Regulation of these structures is the primary function of RNA complexes formed from piwi-interacting RNA. A group of these structures that uses a mechanism (15[1])similar to rolling circle replication are called helitrons. (15[1]-5[2])An unusually (15[1])high (-5[1])amount of these structures are found in Trichomonas vaginalis, (-5[1])which also has the Mariner type of these structures. (-5[1])LINEs and SINEs are (15[1])two classes (15[2])of these structures, (15[2])the latter (15[1])of (15[1])which includes the widespread (15[1]-5[1])(*) Alu (10[1])element. (-5[1])Knockout (10[1])rats (10[2])are often produced (10[1])with the Sleeping Beauty system of these structures. (10[2])The Ac/Ds system in corn uses class 2 examples of these structures, which use (10[1])a “cut-and-paste” (10[1])mechanism. (-5[2])For 10 points, (10[1])name these genetic (-5[1])sequences (-5[2])discovered (-5[1])by (-5[1])Barbara (10[3])McClintock, (10[8])which (10[1])can (10[2])move around a (10[1])genome. (10[6])■END■ (10[9]0[7])