Preimplantation mouse embryo: developmental fate and potency of blastomeres

During the past decade we have witnessed great progress in the understanding of cellular, molecular, and epigenetic aspects of preimplantation mouse development. However, some of the issues, especially those regarding the nature and regulation of mouse development, are still unresolved and controversial and raise heated discussion among mammalian embryologists. This chapter presents different standpoints and various research approaches aimed at examining the fate and potency of cells (blastomeres) of mouse preimplantation embryo. In dealing with this subject, it is important to recognize the difference between the fate of blastomere and the prospective potency of blastomere, with the first being its contribution to distinct tissues during normal development, and the second being a full range of its developmental capabilities, which can be unveiled only by experimental perturbation of the embryo. Studies of the developmental potential and the fate of blastomeres are of the utmost importance as they may lead to future clinical application in reproductive and regenerative medicine.