Amino acid replacement: E373K.
Nucleotide substitution: G1117A.
Adults carrying fz4C3.Act5C in a fz21 background have an average of 1.0 +/- 0.0 extra tarsal joints in the leg compared to wild type.
fz4C3.Act5C rescues the wing margin phenotype of fz21 fz2C1 double homozygous clones.