All issues
Successor
Volume 56 (1981)
- Issue 6 Pages 565-
- Issue 5 Pages 447-
- Issue 4 Pages 349-
- Issue 3 Pages 241-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 56, Issue 3
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tosihide H. YOSIDA1981 Volume 56 Issue 3 Pages 241-248
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSKaryotype of the large naked-soled gerbil, Tatera indica, was investigated by conventional, G- and C-band stainings. This animal had 68 chromosomes, comprising 25 acrocentric and 8 biarmed autosome pairs, besides an X-Y pair. The X-chromosome was characterized by the largest metacentric, and the Y a small acrocentric. The smallest biarmed autosome pair (no. 33) was polymorphic by having three chromosome types (A, B and C). Based on the frequency of the polymorphic chromosomes, type-B (small submetacentric) was suggested to be an original form; type-A (large submetacentric) was derived from type B through tandem duplications of both arms, and type-C (small subtelocentric) was accounted for by inversion and deletion of the basic type.View full abstractDownload PDF (328K) -
Naoko KAWAMURA, Tohru NAKADA1981 Volume 56 Issue 3 Pages 249-256
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSDeposition of large-size eggs by tetraploid females of the silkworm has been reported by many investigators, while no detailed analyses have been carried out on the cause of the increase in egg size due to chromosome doubling. In this insect, a sex-linked gene called ‘Giant egg (Ge)’ is known, and the diploid females with Ge-gene lay remarkably large-size eggs.
In the present study, tetraploid females of F1 hybrids which do or do not carry Ge-gene were induced by applying a low-temperature treatment, and the effect of the chromosome doubling was compared to that of the doubling of Ge-gene on egg size. Eggs of the tetraploid females for both hybrids showed a remarkable increase in size, although the increment was relatively small in the females with the double Ge-gene dose. Furthermore, especially large eggs laid by some of Ge-progeny were all unfertilized. The results suggested the possibility of a limitation of egg size increase in the silkworm.View full abstractDownload PDF (607K) -
Samuel H. HORI, Soichi TANDA1981 Volume 56 Issue 3 Pages 257-277
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSConsiderable variations in activities of two X-linked enzymes, G6PD and 6PGD, have been observed within and between various strains of Drosophila melanogaster which were made homozygous for different X chromosomes sampled from natural populations. Although the loci coding for these two enzymes were both found to be segregating for two electrophoretically distinguishable alleles in the populations studied, the enzymes purified to homogeneity from the different genotypes were mutually indistinguishable with respect to several enzymological and immunological parameters. It seems therefore that the observed variations in enzyme activity would be attributable to variations in enzyme quantity, but not in enzyme quality. This was confirmed immunologically.
Five isogenic strains tested all responded immediately and rapidly to upward and downward selection for G6PD activity. This suggests the presence of a modifier gene system outside the X chromosome. Although the number of genes constituting the system is not known at present, it is likely that there may be a major gene segregating for at least two alleles, high- and low-activity, to which the observed variations in enzyme amount would be primarily ascribed. This autosomal modifier system is functioning throughout development, and has influence also on activities of 6PGD and HAD.View full abstractDownload PDF (1041K) -
Stephen F. NG, Kazuyuki MIKAMI1981 Volume 56 Issue 3 Pages 279-286
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThree cell lines initiated by transplantation of the micronucleus into amicronucleate recipient underwent abortive autogamy: the micronuclei disappeared in 95% of the autogamous cells and nonfunctional macronuclear anlagen were formed in a few; all postautogamous cells died except when regeneration of fragments of the prezygotic macronucleus occurred. The physical basis for the abnormality was investigated by two series of transplantation experiments: (1) The micronuclei from these cell lines were transplanted into normal amicronucleates. The resulting combination nevertheless uniformly exhibited the same kind of abortive autogamy. (2) Micronuclei from normal cells were transplanted into cells of the three abnormal cell lines; this yielded cell lines that were able to undergo normal autogamy. The two experiments thus demonstrated that the physical basis of the abortive autogamy in the three cell lines resided in defective micronuclei in these, and not in any other possible defect in other parts of the cells. Some considerations also indicated that the defects in such micronuclei only originated during or after transplantation into the amicronucleate recipients.View full abstractDownload PDF (411K) -
Yoshihiko FURUTA1981 Volume 56 Issue 3 Pages 287-294
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSSeventy three strains of Aegilops ovata L. collected in Jordan, Lebanon Syria, Turkey, Greece and Italy by The Botanical Mission of University of Kyoto to Eastern Mediterranean Countries were crossed with one common pollen parent and chromosome pairing at first metaphase of meiosis and pollen fertility of their F1 plants were observed.
Based on chromosome pairing, 73 strains were classified into four chromosome types, that is, (I) pollen parent type (one strain), (II) one reciprocal translocation type (55), (III) type with two independent reciprocal translocations (14) and (IV) type with two translocations involving three chromosomes (3).
From the frequency of quadrivalents, it is suggested that there are some kinds of reciprocal translocations in Ae. Ovata. It is revealed that no complicated chromosomal differentiation has occured in this species.View full abstractDownload PDF (476K) -
Sen-ichi ODA1981 Volume 56 Issue 3 Pages 295-299
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSMating experiments showed that the rolling gene, rol, causing abnormal locomotor activity was an allele of the tottering, tg, locus and that this locus was closely linked to the non-specific esterase-1 locus on chromosome no. 8. As a consequence, it is demonstrated that the tg locus has three mutant alleles; tottering, tg, leaner, la, and rolling, rol. The mice with genotype rol/tg show clinical symptoms similar to rol/rol rather than to tg/tg. The symptom of ataxia occurs at about two weeks of age in this mutant, which survives to the adult age.View full abstractDownload PDF (337K) -
Tomio MIYAMOTO, Makoto IKEBUCHI, Yasuhiro TERANISHI1981 Volume 56 Issue 3 Pages 301-308
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESSThe X-ray induction of the different kinds of dumpy mutations during spermatogenesis was investigated by using a wild type strain of Drosophila melanogaster, Canton-S. The results show that the yield of the olv and ov exceptions varies in the different germ cell stages, while this is not so for the ol, lv, o and v exceptions. This brood-mutation pattern for the ol and lv exceptions is quite different from that elucidated in scS1 B In49 sc8/BS Y sc8 males.View full abstractDownload PDF (358K) -
T. S. DHILLON, ELVERA K. S. DHILLON, ALFRED N. C. LAI, Y. Y. LAM, GLAD ...1981 Volume 56 Issue 3 Pages 309-314
Published: 1981
Released on J-STAGE: July 25, 2006
JOURNAL FREE ACCESS166 suppressor-sensitive (sus) mutants belonging to phages HK243, HKO22, and λ were analysed. N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)-in-duced mutants of all three phages showed a restricted distribution; a majority being of one or the other of two cistrons. Hydroxylamine (HA)-induced mutants of phage HKO22 were found to be randomly distributed over a number of cistrons but in the case of phage λ, out of 21 HA-induced mutants 10 were of cistron P and 6 of cistron R.View full abstractDownload PDF (245K)
- |<
- <
- 1
- >
- >|