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).
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.
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).
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