1989 Fiscal Year Final Research Report Summary
Genetic control of development in 2n/3n chimeric mouse embryos
| Project/Area Number |
62480080
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産学(含草地学)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TOYODA Yutaka Inst. Med. Res., Univ. Tokyo, Professor, 医科学研究所, 教授 (90050418)
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| Project Period (FY) |
1987 – 1989
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| Keywords | triploid / diploid / chimera / embryo / mouse / fertilization in vitro / chromosome / coat color |
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| Research Abstract |
Triploid embryos were developed from digynic ICR eggs fertilized with ICR or C57BL/6J spermatozoa in the presence of 5myg/ml cytochalasin B in vitro. About 60% of these tri pronuclear eggs developed into the blastocyst when.cultured in a modified Whitten medium supplemented with lOOmuM EDTA. At the eight cell stage, each of the triploid embryos was aggregated with a normal diploid ICR or FL(ICR x C57BL) embryos after removing their zona pellucida with pronase. The rate of development to a single blastocyst was 94.0% and 89.5% in the aggregated pairs of 2n(Fl)/3n(ICR) and 2n(ICR)/3n(Fl)embryos, respectively. The ratio of 2n:3n cells in these chimeric blastocysts was estimated to be about 4:6, based on the numbers of metaphase plates in karyotype analysis.
After transfer to the pseudopregnant recipients, 47.5% and 34.4% of 2n(Fl)/3n(ICR) and 2n(ICR)/3n(Fl) blastocysts were developed into viable young. Coat color chimerism was observed in 26.2% and 27.7% of the young derived from 2n(Fl)/3n(ICR) and 2n(ICR)/3n(Fl) embryos, respectively. These rates were significantly lower than that of control young derived from 2n/2n chimeric embryos. By karyotyping of cultured cells from the tail of coat color chimeras, it has been suggested that at least some of them were composed of both 2n and 3n cells, although the proportion of 2n cells was predominantly high.
All the offspring obtained from the chimeric mice showed the phenotype originated from diploid embryos, suggesting that the. germ cells were solely derived from the diploid cells in 2n/3n chimeras.
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