An Hsp83 promoter drives expression of rec containing the amino acid replacement F29L (this replacement does not appear to affect the function of the rec protein produced). The protein also contains the amino acid replacements Y118H and V422A relative to the genome sequenced strain (these substitutions are present in CantonS flies).
recHsp83.PM rescues the the X chromosome nondisjunction and recombination defects which are seen in homozygous rec1 females.