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Pleiotropy, redundancy and the evolution of flowers
Victor A Albert1, David G Oppenheimer, Charlotte Lindqvist
1Natural History Museums and Botanical Garden, University of Oslo, Sarś gate 1, N-0562 Oslo, Norway. victor.albert@nhm.uio.no
Trends in Plant Science
|July 18, 2002
Summary
Flowering plants evolved bisexual flowers due to a gene duplication event. The LEAFY (LFY) gene
Area of Science:
- Evolutionary developmental biology
- Plant reproductive biology
Background:
- Most angiosperms possess bisexual flowers with enclosed ovules, a trait absent in their gymnosperm ancestors.
- Phylogenetic data indicates flowering plant lineage predates the evolution of flowers.
Purpose of the Study:
- To propose a model explaining the evolutionary origin of bisexual flowers in angiosperms.
- To investigate the role of gene duplication and regulation in flower development.
Main Methods:
- Phylogenetic analysis to reconstruct evolutionary history.
- Gene regulatory network modeling to simulate evolutionary pressures.
- Analysis of the LEAFY (LFY) gene and its paralogs in extant species.
Main Results:
- A model suggests positive selection on a duplicated gene 'trapped' ancestral plants into a bisexual state ~130 million years ago.
- The LEAFY (LFY) gene acts as a master regulator connecting environmental signals to reproductive development.
- Elimination of an LFY paralog, retained in gymnosperms, correlates with the sudden appearance of flowers in the fossil record.
Conclusions:
- Gene duplication and subsequent regulatory changes, specifically involving the LFY gene, were pivotal in the evolution of angiosperm flowers.
- This provides a mechanistic explanation for the rapid transition to bisexual flower structures.