Fig. 5

Hybrid snakes have protein expression profiles distinct from those of the parental species. a The non-metric multidimensional scaling (NMDS) analysis of protein composition and abundance showed that protein levels in the hybrid venom proteomes showed intermediate along the primary MDS axis. This analysis shows that the parental species and the hybrids have consistent protein expression levels. b Normalized counts of peptides detected by mass spectrometry for homologous proteins in the hybrids, compared to parental values, with y = x line plotted for reference. Although most of the hybrid data points lie outside the parental means (12 of 14, 1-sample proportions test, p = 0.00011), suggesting either under- or overdominance, common in hybrids, the overall the slope and the intercept of the best fit are not different from y = x (p = 0.36). Both analyses show that the hybrid proteomes are on average intermediate relative to those of P. elegans and P. flavoviridis, suggesting strong genetic effects on both their compositions and component levels