Animal Venoms: Origin, Diversity and Evolution

AbstractVenomous animals and their venoms have intrigued mankind for millennia. Venoms are complex cocktails of chemically diverse components that disrupt the physiological functioning of the victim to aid the venom‐producing animal in defence and/or feeding. Despite evolving independently on at least 30 occasions in the animal kingdom, venom exhibits remarkable evolutionary convergence, both in composition and biochemical activity. Various factors, including geography, diet, predator pressure, evolutionary arms race and phylogenetic history, underpin the diversification of venoms. Certain venomous animals, particularly snakes, are medically important and are responsible for tens of thousands of permanent loss‐of‐function injuries and deaths in humans every year. At the same time, as venom harbours many bioactive and highly specific components, it has tremendous potential applications in the development of novel lifesaving therapeutics and environment‐friendly agrochemicals. Several wonder drugs based on venom proteins have saved millions of lives worldwide, and many others are in development.Key ConceptsVenom has evolved independently ∼30 times in the animal kingdom to assist the venom‐producing animal in self‐defence and/or prey capture.A remarkable convergence can be observed in the composition and bioactivity of venoms.While most animals modified their salivary glands into venom glands, the duck‐billed platypus and echidna evolved venom glands through the evolutionary tinkering of sweat glands.Cnidarians evolved peculiar cell types to inject venom into their victims, while many hymenopterans have modified their ovipositors for venom injection.The strong influence of positive Darwinian selection has driven the evolutionary diversification of venoms, while the structural integrity is conserved by purifying selection.