Developmental and Structural Section
Bissell, Erin , Diggle, Pamela K. .
Modular genetic architecture of floral morphology in Nicotiana: comparative phenotypic and quantitative genetic approaches to floral integration.
Animal-pollinated flowers are complex structures that may require a precise configuration of floral organs for proper function. As such, they represent an excellent system with which to test hypotheses regarding the role of phenotypic integration and modularity in morphological evolution. Nicotiana alata and N. forgetiana are two closely related species of wild tobacco that differ dramatically in floral size and shape. Morphological differences in the flowers of each species correspond to their predominant pollinators, which are hawkmoths and hummingbirds respectively. We use comparative phenotypic and quantitative genetic approaches to examine correlations among floral characters in N. alata, N. forgetiana and their artificial F4 hybrids. Flowers of both species share basic patterns of phenotypic and genetic correlations characterized by at least two integrated character suites that are relatively independent of each other and are not disrupted by four generations of recombination in hybrids. One suite includes characters of the corolla limb, which likely are involved in pollinator attraction; the other includes characters of the corolla tube, which likely are involved in pollen transfer. We conclude that these integrated character suites represent phenotypic modules that are the product of modular genetic architecture. Intra-floral modularity may have been critical for rapid specialization of these species to different pollinators.
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1 - University of Colorado, Department of Ecology and Evolutionary Biology, UCB 334, Boulder, Colorado, 80309, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 3:00 PM