Abstract Detail

Molecular Ecology and Evolution

Misiewicz, Tracy [1], Fine, Paul [2].

Ecological divergence across a mosaic of soils in the Amazonian tree Protium subserratum (Burseraceae).

Disruptive natural selection across edaphic gradients can lead to adaptive divergence between plant populations. While this has been demonstrated in temperate plant systems the role of edaphic heterogeneity in generating and maintaining tropical tree diversity is still unknown. We examined genetic and morphological differentiation among adjacent populations of the tropical tree Protium subserratum found on white-sand, brown-sand and clay soils in the Peruvian lowland Amazon. Nuclear microsatellites and vegetative morphology were used to (1) Quantify the extent of phenotypic and genetic divergence across edaphic boundaries (2) Assess the importance of natural selection vs. drift in population level divergence (3) Determine the extent of hybridization across soil types (4) Estimate migration rates among populations. We found that both phenotypic and genetic variation were correlated with soil type. Higher levels of genetic differentiation and lower migration rates were observed between parapatric populations from different soil types than between geographically distant populations from the same soil type. Comparisons of phenotypic differentiation and neutral genetic variation indicate a role for natural selection in driving population differentiation among soil types and hybrids were detected at low frequencies suggesting that gene flow among these edaphically specialized populations may occur at low frequencies. Overall, our results suggest that specialization onto different soil types has occurred multiple times in P. subserratum and that divergent natural selection across soil gradients may be important in driving and maintaining Amazonian tree diversity.  

1 - University of California, Berkeley, Integrative Biology, 3060 Valley Life Sciences Building #3140, Berkeley, CA, 94720, USA
2 - University of California, Berkeley, Integrative Biology, 3060 Valley Life Sciences Building #3140, Berkeley, CA, 94720, USA

Keywords:
Tropical Tree
ecological divergence
Adapatation
Amazon
Edaphic specializatin.

Presentation Type: Oral Paper:Papers for Topics
Session: 28
Location: Firs South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 3:00 PM
Number: 28007
Abstract ID:791
Candidate for Awards:Margaret Menzel Award