Animal Venoms: Origin, Diversity and Evolution

Abstract

Venomous 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 Concepts Venom 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.

Buzz Kill: Function and Proteomic Composition of Venom from the Giant Assassin Fly Dolopus genitalis (Diptera: Asilidae)

“…Studies on the venom systems of arachnids, snakes, and marine cone snails, among others, have revealed that venoms are typically complex composites of peptides, small molecules, pore-forming proteins, and enzymes that target the nervous and/or cardiovascular system to incapacitate prey or deter predators. Venom has evolved multiple times among animals [ 1 , 2 , 3 ], and the scope of venomous animal groups whose venom biochemistry has been examined is ever-expanding, having recently grown to encompass such animals as the platypus [ 4 ], centipedes [ 5 ], assassin bugs [ 6 , 7 ], and polychaete worms [ 8 ].…”

Identification of Novel Toxin Genes from the Stinging Nettle Caterpillar Parasa lepida (Cramer, 1799): Insights into the Evolution of Lepidoptera Toxins

“…Many lepidopteran species from different families can produce venoms, suggesting that toxin genes evolved independently many times in Lepidoptera evolution. Convergent evolution is a fundamental process in animal venom evolution [ 3 , 113 ]. Our findings indicate that some toxin classes have been repeatedly recruited into the venom of Lepidoptera, particularly serine protease, protease inhibitor, phospholipase A2, and lectin, as reported in P .…”

Biochemical and Proteomic Characterization, and Pharmacological Insights of Indian Red Scorpion Venom Toxins

“…Animal venoms are complex secretions consisting mainly of bioactive proteins and peptides ( Fry et al, 2009 ; Casewell et al, 2013 ) that primarily serve as a chemical means of protection and subduing prey. Venom has evolved independently throughout the animal kingdom ( Casewell et al, 2013 ; Suranse et al, 2018 ); consequently, it is present in all major animal lineages ( Holford et al, 2018 ). All of the 1,500 extant scorpion species are venomous.…”