摘要
The natural reproduction of mammal is sexual reproduction, which needs fertilization involving sperm and oocyte. Nuclear transfer provided an asexual reproduction method for mammal. Donor cells used in previous experiments of nuclear transfer were mostly from undif-ferentiated or non-terminally differentiated cells, such as embryonic or fetal cells. However, since Wilmut et al. obtained a viable lamb by transfer of an adult sheep somatic cell into
The natural reproduction of mammal is sexual reproduction, which needs fertilization involving sperm and oocyte. Nuclear transfer provided an asexual reproduction method for mammal. Donor cells used in previous experiments of nuclear transfer were mostly from undifferentiated or non-terminally differentiated cells, such as embryonic or fetal cells. However, since Wilmutet al. obtained a viable lamb by transfer of an adult sheep somatic cell into an enucleated oocyte, nuclear transfer using adult somatic cell has been successful in several species. Wilmutet al. suggested that it was a key factor for the success of somatic nuclear transfer to induce the donor cells into GO phase (“GO-phase hypothesis”). In order to verify the Gophase hypothesis, nonquiescent adult fibroblasts from a bovine ear were transferred into enucleated bovine oocytes. The experiments showed that the rate of electrofusion after micromanipulation was above 50%, the cleaving rate was 54.5% and 9.1% of those reconstructed embryos developed to 32-cell stage. These results indicate that for cattle, nuclei from nonquiescent adult somatic cells introduced into enucleated oocytes are at least capable of supporting early development.
