1998 Fiscal Year Final Research Report Summary
A Crossdisciplinary Study on the Benefits of Sexual Reproduction
| Project/Area Number |
09490010
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | University of Tokyo |
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Principal Investigator |
SHIMA Akihiko University of Tokyo, Graduate School of Frontier Sciences, Prof., 大学院・新領域創成科学研究科, 教授 (60011590)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Kenichi University of Tokyo, Graduate School of Sciences, Prof., 大学院・理学系研究科, 教授 (30150056)
FUJIWARA Haruhiko University of Tokyo, Graduate School of Sciences, Associate Prof., 大学院・理学系研究科, 助教授 (40183933)
MORI Takao University of Tokyo, Graduate School of Sciences, Prof., 大学院・理学系研究科, 教授 (80011659)
YAMAMOTO Masayuki University of Tokyo, Graduate School of Sciences, Prof., 大学院・理学系研究科, 教授 (40114706)
OHYA Yoshikazu University of Tokyo, Graduate School of Sciences, Associate Prof., 大学院・理学系研究科, 助教授 (20183767)
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| Project Period (FY) |
1997 – 1998
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| Keywords | sexual strategy / endocrine organ / sex chromosome / spermatogenesis / meiosis regulation genes / mate choice / pollen tube / germ cell mutation |
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| Research Abstract |
Wild type males or Females of the HNI strain of the medaka fish were exposed to gamma-rays and crossed to females or males of the non-irradiated tester medaka fish of the T5 strain. The total mutation rate of male germ cells of the HNI strain was about twice as high as that of female germ cells. We found two noble functions of VDE, an intein homing gene in Saccharomyces cerevisiae. This enables us to address the question how this selfish gene' was generated during evolution. We have demonstrated that specific RNA molecules and RNA-binding proteins play crucial roles in the promotion of meiosis in fission yeast and nematode. The Replication timing of active and inactive X chromosomes in primate species was analyzed. Y chromosome-specific repetitive sequences in prosimian species were also analyzed by molecular cytogenetic techniques. Formation of the fertilization tubule in Chlamydomonas was studied using a mutant lacking the conventional actin gene. The mutant was found to be unable to
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produce the fertilization tubule but express a large amount of a novel actin-like protein during mating. In order to carry out phylogenetic analyses of the colonial Volvocales using a large amont of nucleotide sequence data. PCR primers of atpB and psaB genes were developed. Based on the phylogenetic analyses of the combined sequence data set from these two genes and rbcL genes, evolutional sequences of sexual reproduction early in the evolution of the colonial Volvocales were inferred. The aim of this study is to find the generality of microtubule formation among higher organisms. To this aim, we have established a system, in which microtubule is organized from the fraction that has been prepared from plant cells. In this system, we have identified that upon this organization, gamma-tubulin, EF1 alpha and other novel proteins are involved. In established of sex difference of chicken embryo gonads, luteinizing hormone was shown to be a pivotal factor for estrogen secretion, and estrogen could induce the female type of sex. The behavior of organelle nuclei during sperm cell formation, especially the regulation of increase/decrease of organelle DNA in young generative cells just after pollen mitosis I, is important in determining the pattern of cytoplasmic inheritance (maternal, biparental, or maternal) in higher plants. We studied wing morphogenesis associated with sex differentiation of insect. We found that the loss of wings of female moth that has no wings naturally is induced by a steroid hormone, ecdysone. Epidemiological analyses of the HTLV/STLV in humans and monkeys, respectively, suggested the virus exploits the host, especially female, reproductive processes to survive. A model of sexual selection by male choice in a monogamous population was developed and applied to the evolution of human skin color. The possibility of negative assortative mating for HLA type among Japanese was tested, but the null hypothesis of random mating could not be rejected. Less
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