Co-option of the same ancestral gene family gave rise to mammalian and reptilian toxins

• DOI: 10.1186/s12915-021-01191-1
• Publication Date: 2021-12-23T22:39:07Z
• Authors: Agneesh Barua; Ivan Koludarov; Alexander S. Mikh...
• Keywords: Concerted evolution; Exaptation

Abstract Background Evolution can occur with surprising predictability when organisms face similar ecological challenges. For most traits, it is difficult to ascertain whether this occurs due constraints imposed by the number of possible phenotypic solutions or because parallel responses shared genetic and regulatory architecture. Exceptionally, oral venoms are a tractable model trait evolution, being largely composed proteinaceous toxins that have evolved in many tetrapods, ranging from reptiles mammals. Given diversity venomous lineages, they believed convergently, even though biochemically all taxa. Results Here, we investigate ancestral genes harbouring biochemical activity may primed venom focusing on origins kallikrein-like serine proteases form core vertebrate venoms. Using syntenic relationships between flanking known toxins, traced origin kallikreins single locus containing one more nearby paralogous clusters. Additionally, phylogenetic analysis revealed mammals genetically distinct non-toxin ones. Conclusions machinery, these findings suggest tetrapod co-option proteins were likely already present saliva. We term such ‘toxipotent’—in case salivary had potent vasodilatory was weaponized lineages. Furthermore, ubiquitous distribution across vertebrates suggests evolution envenomation be common than previously recognized, blurring line non-venomous animals.