ABSTRACT
The technique of selective destruction of individual blastomeres suffers from the obvious limitation that only some of the original blastomeres are available for study. Investigations aimed at studying the developmental potential of each individual blastomere of a cleaving embryo necessitate the removal of the zona pellucida, so that the blastomeres may be completely separated. The mouse embryo, which will undergo complete preimplantation development in vitro, has lent itself readily to experiments involving radical micromanipulations. The micromanipulation of cleaving embryos of the large domestic species is of interest both with a view to confirming or establishing basic mechanisms of development and differentiation and with a view to exploiting for practical purposes the developmental potential and regulatory capacity of blastomeres. The possibilities of transferring two monozygotic embryos to two different recipients, and of storing embryos with a view to the production of monozygotic animals of differing age, further add to the practical value of the techniques.
