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Abstract Detail


Evolutionary Developmental Biology (Evo-Devo)

Wu, Cheng-Chiang [1], Mathews, Sarah [2], Magallón, Susana [3], Kramer, Elena M [4].

Evolutionary Dynamics of Floral Homeotic MADS-box Gene Lineages in Angiosperms.

Transcriptional regulatory networks control the development of organisms. Many of these networks have evolved through extensive duplication of transcription factor modules. The ABCE class genes of MADS-box transcription factors, which can form dimers or multimers and determine floral organ identity in angiosperms, constitute a unique system to study the functional evolution of genetic modules. Phylogenetic analyses suggested that coincident duplication events occurred in the APETALA1 (AP1), APETALA3 (AP3), AGAMOUS (AG), and SEPALLATA (SEP) lineages of MADS-box family transcription factors in close association with the emergence of the core eudicot clade. This cluster of duplications is also correlated with frameshift events in the coding regions of the resultant euAP3 and euAP1 orthologous lineages, giving rise to lineage-specific motifs at the C-terminal end. However, previous studies lacked the thorough sampling that would allow precise dating and analysis of natural selection. We have identified homologs of the AP1, AP3, AG, and SEP lineages, as well as the PISTILLATA (PI) lineage, from representative taxa closely before and after the major gene duplications, including Gunnera manicata (Gunneraceae). Phylogenetic analyses of selected MADS-box genes from 40 representative families of seed plants indicated that this cluster of major duplications predated the rise of Gunneraceae, which is sister to the core eudicot clade. We use approaches with multiple calibration points to precisely date these gene duplications. We also utilize tests of molecular evolution to assess the natural selection underlying the evolution of these gene lineages. This research provides further understanding of evolutionary dynamics of floral homeotic MADS-box gene lineages in light of functional evolution.


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1 - Harvard University, Organismic and Evolutionary Biology, 16 Divinity Ave, Biolabs 1112 , Cambridge, MA, 02138, USA
2 - Harvard University, Arnold Arboretum, Harvard University Herbaria, 22 Divinity Ave, Cambridge, MA, 02138, USA
3 - Instituto de Biología, Universidad Nacional Autónoma de México,, 3er Circuito de Ciudad Universitaria,, Del. Coyoacán, México D.F. 04510, Mexico
4 - Harvard University, Organismic and Evolutionary Biology, 16 Divinity Ave, Biolabs 1109 , Cambridge, MA, 02138, USA

Keywords:
MADS-box gene
gene duplication
Angiosperms.

Presentation Type: Oral Paper:Papers for Topics
Session: 53
Location: 101/Law
Date: Wednesday, July 30th, 2008
Time: 11:15 AM
Number: 53011
Abstract ID:865


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