Prior art teaches an effective packaging capacity for adeno-associated virus and adeno-associated viral vectors of 4.1 kb to 4.9 kb as well as a packaging limit of 5.2 kb to 5.6 kb. However, the inventor discovered that this packaging limit as well as that effective packaging capacity does not apply to all AAV serotypes: Whereas it is true that efficient packaging of AAV serotype 2 is limited to less than 5 kb, the inventor discovered that one can efficiently package more than 6 kb of genetic information into AAV capsids of other AAV serotypes, particularly into capsids of AAV serotype 5 and--to a lesser extent--into capsids of AAV serotype 7. This discovery will be useful in the context of gene therapy where large transgenes will have to be transferred such as the ABCA4 coding sequence, the Factor VIII coding sequence, the B-deleted Factor VIII coding sequence or minidystrophin genes.