The genomic DNA fragment located between the P-elements in the insertion present in y+s has been inverted.
wild-type
y+s11 has phenotype, non-enhanceable by su(Hw)2
y+s11 has phenotype, non-enhanceable by mod(mdg4)ul
y+s11 has phenotype, non-suppressible by su(Hw)2
y+s11 has phenotype, non-suppressible by mod(mdg4)ul