| Abstract Detail
Evolutionary Development Friedman, William E. [1]. An evolutionary-developmental perspective on the angiosperm reproductive syndrome. After more than a century of fairly static, if not dogmatic, thought about the diversification of flowering plants, we are in the midst of a fundamental rewrite of their evolutionary and developmental history. Angiosperms possess a unique suite of reproductive characteristics that includes a highly reduced female gametophyte, a process of double fertilization, and the production of a genetically biparental embryo-nourishing tissue, endosperm. Contrary to received wisdom, recent embryological investigations of ancient angiosperm lineages indicate that the first flowering plants may not have produced a triploid endosperm derived from a Polygonum-type embryo sac. Importantly, studies of ancient angiosperm lineages reveal that the angiosperm female gametophyte is a fundamentally modular entity, and that evolutionary transitions in the number and developmental patterning of these modular subunits directly alter the genetic constitution of endosperm. Thus, the evolution of endosperm ploidy, maternal to paternal genomic ratios, levels of heterozygosity, and degrees of genetic conflict (vis à vis its role in interparental conflict and/or parent-offspring conflict) is directly tied to the expression of underlying modular components of the female gametophyte. The key is to understand female gametophyte diversity based on general principals of developmental biology (e.g. modularity, ectopic expression, and heterochrony), and to link this diversity to evolutionary innovations (perhaps even adaptations) associated with changes in endosperm genetics.
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1 - University of Colorado, Ecology and Evolutionary Biology, Boulder, CO, 80309, USA
Keywords:
female gametophyte
endosperm
modularity
evo-devo
double fertilization
inclusive fitness theory.
Presentation Type: ASPB Major Symposium
Session: S04
Location: International Ballroom/Hilton
Date: Monday, July 9th, 2007
Time: 2:00 PM
Number: S04001
Abstract ID:1285 |
