The attP-flanked w+ marker present in atow has been replaced (using phiC31:int-mediated recombination) with sequence that comprises wild-type ato sequence flanked by FRT3 recombinase target sites followed by the GAL4 coding region. The inserted sequence (FRT3 cassette plus GAL4 sequence) is flanked by inverted attR sites generated during the recombination event. The GAL4 coding region is not expressed in this allele.
atoFAFG4 homozygotes show wild-type phenotypes.