A genome sequence is, by itself, of limited use. Merely knowing the sequence would be like having a huge set of encyclopedias without being able to read: you could recognize the different letters, but the text would be meaningless. Functional genomics characterizes what sequences do—their function. The goals of functional genomics include the identification of all the RNA molecules transcribed from a genome, called the transcriptome of that genome, and all the proteins encoded by the genome, called the proteome. Functional genomics uses both bioinformatics and laboratory-based experimental approaches in its effort to define the function of DNA sequences.