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Patterns of polymorphism resulting from long-range colonization in the Mediterranean conifer Aleppo pine
Delphine Grivet1, Federico Sebastiani, Santiago C González-Martínez
1Department of Forest Systems and Resources, Forest Research Institute, CIFOR-INIA, Madrid, Spain.
The New Phytologist
|September 8, 2009
Summary
Pinus halepensis experienced severe genetic bottlenecks and diversity loss during range shifts. Natural selection likely drove adaptation in western populations facing new environments, shaping distinct evolutionary units crucial for forest conservation.
Area of Science:
- Evolutionary Biology
- Ecology
- Genetics
Background:
- Evolutionary outcomes are shaped by species-specific factors and interacting evolutionary forces.
- Understanding range shifts in widespread species is key to predicting their adaptive potential.
Purpose of the Study:
- To investigate the demographic history and genetic polymorphism patterns of drought tolerance genes in Pinus halepensis.
- To identify signatures of selection and infer evolutionary processes across the species' range.
Main Methods:
- Utilized chloroplast simple sequence repeats (cpSSRs) and nuclear gene coalescence modeling for demographic inference.
- Analyzed polymorphism patterns in ten drought-response candidate genes, testing for selection under demographic scenarios.
Main Results:
- Observed significant genetic diversity loss from Greek relictual populations westward, with evidence of strong bottlenecks.
- Detected an excess of derived polymorphisms in western populations, suggesting natural selection on newly colonized areas.
- Identified distinct evolutionary units resulting from range expansions and contractions.
Conclusions:
- Wide-ranging expansions and contractions in forest trees lead to strong selective pressures and differentiated evolutionary units.
- This research provides critical insights for forest conservation and management strategies under climate change.
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