Amino acid replacement: I472K.
Nucleotide substitution: T1415A.
Adults carrying fz39D1.Act5C in a fz21 background have an average of 1.8 +/- 0.8 extra tarsal joints in the leg compared to wild type.
fz39D1.Act5C rescues the wing margin phenotype of fz21 fz2C1 double homozygous clones.