The present invention is directed generally to methods facilitating the cloning of nucleic acid molecules. In particular, the invention relates to the use of polymerase inhibitors, including but not limited to anti-polymerase antibodies (such as anti-Taq antibodies) and fragments thereof, to inactivate residual polymerase activity remaining after the amplification (particularly via PCR) of a target nucleic acid molecule. The invention further provides compositions, particularly storage-stable compositions, comprising one or more components, such as one or more restriction endonucleases and one or more polymerase inhibitors, that are useful in cloning amplified or synthesized nucleic acid molecules by the above-described methods. The invention also relates to nucleic acid molecules produced by these methods, and to genetic constructs (such as vectors) and host cells comprising these nucleic acid molecules.