Intron

A noncoding DNA sequence within a gene that is initially transcribed into messenger RNA but is later snipped out. See Coding, DNA, Messenger RNA, Transcription.

A segment of the primary transcript of a eukaryotic gene, removed (before the mature mRNA is translated) in a process known as intron splicing. Some eukaryotic genes contain a large number of introns, which make up the bulk of the DNA sequence of the gene. Introns are also found in genes whose RNA transcripts are not translated, namely eukaryotic rRNA and tRNA genes. In these cases the intron sequence does not appear in the functional RNA molecule. Synonym: intervening sequence.

A noncoding sequence of DNA that is initially copied into RNA but is cut out of the final RNA transcript. See also gene, chromosome

DNA sequence that interrupts the protein-coding sequence of a gene; an intron is transcribed into RNA but is cut out of the message before it is translated into protein. See also: exon