Amino acid replacement: G545R.
Nucleotide substitution: G1633C.
Adults carrying fz76B1.Act5C in a fz21 background have an average of 2.6 +/- 0.9 extra tarsal joints in the leg compared to wild type.
fz76B1.Act5C shows poor rescue of the wing margin phenotype of fz21 fz2C1 double homozygous clones.