An in vitro method for DNA fragmentation and tagging of a target DNA molecule, said method comprising: combining: a first DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for a transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase; a second DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for the transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase, wherein the non-recognition portion of the sequence is different from the non-recognition portion sequence of the first DNA molecule; and the transposase, wherein the transposase is a transposase from Vibrio harveyi and wherein combining the three substances allows them to interact; and combining the interacted substances with a target DNA molecule and Mn +2 ions under conditions whereby the interacted substances associate with the target DNA and cleave the target DNA molecule via transposase-mediated cleavage to provide a cleaved DNA product wherein the Mn +2 concentration is between about 1 mM and about 100 mM. combining: a first DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for a transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase; a second DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for the transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase, wherein the non-recognition portion of the sequence is different from the non-recognition portion sequence of the first DNA molecule; and the transposase, wherein the transposase is a transposase from Vibrio harveyi and wherein combining the three substances allows them to interact; and combining the interacted substances with a target DNA molecule and Mn +2 ions under conditions whereby the interacted substances associate with the target DNA and cleave the target DNA molecule via transposase-mediated cleavage to provide a cleaved DNA product wherein the Mn +2 concentration is between about 1 mM and about 100 mM. a first DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for a transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase; a second DNA molecule comprising at least a portion that is double stranded, wherein the double stranded portion comprises a recognition sequence for the transposase and the DNA molecule further comprises a portion that does not comprise a recognition sequence for the transposase, wherein the non-recognition portion of the sequence is different from the non-recognition portion sequence of the first DNA molecule; and the transposase, wherein the transposase is a transposase from Vibrio harveyi and wherein combining the three substances allows them to interact; and