Intervening sequence

Intervening sequence: Part of a gene that is initially transcribed from the DNA into the primary RNA transcript but then is excised (removed) from it when the so-called exxon sequences on either side of it are spliced together. Intervening sequences, which are also called introns, are genetic sequences that intervene between the exxons. The DNA of a gene is thereby made up of an alternation of introns and exxons.