One of our two approaches for the shuffling of virus capsid genes, homology based capsid shuffling, makes use of conserved regions that flank the AAV capsid gene of all AAV serotypes. In this method, capsid genes are digested by DNaseI and amplified in a self-priming PCR reaction, thus creating a library of diverse, purely synthetic novel virus capsids. From this library, viruses of specific properties can be selected using targeted evolution. It has been shown that for example viruses isolated after selection on a breast cancer cell line (MDA-MB231) are able to more efficiently transducer breast cancer cells than other AAV2-based virus hybrids (Koerber et al., 2008).