Figure 1
From: PILER-CR: Fast and accurate identification of CRISPR repeats
Structure of a CRISPR array. CRISPR repeats are perfectly (or almost perfectly) conserved short sequences, typically of length 20 to 40 bases, separated by unique sequences known as spacers. The spacer length in a given array is sometimes approximately conserved, varying by a few bases, and sometimes exactly conserved. The spacer length is typically similar to the repeat length.