Evolutionary Developmental Biology (Evo-Devo)
Howarth, Dianella G. , Donoghue, Michael J. .
Phylogeny and expression of TCP and MYB genes and their role in floral symmetry shifts in Dipsacales.
Recent evidence has indicated that the interplay of TCP and MYB transcription factors act to confer dorsal/ventral patterning in flowers. In the Antirrhineae (snapdragon and itís relatives), knockouts of CYCLOIDEA (CYC) and DICHOTOMA (DICH) from the TCP family, or RADIALIS (RAD) from the MYB family, result in fully ventralized radially symmetrical flowers, while a knockout of DIVARICATA (DIV) from the MYB family results in a dorsalized radially symmetrical flower. An increasing number of studies from across eudicots suggest that orthologous TCP genes may be similarly important in dorsal identity in other groups, while MYB genes have not yet been examined. Our work in the Dipsacales (honeysuckles and relatives) is aimed at providing a model clade to examine the role of these gene families in the evolution of different flower symmetries. Within Dipsacales TCP genes are duplicated in two of the major gene lineages along the line leading to the Caprifoliaceae, correlated with the origin of bilaterally symmetrical flowers. Similar duplications are becoming apparent in MYB genes as well. A thorough analysis of these genes in Dipsacales also provides a framework for ascertaining the phylogenetic placement of duplications in these gene lineages. For example, bayesian analyses have uncovered a novel core eudicot gene, sister to the CYC lineage, which also appears to be important in dorsal/ventral patterning. We will discuss our phylogenetic and expression data from these gene families and how these might have played a role in the evolution of floral form in the Dipsacales, focusing especially on the MYB genes, DIV and RAD.
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1 - Yale University, Department Ecology & Evolutionary Biology, Po Box 208105, New Haven, Connecticut, 06520-8105, USA
2 - Yale University, Ecology & Evolutionary Biology and Peabody Museum of Natural History, PO Box 208106, New Haven, CT, 06520-8106, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Astoria Room/Hilton
Date: Wednesday, July 11th, 2007
Time: 10:45 AM