Temporal expression of marker transcripts: Key to successful maturation and development of mammalian oocytes

In vitro embryo production (IVEP) is one of the tool to gain rapid genetic improvement in livestock besides its use in conservation of endangered species. IVEP provides necessary starting material for the basic research in animal development, embryo genomics and stem cells. The success of IVEP depends upon several major factors such as quality of oocyte and sperms, type of culture medium, culture conditions etc. In vitro produced embryos differ substantially from in vivo derived embryos in the mRNA expression patterns of genes important for development. As female germplasm (oocyte) is more valuable when compared to male germplasm (sperm) because of scanty availability and relatively fixed number, it is essential to maintain quality of oocyte in IVEP. Oocyte maturation is an inevitable step towards successful IVEP as the process of maturation is still not clearly revealed, it is essential to identify temporal expression pattern of marker genes involved during maturation process for production of developmentally competent embryos. Mammalian models can provide better insight into the oocyte maturation mechanism. This review focuses on the various marker genes which are essential for successful maturation of mammalian oocyte and are key regulators in deciding the fate of oocytes for production of developmentally competent embryos.