| Project/Area Number |
60540415
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
遺伝学
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| Research Institution | Institute for Developmental Research, Aichi Prefectural Colony |
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Principal Investigator |
SONTA Shin-ichi Department of Genetics, Institute for Developmental Research, Aichi Prefectural Colony, その他, 研究員 (00100165)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Chromosom Abnrimality / Embryogenesis / Monosomy / Chinese Hamster / 相互転座 |
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| Research Abstract |
The gametic and zygotic selection of genome imbalance was investigated by direct chromosome analyses of spermatocytes and preimplantation embryos in translocation heterozygous system of the Chinese hamster.
First, all karyotypes expected from MII observation in male translocation heterozygotes were found in the first cleavage metaphase of zygotes from the crosses +/+ <+!゜> x T/+ <^!゜> . Second, there was no difference in the frequency of zygotes cleaved to a 2-cell embryo between in the experimental crosses (+/+ <+!゜> x T/+ <^!゜> ) and in the control cross (+/+ <+!゜> x +/+ <^!゜> ). Specific karyotypes observed at the first cleavage in the experimental crosses +/+ <+!゜> x T3/+ <^!゜> and +/+ <+!゜> x T7/+ <^!゜> (or T8/+ <^!゜> ) were no longer seen after the second and the fourth cleavage, respectively. The frequencies of zygotes with these karyotypes at the first cleavage metaphase were nearly consistent with the rates of 2-cell and 8-cell embryos at the blastocyst stage in the respective cross. The karyotypes lost after second cleavage in the cross of T3/+ and after the fourth cleavage in the cross of T7/+ <^!゜> (or T8/+ <^!゜> ) had commonly a deficiency of the segments of chromosome 2 and chromosome 1, respectively. These findings reveal that embryos with specific karyotypes having a deficiency of the chromosome cease cleavage at such early stages and hence are eliminated before implantation. Third, among day 4 embryos karyotyped successfully, some embryos in chromosomally unbalanced condition showed a tendency to have a small number of blastomeres in embryos mainly with a deficiency of the chromosomes was significantly smaller than that of embryos from the control cross. The finding revealed that some embryos with a deficiency delayed cleavage before the blastocyst stage.
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