Abstract
Intracytoplasmic injection of a donor cell into an enucleated bovine oocyte was used to determine the in vitro and in vivo developmental capability of bovine cells derived from late morula-stage embryos. A single cell from late morula-stage embryos was directly injected into an enucleated activated oocyte cytoplasm. Development rates of nuclear transfer embryos to the 2- to 8-cell, morula, and blastocyst stages were 43.3 (13/30), 16.7 (5/30) and 6.7% (2/30) respectively. The viability of the nuclear transfer embryos was confirmed by the birth of a normal calf after transferring them into a recipient cow. The results indicated that the direct injection of a single cell into an enucleated activated oocyte may be an alternative to the oocyte-cell fusion method currently used for bovine nuclear transfer.
