A cDNA fragment containing mutated H sequence has been reintroduced into the attP site present in TI{TI}HattP, resulting in a H locus carrying the amino acid replacement F237A. A residual attR site is present in the 5'UTR and a single loxP site is present in the 3'UTR.
HFA has visible | dominant | adult stage phenotype, suppressible by Su(H)[+]/Su(H)attP
HFA has mechanosensory chaeta | adult stage phenotype, suppressible by Su(H)[+]/Su(H)attP