FLP recombinase and FRT target sites comprise the most widely used site-specific recombination system in Drosophila. See alternative site-specific recombination systems for other options such as cre–lox.

Variant FLP proteins with different activity levels have been isolated. See defined FLP variants for stocks with known FLP sequences. As described in more detail there, most fly constructs appear to express one of two FLP variants. We do not know the FLP allele present in most Bloomington stocks.

The following table shows the most generally useful FLP stocks. Use the Search option to find all available stocks with a particular insertion.

There is some uncertainty in the identification of X chromosome hs-FLP insertions in many stocks. See note for more information.