Composition and evolution of venom in snakes from the tribe Hydropsini

Abstract

The family Dipsadidae presents a great diversity of snakes, many of which have some kind of venom. However, the venom from that family is still far less studied than that of other snake groups involved with human accidents. The present project aims to systematically study the venom of the Hydropsini tribe, composed of aquatic Dipsadidae. The tribe, divided into 3 genera, being Helicops the most diverse and widespread, contains snakes with a highly piscivorous diet, although some may be slightly more generalist. From the description of venom proteome (sequenced by mass spectrometry) and of the Durvenoy's gland (obtained through next-generation Illumina technology) the venom composition will be revealed. This way, it is not only expected that variants of previously known toxins are unraveled, but also new possible toxin groups may be described. For that, ToxCodan pipeline for annotation will be used. Also, through dN/dS and phylogenetic variance analysis, we expect to understand how natural selection has shaped the sequences and expression of toxin genes. At last, with the available data on the tribe diet, it will be possible to search for relationships between shifts in diet and venom composition. All these results will contribute to a more holistic understanding of the evolution of toxin coding genes in snakes, while also elucidating if the evolution of these genes is associated with the diversification of the group. (AU)