Inverted repeat

An inverted repeat (or IR) is a sequence of nucleotides that is the reversed complement of another sequence further downstream.

For example, 5'---GACTGC....GCAGTC---3'. When no nucleotides intervene between the sequence and its downstream complement, it is called a palindrome. Inverted repeats define the boundaries in transposons. Inverted repeats also indicate regions capable of self-complementary base pairing (regions within a single sequence which can base pair with each other).

Examples

 * original: 5'-GACTGC-3'
 * complement: 3'-CTGACG-5' (base pairing)
 * reverse complement: 5'-GCAGTC-3'
 * lac operator: 5'-AATTGT...ACAATT-3'