biotechnology.

DNA cloning is now days taking all over the research world in its magic. this is done by polymerases chain reaction, in which there are 3 steps: first : denaturing: the DNA is melted at 94 C for 1minute then : second: annealing: the primers are attached to DNA single strand at 3' end and wherever polymerase finds the bond between the primer and DNA is withstanding for long enough time then it got attached o that portion this is done at 54 C and 45 seconds: third: extension: this is done at 72 C for 2minutes: in which the polymerase go on attaching the nucleotides in solution to the single DNA strand till 5' end. 

so by this process from 1 DNA 2 are produced and from 2 DNA 4, 4 to 8 and so no exponentially after 36 cycles it about 60 billion DNA , this process also can be used for RNA trancription.

and also reverse transcription can be done..  this can be used for detection of disease...