Figure 1.

Procedure for production of cloned transchromosomic bovine (TcB). Cloned TcB is accomplished by employing microcell‐mediated chromosomal transfer to introduce a human artificial chromosome (HAC) vector containing the entire unrearranged sequences of the human immunoglobulin heavy‐chain (H) and lambda (λ) light‐chain loci into bovine primary fetal fibroblasts through microcell‐mediated chromosome transfer. Tc fibroblasts and enucleated oocyte couplets are fused, resulting in the transfer of the fibroblast nucleus and the formation of an embryo. The reconstituted Tc embryos were cultured in vitro to the blastocyst stage and then implanted into recipient cows.