Journal of Molecular Evolution

, Volume 58, Issue 2, pp 145–153

Adaptive Evolution of Scorpion Sodium Channel Toxins


DOI: 10.1007/s00239-003-2534-2

Cite this article as:
Zhu, S., Bosmans, F. & Tytgat, J. J Mol Evol (2004) 58: 145. doi:10.1007/s00239-003-2534-2


Gene duplication followed by positive Darwinian selection is an important evolutionary event at the molecular level, by which a gene can gain new functions. Such an event might have occurred in the evolution of scorpion sodium channel toxin genes (α- and β-groups). To test this hypothesis, a robust statistical method from Yang and co-workers based on the estimation of the nonsynonymous-to-synonymous rate ratio (ω = dN/dS) was performed. The results provide clear statistical evidence for adaptive molecular evolution of scorpion α- and β-toxin genes. A good match between the positively selected sites (evolutionary epitopes) and the putative bioactive surface (functional epitopes) indicates that these sites are most likely involved in functional recognition of sodium channels. Our results also shed light on the importance of the B-loop in the functional diversification of scorpion α- and β-toxins.


Gene duplication Positive Darwinian selection Likelihood ratio test Scorpion toxin Sodium channel Evolutionary epitopes 

Copyright information

© Springer-Verlag New York Inc. 2004

Authors and Affiliations

  1. 1.Laboratory of ToxicologyUniversity of Leuven, E. Van Evenstraat 4, 3000 LeuvenBelgium

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