Journal Article

Testing Founder Effect Speciation: Divergence Population Genetics of the Spoonbills Platalea regia and Pl. minor (Threskiornithidae, Aves)

Carol K. L. Yeung, Pi-Wen Tsai, R. Terry Chesser, Rong-Chien Lin, Cheng-Te Yao, Xiu-Hua Tian and Shou-Hsien Li

in Molecular Biology and Evolution

Published on behalf of Society for Molecular Biology and Evolution

Volume 28, issue 1, pages 473-482
Published in print January 2011 | ISSN: 0737-4038
Published online August 2010 | e-ISSN: 1537-1719 | DOI: https://dx.doi.org/10.1093/molbev/msq210
Testing Founder Effect Speciation: Divergence Population Genetics of the Spoonbills Platalea regia and Pl. minor (Threskiornithidae, Aves)

More Like This

Show all results sharing these subjects:

  • Evolutionary Biology
  • Molecular and Cell Biology

GO

Show Summary Details

Preview

Although founder effect speciation has been a popular theoretical model for the speciation of geographically isolated taxa, its empirical importance has remained difficult to evaluate due to the intractability of past demography, which in a founder effect speciation scenario would involve a speciational bottleneck in the emergent species and the complete cessation of gene flow following divergence. Using regression-weighted approximate Bayesian computation, we tested the validity of these two fundamental conditions of founder effect speciation in a pair of sister species with disjunct distributions: the royal spoonbill Platalea regia in Australasia and the black-faced spoonbill Pl. minor in eastern Asia. When compared with genetic polymorphism observed at 20 nuclear loci in the two species, simulations showed that the founder effect speciation model had an extremely low posterior probability (1.55 × 10−8) of producing the extant genetic pattern. In contrast, speciation models that allowed for postdivergence gene flow were much more probable (posterior probabilities were 0.37 and 0.50 for the bottleneck with gene flow and the gene flow models, respectively) and postdivergence gene flow persisted for a considerable period of time (more than 80% of the divergence history in both models) following initial divergence (median = 197,000 generations, 95% credible interval [CI]: 50,000−478,000, for the bottleneck with gene flow model; and 186,000 generations, 95% CI: 45,000−477,000, for the gene flow model). Furthermore, the estimated population size reduction in Pl. regia to 7,000 individuals (median, 95% CI: 487−12,000, according to the bottleneck with gene flow model) was unlikely to have been severe enough to be considered a bottleneck. Therefore, these results do not support founder effect speciation in Pl. regia but indicate instead that the divergence between Pl. regia and Pl. minor was probably driven by selection despite continuous gene flow. In this light, we discuss the potential importance of evolutionarily labile traits with significant fitness consequences, such as migratory behavior and habitat preference, in facilitating divergence of the spoonbills.

Keywords: founder effect speciation; spoonbills; Platalea; postdivergence gene flow; approximate Bayesian computation

Journal Article.  6254 words.  Illustrated.

Subjects: Evolutionary Biology ; Molecular and Cell Biology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content. subscribe or login to access all content.