#"cDNA or complementary DNA"# has nucleotide sequence complementary to the processed #"mRNA# from which it has been synthesized in a process called reverse transcription that is catalyzed by enzyme i.e reverse transcriptase.
#cDNA# being synthesized from single stranded #"mRNA"# is firstly synthesized as a single stranded molecule. And it remains single stranded until #"PCR(polymerase chain reaction)"# is carried out. In PCR that is aided by #"DNA polymerase"# (e.g Taq DNA polymerase) , it gets it's double stranded form.
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