ABSTRACT
Large-scale analyses of gene expression during human oogenesis and embryogenesis has been hampered by a scarcity of material for analysis coupled with a lack of highly sensitive investigational tools. Historically, a variety of classical molecular techniques have been employed to examine cellular mRNA levels.1-3 However, these methods were generally crude in nature and thus lacked the precision to accurately and reproducibly detect or quantify transcripts in single cells. Reverse transcriptionpolymerase chain reaction (RT-PCR) provided a highly sensitive means to distinguish rare mRNA species in individual cells.4 Together with fluorescent dyes, RT-PCR can now be used to reliably quantify gene expression in individual oocytes.5,6
Subsequently, PCR-based methods, and, more recently, analysis tools that provide genome-wide perspectives such as microarray techniques have been used to glean a wealth of knowledge regarding the global expression profile of the oocyte and embryo.7-9 However, a great deal of work remains to be done in order to fully dissect the complex regulatory pathways that direct early human development. This chapter reviews our current understanding of these developmental programs.
