Amino acid replacement: C107Y.
Nucleotide substitution: G320A.
Adults carrying fz26C1.Act5C in a fz21 background have an average of 2.9 +/- 0.3 extra tarsal joints in the leg compared to wild type.
fz26C1.Act5C shows poor rescue of the wing margin phenotype of fz21 fz2C1 double homozygous clones.