The transcriptome is the set of all RNA molecules, including mRNA, rRNA, and tRNA, that are produced in one or more cells. RNA molecules are transcribed from DNA, and the transcriptome includes both coding and non-coding RNAs. The term “transcriptome” can also refer to the complete set of proteins encoded by a genome.
The transcriptome is important for two main reasons: first, it represents the gene products that are available for use at any given time in a cell or tissue; second, changes in transcript abundance (expression) can provide insights into gene function. For example, if a particular gene is differentially expressed between two tissues (e.g., brain and liver), this may suggest that the gene plays a different role in each tissue. Transcriptomics has been used to study various aspects of biology, including developmental processes, disease pathogenesis, and evolutionary relationships.
In recent years, next-generation sequencing technologies have drastically increased our ability to measure transcriptomes. These technologies allow for the simultaneous sequencing of millions of RNA molecules (known as “deep sequencing”), providing unprecedented coverage of the transcriptome. As a result, transcriptomics has become an important tool in many areas of research.