Production of bovine tetraploid embryos by electrofusion and their developmental capability in vitro.

Optimal conditions of electrofusion for blastomeres of two-cell bovine embryos to produce tetraploid embryos were investigated. The high fusion rate (73-95%), viability, and developmental capacity were obtained under a field strength of 1.0 kV/cm with direct current pulses of 10 or 25 microseconds duration applied twice. Cytological study showed that 78.6% (11/14 embryos) of embryos exposed to electrofusion had tetraploid chromosome sets and the others were diploid or hexaploid. The tetraploid embryos had the capability to develop up to morulae stage in vitro.