Abstract：Abstract: mitochondrial is the only organelle containing extranuclear genetic material in mammal cell, which proper function required extensive nuclear-mitochondrial interactions. Mitochondrial DNA(mtDNA) encodes some kinds of subunits of respiratory chain enzymes, tRNAs and rRNAs; other hundreds of mitochondrial components are encoded in the nucleus. The heteroplasmic somatic nuclear transfer possibly causes mtDNA heteroplasmic phenomenon in reconstructed embryos. In the present study, applying the method of PCR-restriction fragment length polymorphism(PCR-RFLP),examination of the mtDNA origin and proportion in reconstructed embryos derived from goat fetal fibroblasts and enucleated sheep MⅡoocytes was performed. The result shows that, the proportion change of nuclear donor to recipient mtDNA is not big, the proportion of nuclear donor to recipient mtDNA in 1-cell,2-cell,4-cell and 8-cell reconstruction embryos is 2.5±0.8%; 2.8±0.6%; 1.9±0.4%; 1.7±0.6% separately and the difference is not significant (p> 0.05), however, in the heteroplasmic blastocysts, the proportion of nuclear donor mtDNA declined to 0.3±0.1%,and the difference is significant (p< 0.05).
