Agneesh Barua, Many Options, Few Solutions: Over 60 Million Years Snakes Converged on a Few Optimal Venom Formulations

Speaker: Agneesh Barua, Ecology and Evolution Unit

Title: Many Options, Few Solutions: Over 60 Million Years Snakes Converged on a Few Optimal Venom Formulations

Abstract: Gene expression changes contribute to complex trait variations in both individuals and populations. However, the evolution of gene expression underlying complex traits over millions of years remains poorly understood. Being comprised of proteinaceous cocktails, snake venoms are unique in that the expression of each toxin can be quantified and mapped to a distinct genomic locus and traced for tens of millions of years. This characteristic of snake venom allows researches to ask specific questions related to evolutionary biology and genetics. In my talk, I will show how we used snake venom and principles from quantitative genetics to understand how complex traits evolve through millions of years. One of the major results was that the genes comprising venom are free to evolve. Meaning, snake venom can be made up of any combination of toxins. However, while many combinations are in principle possible, in nature, snakes tend to use envenomation strategies focussed around only a few toxins. The most important ones being: metalloproteases, three-finger toxins, serine proteases, and phospholipases A2. While most modern snakes prioritize either a single or a combination of major toxin families they are repeatedly recruited and lost. We show that over long timescales the venom trait was shaped by ecological filtering, that permits a small number of optimal solutions. This lead to many snakes developing similar kinds of venom. This study opens up further questions about similar genetic mechanisms that might have lead to the diversification of other characters across the animal kingdom.

After the seminar there will be a discussion with free pizza and drinks!