gene expression
Meaning of gene expression: Gene expression is the multistep process converting a gene's DNA sequence into RNA and, often, a functional protein, and its level can be measured directly.
Definition of gene expression
Gene expression is the process by which the information stored in a gene is used to produce a functional product, typically a protein, within a cell. The process begins with transcription, in which the DNA sequence of a gene is copied into a molecule of messenger RNA.
The messenger RNA then typically undergoes translation, in which the cell's protein making machinery reads its sequence and assembles the corresponding protein. Not every gene is expressed at the same time or to the same degree, and cells regulate gene expression through numerous mechanisms, allowing different cell types to use the same genetic code to produce very different sets of proteins.
Gene expression can be measured in several ways, including quantifying the amount of a gene's messenger RNA, measuring the resulting protein directly, or observing what that protein does within a cell. Changes in gene expression underlie normal processes such as development and the body's response to its environment, as well as the abnormal growth seen in cancer.
Used in a sentence
The study compared gene expression patterns between the tumor tissue and adjacent normal tissue.
Good to know
Gene expression can be measured at the level of RNA or protein, and these two types of measurement do not always agree, since a gene's RNA can be produced without necessarily being fully translated into a corresponding amount of protein.
Word origin
Where “gene expression” comes from
Formed from Greek genos, meaning birth or race, the root of gene, combined with Latin exprimere, meaning to press out, the root of expression.