Abstract Detail

Systematics Section/ASPT

McCarthy, Elizabeth [1], Landis, Jacob [2], Litt, Amy [1].

Does reconstructing ancestral progenitor phenotypes alter the interpretation of morphological evolution in allopolyploids?

Allopolyploidization, the combination of interspecific hybridization and multiplication of chromosome number, is prevalent in angiosperms. Comparisons of allopolyploids to their diploid progenitors has shown that this process can result in phenotypes unlike either progenitor. In previous studies, the extant taxa most closely related to those involved in the polyploidization event were used as the progenitors. However, both allopolyploids and the diploid species that created them have been evolving since the polyploidization event. We hypothesize that using the phenotypes of extant diploid species for comparison with those of polyploids introduces bias into the interpretation of polyploid evolution. We further hypothesize that this will be especially evident in older polyploids because there has been additional time for phenotypic divergence to occur. We test these hypotheses by using ancestral state reconstructions to estimate progenitor phenotypes at the time of polyploid origin, and by comparing these results to those of standard methods using extant species as progenitors. The genus Nicotiana (Solanaceae) is variable in floral morphology and color, and approximately half of its species are allotetraploids. These range in age from Nicotiana. We evaluate whether the evolution of these traits is constrained by phylogeny, or whether similar traits evolve multiple times independently. We also determine whether shifts in different floral traits co-occur in order to establish whether suites of floral characters tend to evolve together. Our results shed light on the consequences of polyploidy, a key process in plant evolution, and how polyploidy contributes to diversity in floral form.

1 - University of California, Riverside, Department of Botany and Plant Sciences, 900 University Ave., Riverside, CA, 92521, USA
2 - University Of Florida, Dept Of Biology, Florida Museum Of Natural History - Dickinson Hall, Museum Road And Newell Drive, Gainesville, FL, 32611, USA

Keywords:
Polyploidy
hybridization
floral evolution
ancestral state reconstruction
Nicotiana.

Presentation Type: Oral Paper:Papers for Sections
Session: 49
Location: Salon 4/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 3:45 PM
Number: 49009
Abstract ID:748
Candidate for Awards:Margaret Menzel Award