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Abstract Detail

Molecular Ecology and Evolution

Laport, Robert G. [1], Pilson, Diana [2].

Is Polyploid Speciation in the Southwestern Desert Creosote Bush (Larrea tridentata; Zygophyllaceae) Facilitated by Pollinator Discrimination?

Polyploidy, the duplication of all chromosomes in an organism’s genome, is extremely common in angiosperms. The prevalence of polyploidy implies a significant role for genome duplication in modulating evolutionary trajectories and botanical biodiversity. Plants with increased chromosome complements differ in traits typically associated with local adaptation, which can lead to population divergence. However, diploids and polyploids also usually interbreed poorly, suggesting intrinsic genetic mechanisms figure prominently in polyploid speciation. Thus, it remains unclear if polyploidy facilitates ecological adaptation or simply imposes an intrinsic reproductive barrier among populations. We are employing an integrative approach to assess ecological differences and reproductive interactions in creosote bush (Larrea tridentata; Zygophyllaceae), a common southwestern desert plant comprising populations with three ploidy levels, to distinguish between these alternatives. Using previously identified areas where the ploidy levels of creosote bush co-occur, we are addressing three questions: (1) Do flower sizes differ among ploidy levels?, (2) Do bees carry pollen between plants differing in chromosome number?, and (3) Do crosses between cytotypes result in live hybrids? Understanding how one species becomes two is crucial to understanding patterns of biodiversity and the functioning of ecological systems. Results from this study will help elucidate the evolutionary significance of polyploidy to ecological adaptation, incipient speciation, and patterns of biodiversity in many species, but will also contribute to understanding the ecology of an important plant species and its native pollinators in sensitive North American desert biomes.

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1 - University Of Nebraska-Lincoln, School Of Biological Sciences, 348 Manter Hall, Lincoln, NE, 68588, USA
2 - University of Nebraska, School of Biological Sciences, 348 Manter Hall, Lincoln, NE, 68588-0118, USA

flow cytometry
population dynamics
pollinator isolation.

Presentation Type: Oral Paper:Papers for Topics
Session: 11
Location: Firs North/Boise Centre
Date: Monday, July 28th, 2014
Time: 4:00 PM
Number: 11010
Abstract ID:135
Candidate for Awards:None

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