Evolutionary Developmental Biology (Evo-Devo)
Howarth, Dianella G. , Donoghue, Michael J. .
Phylogeny and expression of DIV-like and RAD-like genes (MYB transcription factors) and their role in floral symmetry shifts in Dipsacales and core eudicots.
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 and across eudicots also provides a framework for ascertaining the phylogenetic placement of duplications in these gene lineages. These MYB gene families appear to also duplicate before the diversification of the core eudicots, similarly to CYC-like genes. Additionally, multiple duplications within Dipacales indicate that there are extra copies, with diversified expression, in Caprifoliaceae (with bilaterally symmetric flowers). We will discuss our phylogenetic and expression data from DIV-like and RAD-like genes and how these might have played a role in the evolution of floral form in the Dipsacales and core eudicots.
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1 - St. John\'s University, Biological Sciences, 8000 Utopia Pkwy, St. Albert Hall 257, Queens, NY, 11439
2 - Yale University, Department Ecology & Evolutionary Biology, Po Box 208105, New Haven, Connecticut, 06520-8105, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Wednesday, July 30th, 2008
Time: 11:00 AM