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Volume 68 (1993)
- Issue 6 Pages 521-
- Issue 5 Pages 353-
- Issue 4 Pages 243-
- Issue 3 Pages 167-
- Issue 2 Pages 83-
- Issue 1 Pages 1-
Volume 68, Issue 2
Displaying 1-6 of 6 articles from this issue
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ARTICLES
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Hong-Seog PARK, Masa-Toshi YAMAMOTO1993 Volume 68 Issue 2 Pages 83-95
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSFree X duplication chromosomes of Drosophila melanogaster were synthesized by X-ray irradiating the In(1)scL8L sc8R chromosome which has a deletion in the distatl half of hA and the proximal half of hB of the centromeric heterochromatin. Fifty-nine duplications have been isolated and cytogenetically analyzed. They all carry wild-type allele of the yellow gene, y+, which should come from the distal tip of In(1)scL8Lsc 8R. They appear to be telocentric and predominantly heterochromatic. Majority of the duplications, especially in the classes MEDIUM and LARGE, can pair with XYL.YS in the male meiosis, indicating that they carry male meiotic pairing site(s) that is known to be located exclusively in the X heterochromatin. Complementation test in the males, Df(1)svr, v/Dp, y+, demonstrates that most of the duplications in the classes MEDIUM and LARGE carry euchromatin enough to cover the deletion. The portion of the euchromatin should be of the very proximal region close to the irradiated X chromosome centromere.
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Hirotami T. IMAI1993 Volume 68 Issue 2 Pages 97-118
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSBased on a schematic model of karyotype evolution, a new methodology for G-, R-, or Q-banding pattern analysis was investigated. Banding pattern analysis essentially depends on the unidirectional alteration and the randomness of the exchange sites of the AM-inversion. In karyotypes that evolved by AM-inversion and Robertsonian rearrangement, two matching patterns appear; (1) tandem and (2) complementary matching patterns. The former is characteristic of a single lineage sharing the same AM-inversions, and the latter appears in different lineages sharing different AM-inversions, by which it is theoretically possible to detect the ancestral karyotype and to reconstruct the karyotype phylogeny (cladogram). In contrast, the evolutionary pathway cannot always be perceived if karyotypes evolve only by Robertsonian rearrangement. The tandem matching pattern does not always mean tandem fusion, but can be interpreted as `tandem fission' by a combination of AM-inversion and centric fission. Tandem fusion and MM-inversion often cause entangled matching patterns, and thus they interfere with banding pattern analysis. Some methodological problems inherent in the conventional banding pattern analysis are highlighted, and suggested that such problems can be minimized by using the karyograph method. The methodology of banding pattern analysis proposed in the present paper will be applicable for matching the chromosome map of genetic markers among different species.
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Takashi YANAGISAWA, Shigemitsu TANO, Kiichi FUKUI, Kyuya HARADA1993 Volume 68 Issue 2 Pages 119-125
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSAn indirect immunofluorescence method detecting the incorporation of BrdU was applied to analyze the DNA replication pattern in soybean chromosomes which are very small among plant species so far examined. Discrete fluorescent images in the distal, interstitial and proximal regions of the chromosome arms were revealed at prometaphase. Time-course analysis indicated that the DNA replication starts at the distal region. The replication patterns are discussed in relation to other chromosomal characteristics such as the location of constitutive heterochromatin and the stainability with the Giemsa.
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Etsuko T. MATSUURA, Yuzo NIKI, Sadao I. CHIGUSA1993 Volume 68 Issue 2 Pages 127-135
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSWe previously reported a selective mode of mitochondrial DNA (mtDNA) transmission in mtDNA heteroplasmy that was induced artificially in Drosophila melanogaster; the transmission bias appeared to depend on the particular temperature at which heteroplasmic lines were maintained. Here we report investigations of the temperature-dependent mode of mtDNA transmission in heteroplasmic lines for intra- and interspecific combinations maintained separately at 22.5°C, 25°C and 29°C for 20 generations. We have examined a selection model for mitochondrial transmission, similar to genie selection in haploid organisms. Changes in the relative proportions of two types of mtDNA fit the expectations from the model well. The intensity of selection estimated as a selection coefficient depends on temperature. Temperature-sensitive processes thus appear to be involved in the transmission and maintenance of mitochondria.
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Marie SANDA-KAMIGAWARA, Sadao ICHIKAWA1993 Volume 68 Issue 2 Pages 137-145
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSAs a step to investigate the genetic identity of normal blue and mutant pink flower-color pigments in four different Tradescantia clones (BNL 02, KU 27, KU 9 and KU 20), which are heterozygous for flower color (blue/pink), the light absorption spectra of the normal blue and mutant pink cells in their stamen hairs were measured microspectrophotometrically. It was found that the blue cells of all the four clones showed the maximum absorption peak at 574 nm, the second peak at 618 nm, and a shoulder at around 544 nm. It was also found that the pink cells of all these clones had two absorption peaks at 546 and 586 nm and a shoulder at around 512 nm. These findings prove that all the four clones examined produce the identical blue-color pigment normally, and also the identical pink-color pigment when the dominant gene for the blue color underwent mutation. One leaky mutant (intermediately colored) hair cell of clone BNL 02 was shown to be producing both the blue- and pink-color pigments.
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Taihachi KAWAHARA1993 Volume 68 Issue 2 Pages 147-153
Published: 1993
Released on J-STAGE: November 02, 2004
JOURNAL FREE ACCESSThe genes responsible for three types of chlorosis found in hybrids between the Emmer and the Timopheevi group of tetraploid wheats were analyzed by test crosses. The presence of the complementary genes, Cs1 and cs1 in the Emmer group and Cs2s, Cs2m, Cs2w and cs2 in the Timopheevi group were confirmed. The frequency of Cs1 in the Emmer group was very low and none of the wild Triticum dicoccoides strains had Cs1. On the other hand, about half of the strains of the wild Timopheevi, T. araraticum, and all strains of the cultivated T. timopheevi had either Cs2s, Cs2m or Cs2w.
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