Sequence, intervening: An intervening sequence is the part of a gene that is initially transcribed from the DNA into RNA (specifically, 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 intervene between the exxons. Intervening sequences are also called introns. A gene is made up of an alternation of introns and exxons.