The king cobra genome reveals dynamic gene evolution and adaptation in the snake venom system

作者：Freek J. Vonk, Nicholas R. Casewell, Christiaan V. Henkel, Alysha M. Heimberg, Hans J. Jansen, Ryan J.R. McCleary, Harald M. E. Kerkkamp, Rutger Vos, Isabel Guerreiro, Juan J. Calvete, Wolfgang Wüster, Anthony E. Woods, Jessica M. Logan, Robert A. Harrison, Todd A. Castoe, A. P. Jason de Koning, David D. Pollock, Mark Yandell, Diego Calderon, Camila Renjifo, Rachel B. Currier, David Salgado, Davinia Plá, Líbia Sanz, Asad S. Hyder, José M. C. Ribeiro, Jan W. Arntzen, Guido E.E.J.M. van den Thillart, Marten Boetzer, Walter Pirovano, Ron P. Dirks, Herman P. Spaink, Denis Duboule, Edwina McGlinn, R. Manjunatha Kini, Michael K. Richardson · 发表于：Proceedings of the National Academy of Sciences · 年份：2013 · DOI：10.1073/pnas.1314702110 · 被引用次数：498 · 研究领域：Venomous Animal Envenomation and Studies、Amphibian and Reptile Biology、Cellular transport and secretion

Snakes are limbless predators, and many species use venom to help overpower relatively large, agile prey. Snake venoms are complex protein mixtures encoded by several multilocus gene families that function synergistically to cause incapacitation. To examine venom evolution, we sequenced and interrogated the genome of a venomous snake, the king cobra (Ophiophagus hannah), and compared it, together with our unique transcriptome, microRNA, and proteome datasets from this species, with data from other vertebrates. In contrast to the platypus, the only other venomous vertebrate with a sequenced genome, we find that snake toxin genes evolve through several distinct co-option mechanisms and exhibit surprisingly variable levels of gene duplication and directional selection that correlate with their functional importance in prey capture. The enigmatic accessory venom gland shows a very different pattern of toxin gene expression from the main venom gland and seems to have recruited toxin-like lectin genes repeatedly for new nontoxic functions. In addition, tissue-specific microRNA analyses suggested the co-option of core genetic regulatory components of the venom secretory system from a pancreatic origin. Although the king cobra is limbless, we recovered coding sequences for all Hox genes involved in amniote limb development, with the exception of Hoxd12. Our results provide a unique view of the origin and evolution of snake venom and reveal multiple genome-level adaptive responses to ...