What is Gene targeting?
[[Image:ChimericMouseWithPups.jpg| thumb | A [[mosaic (genetics)|chimeric]] mouse with its offspring. The parent mouse had its Agouti gene (for banded coat colour) targeted.]] '''Gene targeting''' is a [[genetic]] technique for replacing an existing [[gene]] with a mutated (changed) one. It can be done in lab [[mice]] or some other [[model organism]]. The method can be used to delete a gene, remove control sections, add a gene, and introduce point mutations. Gene targeting can be permanent or conditional. Conditions, for example, can be a specific time during development in the life of the organism or limited to a specific tissue. To date, this method has been applied to a number of species including ''[[Drosophila melanogaster]]'', [[tobacco]],<ref name=Cai>Cai C.Q. et al. 2008. Targeted transgene integration in plant cells using designed zinc finger nucleases. ''Plant Molecular Biology'' '''69''' (6): 699. doi:10.1007/s11103-008-9449-7. PMID 19112554</ref><ref name=Townsend2009> Townsend J.A. ''et al.'' 2009. High-frequency modification of plant genes using engineered zinc-finger nucleases. ''Nature'' '''459''' (7245): 442. doi:10.1038/nature07845. PMID 19404258</ref> [[maize|corn]],<ref name=Shukla2009>Shukla V.K. et al. 2009. Precise genome modification in the crop species ''Zea mays'' using zinc-finger nucleases. ''Nature'' '''459''' (7245): 437. doi:10.1038/nature07992. PMID 19404259</ref> [[human]] cells.<ref name=Urnov2005>Urnov F.D. et al. 2005. Highly efficient endogenous human gene correction using designed zinc-finger nucleases. ''Nature'' '''435''' (7042): 646. doi:10.1038/nature03556. PMID 15806097</ref> [[mouse|mice]],<ref name=Cui2010>Cui X. 2010. Targeted integration in rat and mouse embryos with zinc-finger nucleases. ''Nature Biotechnology'' '''29''' (1): 64. doi:10.1038/nbt.1731. PMID 21151125</ref> and [[rat]]s.<ref name=Cui2010/> == 2007 Nobel prize== [[Mario Capecchi|Mario R. Capecchi]], [[Martin Evans|Martin J. Evans]] and [[Oliver Smithies]] were awarded the 2007 [[Nobel Prize in P