Snake venom evolution

Snake venom evolution 

It has long been thought that snake venom evolves via the duplication of genes with a role elsewhere in the body followed by recruitment into the venom gland. However, there are a number of gaps in this thesis, including the mechanism(s) of repeated gene duplication and the process(es) by which the duplicated genes are recruited into a novel tissue. We’re currently using next-generation sequencing approaches (including quantitative comparative transcriptomics and whole genome sequencing) to investigate these and other processes in the evolution of variation in snake venom composition, using a mixture of venomous species (inlcuding saw-scaled vipers (Echis coloratus and Echis pyramidum), puff adders (Bitis arietans) and monocled cobras (Naja kaouthia) among others) and non-venomous species (corn snakes, house snakes, royal pythons and leopard geckos).

 

Echis coloratus Echis carinatus

Venomous snake genomics

We’re now working with Dovetail Genomics to generate a high-quality genome sequence assembly for the painted saw-scaled viper (Echis coloratus), which we hope will answer some of the still-unsolved questions regarding snake venom evolution.

dovetail

I’m also co-investigator on a Leverhulme Trust-funded project looking at the genetic basis of venom variation in the Mojave rattlesnake, Crotalus scutulatus (with Wolfgang Wüster, Principal Investigator).

Relevant publications:

Hargreaves AD and Mulley JF (2015) ‘Assessing the utility of the Oxford Nanopore MinION for snake venom gland cDNA sequencing’ PeerJ 3:e1441; DOI 10.7717/peerj.1441

Hargreaves, AD, Tucker, A, Mulley JF (2015) ‘A Critique of the Toxicoferan Hypothesis’ Evolution of Venomous Animals and Their Toxins (Part of the series Toxinology, Eds: P. Gopalakrishnakone, Anita Malhotra) ISBN: 978-94-007-6727-0 (Online) pp 1-15

Hargreaves AD, Swain MT, Logan DW and Mulley JF. ‘Testing the Toxicofera: comparative reptile transcriptomics casts doubt on the single, early evolution of the reptile venom system’ Toxicon 92: 140-156

Hargreaves AD & Mulley JF (2014) ‘A plea for standardized nomenclature of snake venom toxins’ Toxicon 90: 351-353

Hargreaves AD, Swain MT, Hegarty MJ, Logan DW and Mulley JF (2014) ‘Restriction and recruitment – gene duplication and the origin and evolution of snake venom toxins’ Genome Biology and Evolution 6(8): 2088-2095