Amplification-based cloning method

A method of isolating a nucleic acid molecule of interest from a mixture of nucleic acid molecules, comprising:

• (i) providing a recombinant nucleic acid library comprising a heterogeneous population of circular template nucleic acid molecules modified such that they are selectively digestible by an enzyme;
• (ii) contacting the library with a first primer and a second primer, said primers capable of annealing to complementary strands of a nucleic acid molecule of interest present in the library to produce an annealed mixture, and wherein
• the two primers extend in opposite directions relative to each other during primer extension;
• and
• the 5′ ends of the two primers are adjacent to each other;
• (iii) subjecting the annealed mixture to conditions under which primer extension occurs, thereby producing a reaction mixture containing linear primer extension products;
• (iv) digesting the mixture containing linear primer extension products with the enzyme of (i), wherein said enzyme selectively digests template nucleic acid molecules but not the primer extension products, resulting in a population enriched for the nucleic acid molecule of interest.