A gene encoding protein is a DNA region that determines the amino acid sequence of one protein. Gene expression is the process in which genetic information is used for protein synthesis. Genetic information consists of nucleotide (base) sequences on a DNA strand, and this information is transcribed into messenger RNA (mRNA) sequences. Thus, mRNA is synthesized using DNA as a template. The genetic code contained in mRNA is used for protein synthesis by cytoplasmic granules called ribosomes. While we mainly examine the process of transcription by which cells copy the genetic information contained in DNA into mRNA, it is worth noting that the process for synthesizing RNA other than mRNA (i.e., non-coding RNA, ncRNA) also uses DNA as the template for expressing ncRNA genes.

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