Genes & Genetic Systems
Online ISSN : 1880-5779
Print ISSN : 1341-7568
ISSN-L : 1341-7568
73 巻, 5 号
選択された号の論文の7件中1~7を表示しています
Full Papers
  • Man Kyu Hur, Hong Wook Huh
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 275-280
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    Enzyme electrophoresis was used to estimate genetic diversity and population structure of Chimaphila japonica Miquel in Korea. The percent of polymorphic loci within the enzymes was 66.7%. Genetic diversity at the species level and at the population level was high (Hes = 0.279; Hep = 0.256, respectively), whereas the extent of the population divergence was relatively low (GST = 0.086). FIS, a measure of the deviation from random mating within the 16 populations, was 0.374. An indirect estimate of the number of migrants per generation (Nm = 2.65) indicates that gene flow is high among Korean populations of the species. In addition, analysis of fixation indices revealed a substantial heterozygosity deficiency in some populations and at some loci. Mean genetic identity between populations was 0.973. It is highly probable that directional toward genetic uniformity in a relatively homogenous habitat is thought to be operated among Korean populations of C. japonica.
  • Mi Yoon Chung, Gae Min Chung, Myong Gi Chung, Bryan Epperson
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 281-285
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    The fine-scale population genetic structure of Cymbidium goeringii (Orchidaceae), a small herbaceous perennial, was analyzed using spatial autocorrelation statistics. All visible individuals (138 and 110, respectively) within 20 × 40 m areas of each of two populations were sampled and their locations were mapped. Individual plants were genotyped for 14 allozyme loci, and Moran's spatial autocorrelation statistics were calculated for a large numbers of alleles. Values of Moran's I-statistics were statistically significant in 35 (19.4%) to 36 (16.4%) of 180 and 220 cases respectively for the two populations, and the overall correlograms were significant for 11 (61.1%) to six (27.3%) of 18 and 22 alleles, respectively.
    The results also indicate that genetic similarity was shared among individuals within up to a scale of 14 m distance, and this is partly due to a combination of limited pollen dispersal and long distance seed dispersal by wind. One important implication is that, from the viewpoint of conservation genetics, sampling within populations should be conducted at 14-16 m intervals in order to optimize the genetic diversity in collections from population.
  • Ling Zhi Xiao, Sadao Ichikawa
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 287-292
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    Mutagenic interaction between ethyl methanesulfonate (EMS; a monofunctional alkylating agent) and maleic hydrazide (MH; a promutagen activated into a mutagen in plants highly likely by peroxidase) was studied in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. Since EMS has been shown to act synergistically with X rays in inducing mutations, and mutagenic synergisms have also been observed between X rays and MH by exposing to X rays before MH treatments, EMS and MH were expected to act synergistically at least by exposing to EMS before MH treatment. Three different combined treatments were conducted, i.e., by exposing for 4 h to 18.8 mM EMS 44 or 20 h before starting or 20 h after completing 1 mM MH treatments for 4 h. Unexpectedly, however, clear antagonistic effects in inducing somatic pink mutations were detected after all these combined treatments. Especially, the induced mutation frequency by exposing to EMS 44 h before the MH treatment was significantly lower than that induced by MH alone. The clear mutagenic antagonisms observed were thought to have resulted from EMS-caused inhibition of activation of MH by peroxidase, EMS ethylating and thus inactivating this enzyme or its precursors. Decreased peroxidase activities than those after treatments with MH alone were measured after two combined treatments, i.e., 12 h after the one exposing to EMS 44 h before MH and 24 h after the other exposing to EMS 20 h after MH, but the decreases were not large enough or their fluctuations were too large to judge them to be statistically significant. Comparisons of mutation frequencies induced by the combined treatments exposing to EMS before MH with those by MH alone suggest that there are some mechanisms (other than ethylation of peroxidase or its precursors) by which EMS suppresses the activation of MH.
