificial culture medium containing Ficoll and Dextran 40. Chloroplast number increased with time. But divided chloroplasts did not grow and division became irregular at 72 hours after isolation.View full abstractDownload PDF (406K) -
SHIGEMITSU TANO1971 Volume 46 Issue 3 Pages 159-167
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSFemale flies heterozygous for four kinds of recessive lethal genes on the second chromosome in homozygous genetic background showed high fecundity and the following results were ascertained by their persistence in the artificial populations.
1) Some lethals showed heterotic effect in homozygous genetic background.
2) Even these lethals which did not show high female fecundity in heterozygous background have been maintained at higher level than the theoretical one.
3) Decreasing patterns of each lethal heterozygote were similar in heterozygous and its irradiated genetic backgrounds.
4) The effect of irradiation gave rise to decrease the frequencies of lethal heterozygotes, but it was not clear in the case of heterozygous population.
However, the intimate relationship between female fecundity of lethal heterozygotes and equilibrium frequency of these lethal genes was presumed in the homozygous populations. So the fecundity was assumed to be an important factor in fitness and persisting mechanisms of lethals.View full abstractDownload PDF (727K) -
V. A VARIANT INHERITED BIPARENTALLY AT 25°CSUMIO MINAMORI1971 Volume 46 Issue 3 Pages 169-180
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESS1. A variant, denoted by delta r, of the extrachromosomal element delta (delta b) in Drosophila melanogaster was examined. The variant was carried by certain second chromosome lines, symbolized S-Cy, S-20, and SD-5 (Sandler, Hiraizumi and Sandler, 1959).
2. These three chromosomes were inviable when heterozygous for any of the other two in matings employing females of a line maintained at 25°C, or in matings employing daughters from males of these lines and females of an insensitive chromosome line (carrying no delta). Thus, delta r appeared to be transmitted biparentally at 25°C.
3. However, the heterozygous viabilities were normal when females of a line maintained at 18°C were used for matings. It is most likely that the multiplication of delta r may be delayed at 18°C.
4. Male and female heterozygotes for S-Cy and either S-20 or SD-5 produced only Curly phenotyped progeny in the presence of an appreciable amount of delta r.
5. A working hypothesis was presented that delta may be a copy of a chromosomal gene or genes, or of a certain agent which integrates inseparably into the chromosome of the fly.View full abstractDownload PDF (1230K) -
YOSHIHISA FUJIO1971 Volume 46 Issue 3 Pages 181-189
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSIn cross experiment, the deviation of genotypic class numbers from those expected was found in F2 and backcross segregation of only B blood group system, due to the fact that the number of heterozygous genotypes was larger than that expected.
The B blood group genotypes of zygotes associated themselves with marked differences in embryonic mortality over the whole incubation periods, especially at periods of 16-21 days of incubation.
The hatchability of each homozygote was lower than the mean hatchability in F2 and backcross. The maintenance of stable polymorphism could be explained by differences in mortality among genotypes.View full abstractDownload PDF (644K) -
KO KAWAGOE, MITSUHIKO KORESAWA, KOSO OHAMA, TETSUJI KADOTANI1971 Volume 46 Issue 3 Pages 191-194
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe degree of mixed leucocyte reaction from newborn-adult combination was significantly lower than that from the adult-adult combination. Although not statistically significant, the mixed leucocyte reaction from newborn-newborn combination was lower than that of adult-adlut combination, and nearly equal to that from newborn-adult combination.View full abstractDownload PDF (348K) -
TOMOKO OHTA1971 Volume 46 Issue 3 Pages 195-206
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSRandom frequency drift causes linkage disequilibrium and associative overdominance, and they have important bearing on the investigation of fitness values of marker alleles. Very often, experimental results merely reflect the effects of genetic background rather than the effect of the markers per se. Approximate magnitude of linkage disequilibrium and associative overdominance were estimated assuming various situations in natural populations. They mainly depend on Nec, the product of the effective population number and the recombination fraction. Also, the magnitude of associative overdominance was estimated assuming two models of experimental populations. In one model, a neutral marker gene is linked with a number of mildly deleterious mutants, and in the other it is linked with overdominant loci. Based on the results, the importance of associative overdominance in both experimental and natural populations was discussed.View full abstractDownload PDF (1115K) -
K. S. RAI1971 Volume 46 Issue 3 Pages 207-214
Published: 1971
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSDownload PDF (987K)
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