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Speciation in Drouetia: evidence of punctuated equilibrium?

The theory of punctuated equilibria, derived from palaeontological evidence, sustains that evolution proceeds by episodic changes followed by long periods of stasis. Two of the assumptions of the theory are a) that reproductive isolation is linked to morphological change and b) that speciation follows the peripatric model; however, the first assumption can only be tested in living systems and geologic time lacks the fine resolution to track the small, ephemeral, localized changes that characterize the diversification periods. Support for the aforementioned assumptions can only come from extant taxa and from them the fine resolution of short time change can be detected as well. To see it in living taxa, one should spread the time axis two-dimensionally, that is: select a perfectly contained clade whose members can be assigned to discrete time frames.
The model predicts that the members of the clade living in older, stable areas will exhibit less intraspecific diversity and be genetically less close interspecifically (stasis), whereas those living in younger, perturbed areas will be intraspecifically more diverse although genetically closer interspecifically (diversification). The Azores islands, with ages ranging from 250.000 to 8 million years and recent, recorded volcanic activity as well, provide the geological framework. The endemic molluscan subgenus Drouetia , which anatomy and morphology varies according to the ages of the islands, assures the biological settings to test punctuated equilibrium in a living system. For the purpose of relating the observed anatomical and morphological variation to the theory of punctuated equilibrium, the project intends, using also the molecular approach, a) to establish a phylogeny and a phylogeography for Drouetia, and b) to correlate morphology with genetics, and diversity with phylogeography.

Team
Principal Investigator
António Frias Martins

António Frias Martins

Position: Full Professor
Group:
BIOISLE
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Researchers
David James Alexander Edward Harris

David James Alexander Edward Harris

Position: Principal Researcher
Group:
AP
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Nuno Miguel dos Santos Ferrand de Almeida

Nuno Miguel dos Santos Ferrand de Almeida

Position: Full Professor
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Other members
Armindo Rodrigues, Thierry Backeljau, Robert Cameron, Paulo Melo
State
Concluded
Proponent Institution
Instituto de Ciências e Tecnologias Agrárias e Agro-Alimentares - Porto (ICETA-Porto/UP)
Funded by
FCT, COMPETE
Dates
2008 (Duration: 3 years)
Participant Institutions
Centro de Investigação em Biodiversidade de Recursos Genéticos (CIBIO/ICETA-Porto/UP), Universidade dos Açores (UAçores)
Reference
PTDC/BIA-BDE/73467/2006
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