Polymerase chain reaction is used for ?

Ans. is 'b' i.e., Amplification of DNA in vitroPCR is a method of enzymatic amplification of a target sequence of DNA.It is sensitive, selective (specific) and extremely rapid means of amplifying any desired sequence of double stranded DNA, which can be as sho as 50-100 base pairs (bp) and as long as 10 kbp.In PCR, the DNA to be amplified is replicated by DNA polymerase of Thermus aquaticus (Taq).Taq polymerase is used because it is thermostable, not denatured at a temperature upto 95degC (in PCR DNA is to be heated to 94deg-95deg C for separation of strands).For amplifying a desired DNA sequence in DNA, we have to know sho flanking sequences on either side of the target sequence so that complementary primers can be prepared.Primers are the synthetic oligonucleotides of 20-35 sequence, which have sequence complementary to flanking sequence, i.e. sequence of flanking region of target DNA sequence.Primers are amplified to produce desired sequence of DNA.