I-motifs are what scientists call "dynamic" — they can fold and unfold depending on the pH (or acidity) of their surroundings. In addition, the sequences that code for i-motifs are generally found not within a gene itself, but a little upstream, in a part of the genome known as the promoter region that determines whether or not a certain gene gets expressed.

Source: Los Angeles Times April 23, 2018 15:00 UTC