Evolutionary Developmental Biology (Evo-Devo)
Zhong, Jinshun , Kellogg, Elizabeth A. .
Floral diversity and evolution within the Lamiaceae s.l.
Biologists have long sought to understand the evolution of morphological diversity. Here we plan to incorporate developmental, genetic and phylogenetic data, to explain the evolution and diversification of floral form. Lamiaceae (the mint family) exhibits considerable variation of floral forms, and such variation has made the reconstruction of ancestral states of such traits ambiguous. Early developmental data and information on gene expression might help understand the floral characters better. CYC, RAD and DIV are key proteins in floral symmetry patterning; we hypothesize that spatial and temporal variation in their copy number and expression pattern will correlate with variation in floral form, and thus the evolution of flower shape. Therefore, in this study, we focus on adding developmental data to reconstruct the ancestral state of floral form, and incorporating genetic and developmental data to explain the diversity and evolution of floral form within Lamiaceae. Up to now, three species have been examined to get a series of developmental stages using Scanning Electron Microscopy (SEM). Callicarpa seems to be truly actinomorphic all the way through from early to late stages. Teucrium has a 0/5-bilabiate corolla as an adult, but actually has a 2/3-bilabiate corolla at early developmental stages. The flower of Mentha is apparently zygomorphic during early developmental stages, and the flowers switch to be actinomorphic due to late organ growth in the abaxial zones. The preliminary results indicate that developmental data will greatly help to clarify the character polarity of floral form. Furthermore, five out of seven subfamilies of Lamiaceae plus the genus Callicarpa have been sampled for the phylogenetic reconstruction of the CYC gene family; without representatives from Ajugoideae and Symphorematoideae. A duplication event that led to two major clades (CYC2A and CYC2B), has occurred at some point before the divergence of “core Lamiaceae”, raising the possibility that this duplication may be responsible in part for the diversity of floral forms in the family.
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1 - University of Missouri-St. Louis, Department of Biology, One University Boulevard, St. Louis, Missouri, 63121, USA
2 - University of Missouri Saint Louis, Biology, One University Blvd, Research Building, Saint Louis, MO, 63121, USA
Presentation Type: Oral Paper:Papers for Topics
Location: 554A/Convention Center
Date: Monday, August 2nd, 2010
Time: 9:00 AM