Proteomics, transcriptomics and genomics

Proteomics is the large-scale study of proteomes. A proteome is a set of proteins produced in an organism, system, or biological context. We may refer to, for instance, the proteome of a species (for example, Homo sapiens) or an organ (for example, the liver). The proteome is not constant; it differs from cell to cell and changes over time. To some degree, the proteome reflects the underlying transcriptome. However, protein activity (often assessed by the reaction rate of the processes in which the protein is involved) is also modulated by many factors in addition to the expression level of the relevant gene.

Genomics is the large-scale study of the genome which is the entirety of the genes found in the nucleus of each cell within an organism. The genome is inherited but each individual has a unique combination of parental genes. The genome itself is a unique and specific set of genes replicated within an organism but its expression differs between cells in different parts of the body and can change over time and in response to external stimuli. Gene expression is controlled in multiple complex ways but is also regulated by epigenetic processes which ‘switched on and off’ the expression of genes in response to chemical and environmental conditions via a process of methylation.