Presentation Detail

Genetic Drift and/or Neutral Evolution

de Brito Martins, Ayana [1], de Aguiar, Marcus [2], Bar-Yam, Yaneer [3].

Evolution and Stability of Ring Species.

Ring species arise when organisms spread around a geographical ring in such a way that the two ends of the population, which meet after many generations, are reproductively isolated, despite on-going gene flow around the ring. Whereas geographic barriers that separate subpopulations have long been considered a key factor in establishing reproductive isolation, speciation in a homogeneous environment is also possible under certain conditions. Ring species are a distinct intermediate case between single and multiple species, providing a unique test of our understanding of the role of geography in speciation. Here we investigate the effect of barriers on biodiversity by simulating the evolution of ring species using an agent-based neutral model with local sexual reproduction,mutation and dispersal. We show that the distribution of subspecies, the principal components of genetic diversity and the linear spatial-genetic correlation of our simulations match the observed data for the greenish warblers̢۪ complex, a well-documented example of an actual ring species in nature,even though selection is expected to be important for traits of this species. Decreasing the habitable area of the region of secondary contact increases genetic fluctuations there and facilitates the reversal of incomplete speciation, demonstrating the decisive role played by landscape features. We find that, although ring species are often unstable to speciation or mixing, for the greenish warblers the expanded area near the point of secondary contact may be important for extending the duration of the ring, and thus for the opportunity to observe this ring species. Our results suggest that simulations can be used as a basis for understanding the dynamics of expansion of single species, multiple species, and ring species by describing empirical data for complex spatial-genetic traits.

1 - Universidade de São Paulo, Departamento de Ecologia Geral, Instituto de Biociências, Rua do Matão, 321 - Trav. 14, sala 243, Cidade Universitária, São Paulo, SP, 05508-900, Brazil
2 - Universidade Estadual de Campinas, Departamento de Física do Estado Sólido e Ciência dos Materiais, Instituto de Física Gleb Wataghin, Sala 211, Campinas, SP, 13083-970, Brazil
3 - New England Complex Systems Institute, 238 Main Street, Suite 319, Cambridge, MA, 02142, USA

Keywords:
neutral evolution
individual-based model
biodiversity
Isolation by distance
reproductive isolation
Speciation.

Presentation Type: Regular Oral Presentation
Session: 82
Location: Peruvian B/Snowbird Center
Date: Sunday, June 23rd, 2013
Time: 2:15 PM
Number: 82004
Abstract ID:58
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation