The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals
A plot of site-specific ω against amino acid positions for various advanced snake and cone snail venom-encoding genes is presented. Significantly detected positively selected sites (model 8; Bayes Empirical Bayes approach) are presented as large red circles. The red horizontal line represents the line of neutrality: points above and below this line indicate positive and negative selection, respectively. A corresponding bar plot is provided, which shows the computed ω value for the respective toxin class. Bar-plot color code: Panel A 1) β-defensins; 2) Cytotoxins; 3) PII-Disintegrins; 4) Group I PLA2s; 5) Group II PLA2s; 6) Kallikreins; 7) Psammophis SVMPs; 8) Advanced snake SVMPs; 9) Serine Proteases; 10) Lectins; 11) κ-3FTxs; 12) Type III α-neurotoxins; 13) Type II α-neurotoxins; Type I α-neurotoxins; and 14) CRISPs. Panel B Conus marmoreus—> 1) Superfamily M; 2) Superfamily I2; 3) Superfamily T; 4) Superfamily O2; C. geographus—> 5) Superfamily O1; 6) Superfamily O2; 7) Superfamily O1; 8) Superfamily M; 9) Superfamily A; 10) Conkunitzin; 11) Conantokin; 12) Con-ikot-ikot.