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Abstract Detail



Systematics Section/ASPT

Soto Gomez, Marybel [1], Lam, Vivienne K. Y. [1], Siu, Renée W. I.  [1], Graham, Sean W. [1].

Plastid phylogenomics of Dioscoreales and Pandanales: Reconstructing higher-order relationships and characterizing plastid genome evolution.

Although much progress has been made in understanding the basic phylogenetic structure of the monocots over the past two decades, multiple uncertainties persist in some of the major lineages, including the relationships between and within the orders Dioscoreales and Pandanales. Here we report on our progress in inferring higher-order relationships in these two orders, using whole-plastid data for a genus-level sampling. Dioscoreales comprise ~665 species in three-seven families, and include the economically important yams. Pandanales comprise ~1345 species in five families that display an exceptionally diverse range of habits, including tree-like, herbaceous and climbing taxa. Both orders also include lineages or entire families that have transitioned from a photosynthetic to a non-photosynthetic and mycoheterotrophic life mode. We recovered plastid genomes using genome-survey sequences and de novo assembly from one representative photosynthetic species per genus (corresponding to coding regions for ~83 genes per taxon) and multiple non-photosynthetic taxa. Most taxa are represented by plastid genes sets, but we are also assembling a representative subset of full circular genomes (plastomes), using PCR and Sanger sequencing to bridge contig gaps. We are using these plastomes to characterize genome structural evolution in the orders. To date we have retrieved full plastid gene sets from 14 of ~27 photosynthetic genera in Pandanales, in addition to one plastome from a non-photosynthetic taxon (Triuridaceae). In Dioscoreales we have retrieved plastid gene sets for four of ~10 genera, and plastomes for several non-photosynthetic taxa (Burmanniaceae). Gene order in several photosythetic taxa in the two orders for which we have completed full circles appears to be consistent with other monocots. These data will be integrated with whole-plastid genomes from mycoheterotrophs in the two orders and with monocot-wide plastome data sets. Preliminary analyses provide strong support for moderately supported arrangements from previous studies, such as a sister-group relationship between the two orders, and between Dioscoreaceae and Burmanniaceae in Dioscoreales.


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1 - University of British Columbia, Botany, Room #3529 - 6270 University Boulevard , Vancouver, BC, V6T 1Z4, CAN

Keywords:
Comparative genomics
Dioscoreales-Pandanales
plastid data.

Presentation Type: Oral Paper:Papers for Sections
Session: 34
Location: Evergreen/Grove
Date: Wednesday, July 30th, 2014
Time: 11:00 AM
Number: 34011
Abstract ID:321
Candidate for Awards:None


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