Figure 7. Sequences and evolution of the superfamily of Tarantulas KTTs.

(A) The distribution of the Ornithoctonus huwena and Ornithoctonus hainana. The red and blue triangles indicate the regions in which these spiders are found. (B) A minimum evolution (ME) tree of spider KTTs with sequence alignment. The sub-Kunitz toxin family and native KTT family are marked by orange and light blue backgrounds. The colored diamonds indicate the possible key events of the evolution of spider KTTs: brown, the loss of two amino acids after the recruitment event occurred; red, the substitution of the fourth highly conserved cysteine by a Tyrosine; green, a series of sequence divergences; yellow, a duplication event in Ornithoctonus huwena; blue, the loss of the orphan cysteine residue. The key residues mutated in the key events are marked by backgrounds with the corresponding color.