Editing Repeated sequence (DNA) (section)

=== Direct and inverted repeats ===
While tandem and interspersed repeats are distinguished based on their location in the genome, direct and inverted repeats are distinguished based on the ordering of the nucleotide bases. [[Direct repeat]]s occur when a nucleotide sequence is repeated with the same directionality. [[Inverted repeat]]s occur when a nucleotide sequence is repeated in the inverse direction. For example, a direct repeat of "CATCAT" would be another repetition of "CATCAT". In contrast, the inverted repeated would be "ATGATG". When there are no nucleotides separating the inverted repeat, such as "CATCATATGATG", the sequence is called a palindromic repeat. Inverted repeats can play structural roles in DNA and RNA by forming stem loops and cruciforms.<ref>{{cite journal | vauthors = Pearson CE, Zorbas H, Price GB, Zannis-Hadjopoulos M | title = Inverted repeats, stem-loops, and cruciforms: significance for initiation of DNA replication | journal = Journal of Cellular Biochemistry | volume = 63 | issue = 1 | pages = 1–22 | date = October 1996 | pmid = 8891900 | doi = 10.1002/(SICI)1097-4644(199610)63:1<1::AID-JCB1>3.0.CO;2-3 | s2cid = 22204780 | eissn = 1097-4644 }}</ref>