Knockout Strategy Guide

Check the IMPC (International Mouse Phenotyping Consortium) database and published literature. If homozygous null mutations cause embryonic lethality in previous studies, a conditional approach is required. If no data exists, we recommend designing a conditional (floxed) allele that can function as a conventional knockout when crossed to germline Cre, while preserving conditional options.

Choose conventional knockout if the gene is not essential for development, you want global deletion, and you don't need tissue specific control. Choose conditional knockout if the gene causes embryonic lethality, you need tissue specific deletion, or you anticipate studying gene function in multiple tissues.

If the knockout was generated using a knockout-first allele design, yes. Flp recombinase converts it to a conditional-ready allele. If the knockout was generated by simple exon deletion without the cassette system, a new conditional targeting project would be required.