The present invention relates to an Adeno-associated virus (AAV) library comprising a multitude of Adeno-associated virus (AAV) variants, wherein the viral particles of each AAV variant comprise a specific combination of (i) a strain-specific capsid polypeptide and (ii) a peptide inserted into said capsid polypeptide, and wherein said strain-specific capsid polypeptides are derived from at least two different AAV strains. The present invention further relates to a method for identifying an AAV variant infecting a target cell of interest comprising a)providing a library of AAV variants comprising each AAV variant in an isolated manner, wherein each AAV variant of said library of AAV variants comprises a specific combination of (i) a strain-specific capsid polypeptide and (ii) a peptide inserted into said capsid polypeptide and wherein said strain-specific capsid polypeptides are derived from at least two different AAV strains； b)contacting each of said AAV variants individually with said target cell of interest； c) determining AAV infection of said target cells of interest； and d) based on the result of step c), identifying a variant AAV infecting a target cell of interest； and to a library of polynucleotides,a library of cloning cells, and to uses related thereto.La présente invention concerne une bibliothèque de virus adéno-associés (AAV) comprenant une multitude de variants de virus adéno-associés (AAV), les particules virales de chaque variant d'AAV comprenant une combinaison spécifique (i) d'un polypeptide de capside spécifique de souche et (ii) d'un peptide inséré dans ledit polypeptide de capside, et lesdits polypeptides de capside spécifiques de souche étant dérivés d'au moins deux souches différentes d'AAV. La présente invention concerne en outre un procédé permettant d'identifier un variant d'AAV infectant une cellule cible d'intérêt, consistant : a) à fournir une bibliothèque de variants d'AAV comprenant isolément chaque variant d'AAV, chaque variant d'AAV
