Figure 1.

Terminology and amino acid distances. (ai) Peptide copy terminology exemplified by three aligned ASTa prepropeptides from species a1-3. (aii) Processing at dibasic processing sites (indicated in red in (ai)) yields the four neuropeptides ASTa1-4. The C-terminal glycine is further processed to yield the C-terminal amidation. Peptide copies aligning at the same position in the precursor (for example, ASTa1 of species a1-3) will be referred to as orthocopies, which do not have to be sequence-identical. The different copies in a precursor of a single species are paracopies (for example, ASTa1-4 of species a1) = not at the same location. Paracopies may or may not be sequence-identical. (b) Different types of amino acid distances obtained by pairwise comparisons. (bi) The average distance D_o between orthocopies is the arithmetic mean of all individual pairwise distances. It does not contain distances between different paracopies. (bii) The average distance between all peptides within a family D_f is the arithmetic mean of all individual pairwise distances. It contains all pairwise distances between orthocopies and all paracopies. (biii) The net distance D_np between paracopies is similar to D_f after subtraction of D_o. It does not contain the pairwise distances between each set of orthocopies.