| Abstract Detail
The Hills are Alive: Ecology and Evolution of the Intermountain West Flora Rushworth, Catherine [1]. The evolution and ecology of apomixis in Boechera of the Northern Rocky Mountains. Species boundaries among flowering plants are routinely blurred by hybridization, apomixis (asexual reproduction via seed), and polyploidy. These phenomena co-occur with such high frequency that collectively they are often known as “the taxonomist’s nightmare,” as they confound attempts to delimit many taxa. Yet little is known about the evolutionary forces that ultimately create and shape them. How are phenotypes affected by these traits, either collectively or individually? What ecological factors shape selection on these phenotypes? What are the impacts of transitions to apomixis on fitness, and how often do these transitions occur? I examine these questions using the mustard genus Boechera, a wildflower native across western North America that has frustrated botanists since the early 1900s. While the majority of the roughly 80 diploid sexual Boechera species are highly self-fertilizing, outcrossing occurs both within and between species, and is correlated with transitions to both polyploid or diploid apomixis. This offers a unique opportunity to separately examine the evolution of apomixis, polyploidy, and interspecific hybridization.
A large-scale reciprocal transplant experiment shows that apomict fitness is higher than sexual fitness, and that this difference is due to increased overwinter survival of asexuals, implicating abiotic selection. However, insect herbivory is significantly higher in hybrid asexuals, suggesting that biotic selection on hybridization may limit the spread of apomixis across populations. Thus, ecological complexity plays a key role in the evolution of each trait individually. Altogether, this work shows that the fitness effects of outcrossing and asexuality are varied and trait-dependent, and have profound impacts on patterns of species divergence across the group.
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Related Links:
Website of Cathy Rushworth
1 - University of Minnesota, Department of Plant and Microbial Biology, 1500 Gortner Ave, St. Paul, MN, 55108, USA
Keywords:
evolution of sex
hybridization
apomixis
Boechera
evolutionary ecology.
Presentation Type: Symposium Presentation
Session: SY5, The Hills are Alive: Ecology and Evolution of the Intermountain West Flora
Location: /
Date: Thursday, July 22nd, 2021
Time: 1:30 PM(EDT)
Number: SY5009
Abstract ID:387
Candidate for Awards:None |
