Somatic cell clone technology is a viable ap- proach to preserving endangered livestock and wildlife ge- netic resources. In the present research, somatic cell nuclear transfer (SCNT) was performed using granulose cells from the critical endangered Chinese red-cross yellow cattle as donor cells. A total of 211 oocytes were manipulated and 166 (79%) of them were successfully enucleated. 112 (67.4%) SCNT embryos were reconstructed, 94 (83%) of them cleaved, and 48 (43%) of them developed to blastocyst stage. SCNT blastocysts were transferred to 6 Holstein recipients, and 2 (33%) of them were found to be pregnant. One of them maintained to term and delivered a calf, whereas another aborted. Effect of different fusion buffer (mannitol vs. Zim- merman fusion buffer) and different activation methods (calcium ionophore+6-DMAP vs. cycloheximide+CB) on fu- sion rate and development of SCNT embryos were investi- gated. The results indicated that: (i) on condition of two DC pulses of 2.5 kV/cm for 10 μs each, fusion rates were higher in mannitol solution than in Zimmerman fusion buffer (71% vs. 61%, respectively, p<0.05), but the blastocysts rates did not differ between two treatments (36% vs. 39%, p>0.05 ); (ii) There was no significant difference in development rates to the blastocyst stage for SCNT embryos activated by calcium ionophore+6-DMAP or by cycloheximide+CB (42% vs. 46%, respectively, p>0.05). Microsatellite DNA analysis examining 28 loci confirmed that the cloned calf was genetically identi- cal to the donor Jinan red-cross yellow cattle and different from the recipient females. Growth and reproductive per- formance of cloned cow were evaluated, and there were no difference i cross-red n it between cloned and normal control Jinan yellow cattle. Furthermore, the cloned yellow cow has delivered a healthy yellow calf.
DAI YunpingLIAN ZhengxingZHU HuabinGONG GuochunWANG LiliWANG HaipingZHAO ZhihuiZHU QinghongFEI JingLI Ning
