Amplification of mixed sequence nucleic acid fragments

A method of amplifying a mixture of different-sequence nucleic acid fragment strands, comprising

• manipulating the nucleic acid fragment strands to form a mixture of different sequence DNA fragment strands, where each DNA fragment strand has a 3'-end and further contains a 5'-end common sequence,
• treating the DNA fragment strands with terminal deoxynucleotide transferase and a selected triphosphate, to add a homopolymeric sequence to the 3' ends,
• mixing the DNA fragment strands containing the homopolymeric sequence with (i) a homopolymer primer that is complementary to said homopolymeric sequence, (ii) a common-sequence primer that has the same sequence as said common sequence, (iii) heat-stable DNA polymerase and (iv) all four deoxynucleotide triphosphates,
• heat denaturing the DNA fragment strands,
• annealing the mixture under conditions to form DNA fragment strand/primer duplexes,
• reacting the mixture under conditions in which the DNA fragment strand/primer duplexes are converted to double-stranded DNA molecules,
• repeating said denaturing, annealing, and reacting, until a desired degree of fragment amplification has been achieved.

A method of preparing a mixture of single-stranded RNA fragments for cloning in a cloning vector, comprising

• transcribing the RNA fragments to an RNA/DNA complex using an RNA-strand primer, where said RNA-strand primer (i) has a sequence complementary to a 3' sequence of the RNA fragments and (ii) is effective to produce in the resulting RNA/DNA duplex DNA fragment strands having a selected common 5'-end sequence,
• treating the DNA fragment strands with terminal deoxynucleotide transferase in the presence of a selected deoxynucleotide, to form a homopolymeric sequence at the 3'-end of the DNA fragment strands,
• mixing the DNA fragment strands containing the homopolymeric sequence with (i) a homopolymer primer having a binding sequence which is complementary to the 3'-end homopolymeric sequence of the DNA fragment strands, (ii) a common-sequence primer which has the same sequence as said selected common 5'-end sequence, (iii) a heat-stable DNA polymerase and (iv) all four deoxynucleotide triphosphates,
• heat denaturing the DNA fragment strands,
• annealing the mixture under conditions to form DNA fragment stand/primer duplexes,
• reacting the mixture under conditions in which the DNA fragment strand/primer duplexes are converted to double-stranded DNA molecules,
• repeating said denaturing, annealing, and reacting steps until a desired degree of fragment amplification has been achieved.