Practice question

Isocaudomers are pairs of restriction enzymes that recognize different target sequences yet generate identical cohesive overhangs after cleavage, allowing ligation of fragments produced by either enzyme. This property enables versatile cloning when one site is absent. BamHI recognizes G^GATCC and BglII recognizes A^GATCT, both leaving a 5' GATC overhang. Despite distinct six-base recognition sites, the single-stranded extensions are perfectly complementary and mutually ligatable, so fragments can be joined and the hybrid site often becomes resistant to both enzymes. This compatibility is exploited for forced cloning and vector construction.