Evolutionary diversification of TTX-resistant sodium channels in a predator–prey interaction

  title={Evolutionary diversification of TTX-resistant sodium channels in a predator–prey interaction},
  author={Shana L. Geffeney and Esther Fujimoto and Edmund D. Brodie and Peter C. Ruben},
Understanding the molecular genetic basis of adaptations provides incomparable insight into the genetic mechanisms by which evolutionary diversification takes place. Whether the evolution of common traits in different lineages proceeds by similar or unique mutations, and the degree to which phenotypic evolution is controlled by changes in gene regulation as opposed to gene function, are fundamental questions in evolutionary biology that require such an understanding of genetic mechanisms. Here… 

Convergent Evolution of Tetrodotoxin-Resistant Sodium Channels in Predators and Prey.

Gene Conversion Facilitates the Adaptive Evolution of Self-Resistance in Highly Toxic Newts

This work reconstructs the origins of TTX self-resistance by sequencing the entire Nav gene family in newts and related salamanders and demonstrates that gene conversion can accelerate the coordinated evolution of gene families in response to a common selection pressure.

Predictably Convergent Evolution of Sodium Channels in the Arms Race between Predators and Prey

Trade-offs between the fundamental role of NaV1 proteins in selective permeability of Na+ and their ability to resist binding by TTX generate a highly constrained adaptive landscape at the level of the protein.

Predictably Convergent Evolution of Sodium Channels in the Arms Race between Predators and Prey.

Trade-offs between the fundamental role of NaV1 proteins in selective permeability of Na+ and their ability to resist binding by TTX generate a highly constrained adaptive landscape at the level of the protein.

Constraint shapes convergence in tetrodotoxin-resistant sodium channels of snakes

It is demonstrated that constraints resulting from functional tradeoffs between ion channel function and toxin resistance led to predictable patterns of evolutionary convergence at the molecular level, suggesting that natural selection may be frequently constrained to produce similar genetic outcomes even when operating on independent lineages.

Toxin-resistant sodium channels: parallel adaptive evolution across a complete gene family.

This study shows how 4 taxonomically diverse species of pufferfishes each evolved resistance to the guanidinium toxins tetrodotoxin and saxitoxin via parallel amino acid replacements across all 8 sodium channels present in teleost fish genomes.

Genetic architecture of a feeding adaptation: garter snake (Thamnophis) resistance to tetrodotoxin bearing prey

The simple genetic architecture of TTX resistance in garter snakes may significantly impact the dynamics of phenotypic coevolution, and the contribution of Nav1.4 alleles is evaluated to suggest that this locus is a major effect locus.

Parallel Evolution of Tetrodotoxin Resistance in Three Voltage-Gated Sodium Channel Genes in the Garter Snake Thamnophis sirtalis

The results demonstrate that the molecular basis of adaptation may be both repeatable across members of a gene family and predictable based on functional considerations.



Mechanisms of Adaptation in a Predator-Prey Arms Race: TTX-Resistant Sodium Channels

A physiological mechanism, the expression of TTX-resistant sodium channels in skeletal muscle, is identified, responsible for adaptive diversification in whole-animal resistance to tetrodotoxin in Thamnophis sirtalis.


  • D. Stern
  • Biology
    Evolution; international journal of organic evolution
  • 2000
This approach will assist in the task of identifying the specific mutations generating phenotypic variation and elucidating how they alter gene function, which will provide the current missing link between molecular and phenotypesic variation in natural populations.

Patterns of evolutionary rate variation among genes of the anthocyanin biosynthetic pathway.

It is reported here that upstream genes in the anthocyanin pathway have evolved substantially more slowly than downstream genes and it is suggested that this difference in evolutionary rates may be explained by upstream genes being more constrained because they participate in several different biochemical pathways.

Different genes underlie adaptive melanism in different populations of rock pocket mice

Results indicate that adaptive melanism has arisen at least twice in C. intermedius and that these similar phenotypic changes have a different genetic basis.

Parallel Evolution and Inheritance of Quantitative Traits

It is suggested that influence of shared genetic biases should be detectable by the disproportionate use of the same genes in independent instances of parallel phenotypic evolution, and shown how progress can be made through simple tests of parallel inheritance of genetic differences: similar additive, dominance, and epistasis components in analysis of line means and similar effective numbers of loci.


The geographic pattern of genetically determined TTX resistance in the garter snake Thamnophis sirtalis over much of the range of its ecological interaction with toxic newts of genus Taricha is investigated, providing dramatic evidence that geographic structure is an important component in coevolutionary interactions between predators and prey.

Convergent Evolution on the Molecular Level

  • H. Zakon
  • Biology
    Brain, Behavior and Evolution
  • 2002
The types of convergent molecular evolution, the criteria for accepting or rejecting convergence, and some examples relevant to neurobiology where convergence has been claimed are discussed, including convergence of opsins, gap junction proteins, neurotransmitter receptors, ion channels, and venoms directed against ion channels.