Evolutionary Developmental Biology (Evo-Devo)
Glenwinkel, Lori , Malcomber, Simon .
Developmental gene evolution of SEPALLATA 3 (SEP3) genes in graminoid Poales.
The evolution of the grass floret and spikelet has fascinated botanists for centuries. During the evolution of graminoid Poales, several changes occurred in the organization of the canonical monocot flower to produce the floret and spikelets that characterize the bulk of grass species. SEPALLATA3 (SEP3) genes function as co-factors with other floral organ identity genes and are hypothesized to have played a role in the evolution of grass floral structure. Unlike other monocots, grasses have two SEP3 copies (SEP3A and SEP3B), but it is unknown when the duplication event that produced these two lineages occurred. Bayesian phylogenetic analyses using newly isolated Pharus (the earliest diverging grass with a true grass spikelet), Joinvillea (Joinvilleaceae) and Thamnochortus (Restionaceae) sequences now support a well-supported grass SEP3A+SEP3B clade that is sister to the Joinvillea SEP3 sequence. This phylogenetic estimate points to the SEP3A/SEP3B duplication event near the base of the grass family and, coupled with positions of the rice SEP3A and SEP3B genes in duplicated parts of the genome, supports the hypothesis that the genes are products of the grass whole genome duplication event. RNA in situ hybridization and molecular evolutionary analyses will be used to test for evidence of neo- and/or sub-functionalization following the SEP3 duplication event and how these genes, along with other SEP and floral organ identity genes, have contributed to the origin of the grass spikelet and floret. Exploring duplicate gene evolution using SEP3 genes will provide insights into the origin of unique grass inflorescence structures, plus further elucidate the developmental role of SEP3 genes in monocots.
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1 - California State University Long Beach, Biology, 1250 Bellflower Blvd., Long Beach, CA, 90840, United States
2 - California State University, Long Beach, Biological Sciences, 1250 Bellflower Blvd, Long Beach, CA, 90840, United States
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM