Partitioning adaptive differentiation across a patchy landscape: shade avoidance traits in Impatiens capensis

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
David L. Remington, Associate Professor (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: Adaptation to different habitat types across a patchy landscape may either arise independently in each patch or occur due to repeated colonization of each patch by the same specialized genotype. We tested whether open- and closed-canopy forms of Impatiens capensis, an herbaceous annual plant of eastern North America, have evolved repeatedly by comparing hierarchical measures of FST estimated from AFLPs to morphological differentiation measured by QST for five pairs of populations found in open and closed habitats in five New England regions. Morphological differentiation between habitats (QHT) in elongation traits was greater than marker divergence (FHT), suggesting adaptive differentiation. Genotypes from open- and closed-canopy habitats differed in shade avoidance traits in several population pairs, whereas patterns of AFLP differentiation suggest this differentiation does not have a single origin. These results suggest that open- and closed-canopy habitats present different selective pressures, but that the outcome of diversifying selection may differ depending on specific closed- and open-canopy habitats and on starting genetic variation. Hierarchical partitioning of FST and QST makes it possible to distinguish global stabilizing selection on traits across a landscape from diversifying selection between habitat types within regions.

Additional Information

Evolution, 62(3), 654-667
Language: English
Date: 2008
FST-QST, parallel evolution, phenotypic plasticity, population differentiation, shade avoidance

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