Modification of adeno-associated virus (AAV) cap gene by DNA shuffling. The cap genes of eight AAV serotypes were amplified and mixed together in the same ratio. They were then fragmented by transient DNase I treatment. The small DNA fragments were reassembled by primerless PCR and homologous recombination were introduced in this step. Lastly, the full-length cap genes were amplified and inserted into the plasmid vector with AAV2 rep gene and ITR sequences for generation of plasmid and virus libraries.