Abstract. We have found direct DNA repeats 21-47 bp in length interspersed with nonrepetitive sequences of similar length, or clustered regularly interspaced short palindromic repeats (CRISPRs) in a wide range of diverse prokaryotes, including many Archaeal and Eubacterial species. A number of cas, CRISPR-associated genes have also been characterized in many of the same organisms. Phylogenetic analysis of these cas genes suggests that the CRISPR loci have been propagated via HGT, horizontal gene transfer. We suggest a mechanism by which this HGT has occurred, namely, that the CRISPR loci can be carried between cells on megaplasmids ‡40 kb in length.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.