Data from: Convergent adaptation to dangerous prey proceeds through the same first-step mutation in the garter snake Thamnophis sirtalis
Hague, Michael Thomas Jonathan, University of Virginia
Feldman, Chris R., University of Nevada Reno
Brodie Jr., Edmund D., University of Virginia
Brodie III., Edmund D., University of Virginia
Hague, Michael T.J., University of Virginia
Brodie, Edmund D., University of Virginia, Utah State University
Published Mar 27, 2017 on Dryad.
Cite this dataset
Hague, Michael Thomas Jonathan et al. (2017). Data from: Convergent adaptation to dangerous prey proceeds through the same first-step mutation in the garter snake Thamnophis sirtalis [Dataset]. Dryad. https://doi.org/10.5061/dryad.3k15h
Convergent phenotypes often result from similar underlying genetics, but recent work suggests convergence may also occur in the historical order of substitutions en route to an adaptive outcome. We characterized convergence in the mutational steps to two independent outcomes of tetrodotoxin (TTX) resistance in separate geographic lineages of the common garter snake (Thamnophis sirtalis) that coevolved with toxic newts. Resistance is largely conferred by amino acid changes in the skeletal muscle sodium channel (NaV1.4) that interfere with TTX-binding. We sampled variation in NaV1.4 throughout western North America and found clear evidence that TTX-resistant changes in both lineages began with the same isoleucine-valine mutation (I1561V) within the outer pore of NaV1.4. Other point mutations in the pore, shown to confer much greater resistance, accumulate later in the evolutionary progression and always occur together with the initial I1561V change. A gene tree of NaV1.4 suggests the I1561V mutations in each lineage are not identical-by-decent, but rather they arose independently. Convergence in the evolution of channel resistance is likely the result of shared biases in the two lineages of Th. sirtalis – only a few mutational routes can confer TTX resistance while maintaining the conserved function of voltage-gated sodium channels.
Bayesian consensus tree
.tre file from the partitioned Bayesian analysis in MrBayes.
Maximum likelihood consensus tree
.tre file from the partitioned maximum likelihood analysis in RAxML.
Phenotypic TTX resistance data
Physiological TTX resistance data of populations assayed for the first time in this study.