Transcriptome characterization through the generation and analysis of expressed sequence tags: Factors to consider for a successful EST project

Sequencing of expressed sequence tags (ESTs) has been one of the primary techniques used for transcriptome analysis in a wide spectrum of species including those utilized for aquaculture. However, many researchers are still unfamiliar with the many genome applications and byproducts of EST analysis, and they often regard ESTs as only short random sequences. Additionally, lack of cDNA library normalization, project planning, and quality control have often restricted the value of EST resources created in many laboratories. This review aims to address these issues by providing information on the construction of normalized cDNA libraries for efficient generation and analysis of ESTs and by highlighting the significance of EST analysis for the genome research of species lacking a sequenced genome. A successful EST project can provide the sequence tools needed for not only gene discovery, but also for physical, linkage and comparative mapping, analysis of alternative splicing and gene duplication, and microarray development.