Figure 1. Generalized scheme for the production of chimeric porcine blastocysts and fetuses by the aggregation method.

For in vitro analysis of the chimeric blastocyst formation, donor ICMs were isolated from parthenogenetic blastocysts derived from IVM oocytes. Isolated ICMs stained with DiI were aggregated with blastomeres isolated from parthenogenetic host embryos in a microwell made on the bottom of a culture dish. For in vivo analysis of chimeric fetus formation, the donor ICMs were isolated from blastocysts fertilized in vitro by transgenic boar sperm carrying the fluorescent huKO gene. ICMs of the IVF blastocysts were similarly aggregated with the parthenogenetic host embryos as the DiI-stained ICMs, and the resultant blastocysts were transferred to recipient pigs to obtain chimeric fetuses.