Kartik Sunagar

Marie Curie Fellow

www.toxickartik.com

The fascinating world of animal venoms

Research Highlights

Hi! I am an evolutionary biologist with a passion for research on animal venoms. My research attempts to unravel the forces of natural selection that sculpt toxin molecular scaffolds in the animal kingdom. As part of my PhD research (thesis titled "The Molecular Evolution of Animal Venom"), I studied various aspects of venoms in a diversity of animal lineages: centipedes, scorpions, spiders, cone snails, coleoids (octopus, cuttlefish and squid), vampire bats, snakes and lizards. Currently, in addition to working on various aspects of venom evolution (evolutionary arms races, evolution of venom resistance, etc.), I am pursuing research (funded by Marie Curie fellowship) to understand the evolutionary development of cells that secrete venoms. Venom is defined as ‘a secretion, produced in a specialized gland in one animal and delivered to a target animal through the infliction of a wound (regardless of how tiny it may be), which contains molecules that disrupt normal physiological or biochemical processes in the victim so as to facilitate feeding or defense by the producing animal’ (Fry et al. 2009; Fry et al. 2013). This definition encompasses creatures normally considered venomous (e.g., scorpions, snakes, spiders, centipedes) as well as animals that have not been traditionally recognized as such (e.g., leeches, ticks, vampire bats, coleoids). Acknowledgment of the evolutionary analogy of the recruitment and use of toxins in all these animals increases the number of known independent occasions in which venom has evolved independently. In addition, this acknowledgment improves our understanding of the factors underlying the evolution of venoms and their associated proteins while also drawing attention to the vast pool of unstudied toxins (Fry et al. 2009). Venom has been a key innovation in the evolutionary history of an incredibly diverse range of animals. Even using the traditional definition of venom, venom systems are believed to have evolved independently on at least twenty occasions in extant lineage. If lineages such as ticks, leeches, vampire bats etc. are rightfully recognized as venomous, the number of independent evolutionary events in which venom has originated increases to over thirty. Intriguing fossil evidence has also led to speculation about the possibility of extinct venomous lineages represented by the theropod dinosaur Sinornithosaurus (Gong et al. 2010), a genus of feathered dromaeosaurid dinosaur, and the extinct pantolestid mammal Bisonalveus browni (Gong et al. 2010). Euchambersia, a genus from the family Therocephalia (ancestral mammalian lineage), are known to have had venom glands attached to their canine teeth. Hence, they have been theorized to have used venom for predation in the Late Permian epoch 250 million years ago. The extant venomous organisms belong to a vast variety lineages, including arthropods (scorpions, spiders, centipedes, bees, wasps, caterpillars of certain moths - Lonomia), cnidarians (jellyfish, anemone), molluscs (cone snails, squid, cuttlefish, octopus), fishes (sharks, stingrays, chimaeras, teleost fishes like catfish, stonefish, scorpionfish, lionfish, surgeonfish, rabbitfish, onejaws, etc.), amphibians (certain species of salamanders with sharp ribs for injecting venom), mammals (vampire bats, certain species of shrews, male platypus, slender loris), snakes (cobras, kraits, vipers, the so called ‘non-venomous’ snakes) and lizards (monitor lizards, helodermatid lizards).