ABSTRACT
The oocyte is a unique cell, not only in structure and function, but in that it is the only cell in the female body that undergoes meiosis, or a reductional division in chromosome number from a diploid to a haploid state. Meiotic progression in the oocyte is known as oocyte maturation and, simply defined, is the re-initiation of the first meiotic division, progression to metaphase II (MII), and the accompanying cytoplasmic processes necessary for successful fertilization and early embryo development1. This definition implies that oocyte maturation is, in fact, composed of two inter-related processes: nuclear and cytoplasmic maturation. This chapter will outline the process of oocyte maturation, as well as address the cellular and molecular mechanisms regulating the process with the understanding that, the better a system is understood, the better the chances of improving the manipulation of oocytes to support efficient in-vitro maturation (IVM) and/or preventing aberrations that occur in vivo. Such improvements hold great potential considering defects in oocyte meiosis are a leading cause of aneuploidy-derived infertility and birth defects2,3, as well as the immense potential benefits in-vitro oocyte maturation holds in
respect to treatment of human infertility and fertility preservation (see Parts III and IV).
