The present invention provides methods of amplifying a target nucleic acid utilizing duplex primer. The first strand of the primer comprises a random nucleotide sequence of about 6 to about 9 nucleotides in length that is able to hybridize to the target nucleic acid and a tag sequence. The second strand of the primer comprises a sequence complementary to the tag sequence allowing the primer to form a duplex and the ability to bind the tag sequence of the product nucleic acid for further amplification. The resulting nucleic acid produced contains tag sequences on both the 3′- and 5′-termini.