Electronic versions



  • Giulia Zancolli
  • Juan J. Calvete
    Instituto de Biomedicina de Valencia
  • Michael D. Cardwell
    San Diego State University
  • Harry W. Greene
    Cornell University
  • William K. Hayes
    Loma Linda University
  • Matthew J. Hegarty
    Aberystwyth University
  • Hans-Werner Herrmann
    University of Arizona, Tucson
  • Andrew T. Holycross
    Arizona State University
  • Dominic I. Lannutti
    University of Texas at El Paso
  • John F. Mulley
  • Libia Sanz
    Instituto de Biomedicina de Valencia
  • Zachary D. Travis
    Loma Linda University
  • Joshua R. Whorley
    Seattle Central College
  • Catharine E. Wuster
  • Wolfgang Wuster
Understanding the origin and maintenance of phenotypic variation, particularly across a continuous spatial distribution, represents a key challenge in evolutionary biology. For this, animal venoms represent ideal study systems: they are complex, variable, yet easily quantifiable molecular phenotypes with a clear function. Rattlesnakes display tremendous variation in their venom composition, mostly through strongly dichotomous venom strategies, which may even coexist within a single species. Here, through dense, widespread population-level sampling of the Mojave rattlesnake, Crotalus scutulatus, we show that genomic structural variation at multiple loci underlies extreme geographical variation in venom composition, which is maintained despite extensive gene flow. Unexpectedly, neither diet composition nor neutral population structure explain venom variation. Instead, venom divergence is strongly correlated with environmental conditions. Individual toxin genes correlate with distinct environmental factors, suggesting that different selective pressures can act on individual loci independently of their co-expression patterns or genomic proximity. Our results challenge common assumptions about diet composition as the key selective driver of snake venom evolution and emphasize how the interplay between genomic architecture and local-scale spatial heterogeneity in selective pressures may facilitate the retention of adaptive functional polymorphisms across a continuous space.


  • Animals, Arizona, Biological Evolution, California, Crotalid Venoms/genetics, Crotalus/genetics, Diet, Environment, Gene-Environment Interaction, Genotype, Phenotype, Population Dynamics
Original languageEnglish
Pages (from-to)20182735
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1898
Early online date13 Mar 2019
Publication statusPublished - 13 Mar 2019

Total downloads

No data available
View graph of relations