Amino acid replacement: R274H.
Nucleotide substitution: G821A.
Adults carrying fz39B2.Act5C in a fz21 background have an average of 1.1 +/- 0.3 extra tarsal joints in the leg compared to wild type.
fz39B2.Act5C rescues the wing margin phenotype of fz21 fz2C1 double homozygous clones.