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Type Ⅱ restriction endonucleases (REases) cleave double-stranded DNA at specific sites within or close to their recognition sequences.Shortly after their discovery in 1970,REases have become one of the primary tools in molecular biology.However,the list of available specificities of Type Ⅱ REases is relatively short despite the extensive search for them in natural sources and multiple attempts to artificially change their specificity.