Figure 1.

Amino acid diversity in conopeptides. The position-specific diversity of amino acid for each conopeptide regions (ER signal in red, pro- in green, and mature region in purple) belonging to the 4 largest gene superfamilies A, M, O1 and T (the remaining superfamilies are presented in Additional file 1: Figure S1). The true diversity of order 2 (or inverse Simpson index, 1/λ) have been calculated according to the following equation in order to take into account the amino acid richness R, their average proportional abundance p_i, as well as the variability of sequence lengths for each regions: $1/\mathit{\lambda }=1/\sum _{\mathit{i}=1}^{\mathit{R}}{\mathit{p}}_{\mathit{i}}^2$. For each amino acid position, a color gradient applies to the diversity index (from 0 in light to higher values in darker color).