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Abstract Detail

The evolutionary importance of polyploidy

McKain, Michael [1], Layton, Daniel J. [2], Pasquet, Rémy [3], Schnable, James C. [4], Estep, Matt C. [5], Malcomber, Simon T. [6], Vela Diaz, Dilys [7], Zhong, Jinshun [8], Brutnell, Thomas P. [2], Kellogg, Elizabeth [9].

Dissecting the Shared Allopolyploid History of Zea and Tripsacum.

Polyploidy, and in particular allopolyploidy, plays a major role in shaping plant genomes. The grasses are well-known for multiple instances of polyploidy and have been a focus of many studies looking at polyploidy and genome evolution. A recent study in the tribe Andropogoneae demonstrated that one third of species in the clade have been produced by allopolyploidy, with most of these events being independent of each other. The majority of events have occurred in the last 5 million years, but the Zea-Tripsacum whole genome duplication (WGD) event stands out, as it is the oldest, occurring between 18 and 12 million years ago. This allopolyploid event has been known for almost a century, though its exact nature has not been understood. Despite the rich genomic resources available in Andropogoneae, genomic sampling of the phylogenetic diversity has been too sparse to elucidate the evolutionary history of the Zea-Tripsacum WGD event. Here, we extend that sampling by first providing a well-resolved whole chloroplast phylogeny of more than 80 species of the Andropogoneae as an evolutionary framework. This has allowed us to identify the maternal parent of previously identified allopolyploids and to show that the maternal lineage of the Zea-Tripsacum WGD event has no extant taxa other than Zea and Tripsacum. We then sequenced transcriptomes for 22 species, including five Tripsacum species, and combined them with available Andropogoneae genomes (Zea and Sorghum) and transcriptomes from Phytozome and GenBank. With a phylogenomic approach, we demonstrate that there exists at least one extant parental lineage of the Zea-Tripsacum polyploid event, a relatively obscure group native to Africa. This lineage provides an invaluable resource for understanding the effects of the Zea-Tripsacum polyploidy event on the evolution of the maize genome. We assign syntenic regions of the maize genome to true subgenomes based on their evolutionary history. We then test the dominance of these subgenomes using available expression data.

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1 - Donald Danforth Plant Science Center, Plant Biology, 975 N. Warson Rd., St. Louis, MO, 63132, USA
2 - Donald Danforth Plant Science Center, 975 N Warson, St Louis, MO, 63132, United States
3 - Unité de Recherche Institut de Recherche pour le Développement, Laboratoire Évolution, Génomes et Spéciation, 91198, Gif-sur-Yvette, France
4 - University of Nebraska, Agronomy and Horticulture, Bead E207, Lincoln, NE, 68583, USA
5 - Appalachian State University, Department of Plant Biology, Rankin North 213, Boone, NC, 28608
6 - National Science Foundation, Division of Environmental Biology, Arlington, VA, 22230
7 - Washington University in St. Louis, Department of Biology, Campus Box 1137, St. Louis, MO, 63130
8 - Department Of Biology, 323 Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05401, USA
9 - Donald Danforth Plant Science Center, Department Of Biology, 975 North Warson Road, St. Louis, MO, 63132, USA


Presentation Type: Symposium Presentation
Session: SY19
Location: Salon 4/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 2:45 PM
Number: SY19004
Abstract ID:1082
Candidate for Awards:None

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