ABSTRACT
In order to research developmental competence of transgenic somatic cell by serial nuclear transplantation, goat cloned embryos were compared with recloned embryos in ability of in vitro development. Fetal fibroblasts including human finger-domain lacking t-PA gene was microinjected into cytoplasm of the MII oocytes. Goat embryos (G0) were cloned by this procedure. A single blastomere from 16 - 64-cell goat cloned embryos (G0) was microinjected into Intracytoplasm of the MII oocytes. Goat embryos (G) were cloned by this procedure. Goat embryos (G2, G3) were recloned by using 16 - 64-cell recloned embryos. The developmental time of donor embryo affected the developmental rate of recloned embryos (G1, G2). The results show: the cleavage rate of cloned embryos (G0) (76.45% +/- 1.17%) was no difference significantly with recloned embryos (G1 G2 G3) (72.18% +/- 1.97%, 76.05% +/- 2.38%, 75.99% +/- 2.84%); the developmental rate of morulae and blastocysts of cloned embryos (47.20% +/- 2.93%, 11.00% +/- 1.42%) were higher than these of recloned embryos(34.99% +/- 2.66%, 28.23% +/- 2.00%, 23.34% +/- 1.99%) (3.87% +/- 0.67%, 2.08% +/- 1.66%, 0); the morulae rate(29.57% +/- 1.53%, 24.43% +/- 1.87%) and blastocysts rate(1.96% +/- 1.31%, 2.01% +/- 1.34%) of recloned embryos (G1 G2) from 16-cell recloned embryos were lower than those(34.32% +/- 1.31%, 29.76% +/- 1.66% and 3.86% +/- 1.03%, 3.48% +/- 0.34% )from 32 - 64-cell recloned embryos (P > 0.05). In conclusion, nuclear transfer embryos should not were recloned mostly; and the embryos recloned by using 32 - 64-cell embryos achieved higher developmental ability compared with using 16-cell embryos.