  • Heui-Soo Kim
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 293-296
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    The human cts18.1 gene has high homology with the cytohesin gene family. By PCR analysis of a human monochromosomal somatic cell hybrid DNA panel, the cts18.1 gene was localized to chromosome 19. Diversity values of synonymous and nonsynonymous substitutions indicate that negative selection has occurred in the pleckstrin-homology (PH) domain of the cytohesin gene family. The phylogenetic tree calculated by the neighbor-joining method suggests that cts18.1 and cytohesin-2 genes are more closely related to each other than either of them is to the CLM-2 gene in the analysis of cDNA of the PH domain.
  • Tsuneo Sasanuma, Naohiko T. Miyashita
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 297-309
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    To investigate genetic mechanisms acting on multigene family in plants, we analyzed sequence variation in the rbcS gene of 13 species of Triticeae and one species each of related tribes (Bromeae and Aveneae). A total of 36 rbcS genes were analyzed. Based on dimorphism in the length of intron, the rbcSs of investigated species were classified into two subfamilies A and B. The difference in intron length was caused by an indel of about 200 bp in the middle of the intron. The two subfamilies of rbcS were present in the three tribes, indicating that the divergence of rbcS subfamilies occurred before the split of these tribes. Generally, variation between the two subfamilies of rbcS was larger than that within subfamily, but these two measures were about the same at the tribe level. This result suggested that divergence of the subfamilies of rbcS occurred at about the same time of tribe diversification. The level of nucleotide variation in the exon region between subfamilies was reduced in the Triticeae, but clear change was not detected in the intron sequence. This result suggested that the exon sequences between subfamilies of rbcS were homogenized without affecting the intron sequence in the Triticeae lineage.
  • Masayoshi Shigyo, Kenzi Imamura, Mitsuyasu Iino, Ken-ichiro Yamashita, ...
    原稿種別: Full papers
    1998 年 73 巻 5 号 p. 311-315
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    Genomic in situ hybridization (GISH) was used to identify alien chromosomes in a series of eight different Allium fistulosum - A. cepa monosomic addition lines. Biotin-labeled total genomic DNA from shallot (A. cepa L. Aggregatum group) was used as a probe together with an excess amount of unlabeled blocking DNA from the recipient plant, Japanese bunching onion (A. fistulosum L.). Probe hybridization sites were detected by FITC-conjugated avidin and anti-avidin antibody using an epifluorescence microscope. In each mitotic metaphase cell of all the eight types of monosomic addition lines, the alien chromosomes were successfully discriminated from other 16 A. fistulosum chromosomes. Furthermore, no clear exchanges of chromosome segments between A. cepa and A. fistulosum were observed. This finding indicates that in each addition line an entire (unrecombined) A. cepa chromosome is present in an integral diploid background of A. fistulosum.
Short Communications
  • Kazunari Hashiguchi, Takaji Ikushima
    原稿種別: Short Communications
    1998 年 73 巻 5 号 p. 317-321
    発行日: 1998年
    公開日: 2002/11/06
    ジャーナル フリー
    The partial nucleotide sequences of mitochondrial 16S rRNA gene were analyzed in five rodent cell lines, prior to the analysis of mutation spectrum in the gene. Total DNA was isolated from V79 and CHO-K1 cell lines from Chinese hamster and murine cell lines, Balb Y SV and PCC4 AG Cap, and the 3' terminal regions including the peptidyl transferase domain which is the target for chloramphenicol, a selective inhibitor of mitochondrial protein synthesis, were amplified by polymerase chain reaction (PCR) using two sets of primers and directly sequenced. In Chinese hamster cells, C to T transition at one site was observed in CHO-K1, and either A was deleted at the sequence of AA in all three cell lines, relative to the V79-cell sequence registered in GenBank. One G to A transition mutation in heteroplasmic state was observed in mouse PCC4 AG Cap cells which have chloramphenicol resistant phenotype, whereas there was no change in the Balb Y SV cell line, relative to the L-cell sequence. These mutation sites were located outside the peptidyl transferase domain.
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