This chapter will exhibit and summarize current molecular biotechnologies that focus on characterizing gene expression at the mRNA level. Specific focus will be on recent research regarding marine ecosystems and organisms. Learning objectives for the advanced biology students are the following:

• To understand the similarities and differences between genomics (DNA-based) and transcriptoics (RNA-based) laboratory methods for data generation and analysis.
• To learn the strengths and weaknesses of various state-of-the-art transcriptomic methods that are used to study gene expression and mRNA transcripts, and when they can be most appropriately applied.
• To rate and apply the most cost-effective means for transcriptome analyses based on the model system and hypotheses posed.