ABSTRACT
In the present chapter, the authors describe attempt to improve the efficiency of gene incorporation in the bovine, by injecting oocytes and zygotes at different stages of the cell cycle, by following the fate of the foreign DNA in treated embryos with regard to the time of injection of the zygotic replication phase, by exploiting the principle of restriction endonuclease-mediated integration demonstrated in other organisms, and finally by flanking the transgenes with highly repeated endogenous genomic regions. Injection of cloned DNA into ova and zygotes has been used to examine the expression of a reporter gene under the control of different promoters. Few studies describe the molecular events involved in chromosomal integration of foreign DNA. In conclusion, in all experiments using different systems for foreign gene transport into germ cells, DNA incorporation into the transformed cells was demonstrated.
