Methods and compositions using populations of randomized modified FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. The recombinogenic modified FRT recombination sites can be employed in a variety of methods for targeted recombination of polynucleotides of interest, including methods to recombine polynucleotides, assess promoter activity, directly select transformed organisms, minimize or eliminate expression resulting from random integration into the genome of an organism, such as a plant, remove polynucleotides of interest, combine multiple transfer cassettes, invert or excise a polynucleotide, and identify and/or characterize transcriptional regulating regions are also provided.