Clustered regularly interspaced short palindromic repeats (CRISPRs) are a family of DNA direct repeats found in many prokaryotic genomes. This family of proteins corresponds to Cas1, a CRISPR-associated protein. Cas1 may be involved in linking DNA segments to CRISPR [2].

1: A guild of 45 CRISPR-associated (Cas) protein families and multiple CRISPR/Cas subtypes exist in prokaryotic genomes. Haft DH, Selengut J, Mongodin EF, Nelson KE; PLoS Comput Biol. 2005;1:e60. PMID:16292354

2: Clustered regularly interspaced short palindrome repeats (CRISPRs) have spacers of extrachromosomal origin. Bolotin A, Quinquis B, Sorokin A, Ehrlich SD; Microbiology. 2005;151:2551-2561. PMID:16079334