Evolution and Expression Patterns of Genes in : Phylogenetic Insights for Floral Symmetry Genes in Asteraceae.

Homologs of the gene family have been independently recruited many times across the eudicots to control aspects of floral symmetry The family Asteraceae exhibits the largest known diversification in this gene paralog family accompanied by a parallel morphological floral richness in its specialized head-like inflorescence. In Asteraceae, whether or not gene floral symmetry function is preserved along organismic and gene lineages is unknown. In this study, we used phylogenetic, structural and expression analyses focused on the highly derived genus (tribe Anthemidae) to address this question. Phylogenetic reconstruction recovered eight main gene lineages present in Asteraceae: two from , four from and two from -like genes. The species phylogeny was recovered in most of the gene lineages, allowing the delimitation of orthologous sets of genes in Asteraceae. Quantitative real-time PCR analysis indicated that in three of the four isolated genes are more highly expressed in ray flowers. The expression of the four genes overlaps in several organs including the ligule of ray flowers, as well as in anthers and ovules throughout development.