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Abstract Detail


Evolutionary Developmental Biology (Evo-Devo)

Jaramillo, M. Alejandra [1], Kramer, Elena M [2].

Molecular evolution of the petal and stamen identity genes, APETALA3 and PISTILLATA, after petal loss in the Piperales.

The loss of organs and physiological capacities has been common throughout evolution. Following such losses, we may expect purifying selection to be relaxed on genes previously involved in the production of lost features. Maybe the most striking example in the angiosperms is the loss of photosynthetic capacities in parasitic plants. Perianth organs, petals and sepals, have also been lost several times during the evolutionary history of flowering plants. The Piperales, a basal lineage of angiosperms that includes the perianthless (with no petals or sepals) families Piperaceae and Saururaceae as well as the Aristolochiaceae, which exhibit a well-developed perianth, provides a unique opportunity to study the evolution of petal identity genes in relation to petal loss. We examined the evolution of the petal and stamen identity genes, APETALA3 and PISTILLATA. We used an exemplar sampling from across the basal lineages of angiosperms, including at least one species of each family in the Piperales, except for Lactoridaceae and Hydnoraceae for which flower material was not available. We provide evidence for relaxation of selection on the putative petal and stamen identity genes, following the loss of petals in the Piperales. Our results are particularly interesting as the B-class genes are not only responsible for the production of petals but are also central to stamen identity, that show no modification in these plants. Relaxed purifying selection after the loss of only one of these organs suggests that there has been dissociation of the functional roles of these genes in the Piperales.


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1 - University of Missouri-Columbia, Biological Sciences, 109 TUcker Hall, Columbia, Missouri, 652011, USA
2 - Harvard University, Organismic and Evolutionary Biology, 16 Divinity Ave, Biolabs 1109 , Cambridge, MA, 02138, USA

Keywords:
B class genes
Piperales.

Presentation Type: Oral Paper:Papers for Topics
Session: CP46
Location: Astoria Room/Hilton
Date: Wednesday, July 11th, 2007
Time: 11:15 AM
Number: CP46008
Abstract ID:1934


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