Patent ID: 6939712

Claim:
A method for muting expression of a target gene in a population of animal cells in vitro, the method comprising: (a) screening to identify a muting nucleic acid composition having a sequence that is homologous to a sequence in the target gene, the nucleic acid composition being double stranded, wherein screening to identify comprises the steps of: (i) synthesizing a plurality of nucleic acid composition homologous to all or part of the target gene and introducing said plurality of nucleic acid composition into a cultured population of animal cells; (ii) selecting a nucleic acid composition that inhibits expression of the target gene in said cultured population of animal cells, thereby identifying said muting nucleic acid composition; (b) delivering the muting nucleic acid composition into a population of animal cells in vitro; and (c) muting expression of the target gene in said animal cells, wherein said muting nucleic acid composition inhibits expression of the target gene.