Polyploidization and Sex Chromosome Evolution in Amphibians

  • Ben J. Evans
  • R. Alexander Pyron
  • John J. Wiens


Genome duplication, including polyploid speciation and spontaneous polyploidy in diploid species, occurs more frequently in amphibians than mammals. One possible explanation is that some amphibians, unlike almost all mammals, have young sex chromosomes that carry a similar suite of genes (apart from the genetic trigger for sex determination). These species potentially can experience genome duplication without disrupting dosage stoichiometry between interacting proteins encoded by genes on the sex chromosomes and autosomal chromosomes. To explore this possibility, we performed a permutation aimed at testing whether amphibian species that experienced polyploid speciation or spontaneous polyploidy have younger sex chromosomes than other amphibians. While the most conservative permutation was not significant, the frog genera Xenopus and Leiopelma provide anecdotal support for a negative correlation between the age of sex chromosomes and a species’ propensity to undergo genome duplication. This study also points to more frequent turnover of sex chromosomes than previously proposed, and suggests a lack of statistical support for male versus female heterogamy in the most recent common ancestors of frogs, salamanders, and amphibians in general. Future advances in genomics undoubtedly will further illuminate the relationship between amphibian sex chromosome degeneration and genome duplication.


Dosage Compensation Recent Common Ancestor Polyploid Species Most Recent Common Ancestor Ancestral Reconstruction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We are particularly grateful to Barbara Mable who provided a comprehensive critical assessment of an earlier version of this chapter. We also thank Liam Revell for advice and assistance with the R package “phytools” and Jim Bogart and Ben Bolker for comments.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Ben J. Evans
    • 1
  • R. Alexander Pyron
    • 2
  • John J. Wiens
    • 3
  1. 1.Department of BiologyMcMaster UniversityHamiltonCanada
  2. 2.Department of Biological SciencesThe George Washington UniversityWashingtonUSA
  3. 3.Department of Ecology and EvolutionStony Brook UniversityStony BrookUSA

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