Hi! Raj U can cut DNA specifically using restriction endonucleases. For more details on this u can see: http://arbl.cvmbs.colostate.edu/hbooks/genetics/biotech/enzymes/ http://www.accessexcellence.org/AE/AEC/CC/restriction.html http://biowww.net/mynews/tree.php?group_name=bionet.molbio.methds-reagnts&begin=0