Gene expression
When a gene is expressed, it is first transcribed (DNA → mRNA) and the mRNA is then translated into a protein. Not all genes in the genome are expressed in all cells or tissues, because the need and function of various cells or tissues differ. Therefore, the consequences of a gene mutation will primarily affect tissues relying on and expressing that specific gene. Techniques for detecting gene expression are for example, northern blot, quantitative PCR, and microarray.