[Plantsci] Itinerary spots for Dr. Aaron Liston

[Lambert, Georgina M - (glambert)]

On Behalf of Shelley McMahon:



Dr. Aaron Liston, Oregon State University, will be giving the departmental seminar in Plant Sciences next week, Tues Oct 27, 4pm, Marley 230.



Dr. Liston's presentation will be about using comparative genomics to unravel the tortured history of polyploidy in Fragaria (please see abstract, below). His research applies molecular and genomic technologies to important questions of evolution and systematics, and his projects include pines, legumes, milkweeds, and strawberries. For more information and a complete list of his publications, please see http://bpp.oregonstate.edu/liston.



If you are interested in meeting with him Tues Oct 27, please contact Shelley McMahon (mcmahonm at email.arizona.edu<mailto:mcmahonm at email.arizona.edu>).





Seminar abstract:



Whole-genome duplications are radical evolutionary events that have

driven speciation and adaptation in many taxa. Higher-order polyploids

have complex histories often including interspecific hybridization and

dynamic genomic changes. This chromosomal reshuffling is poorly

understood for most polyploid species, despite their evolutionary and

agricultural importance, due to the challenge of distinguishing

homologous sequences from each other. I will present our results from

dense linkage maps generated with targeted sequence capture to improve

the diploid strawberry (Fragaria vesca) reference genome and to

disentangle the subgenomes of the wild octoploid progenitors of

cultivated strawberry, F. virginiana and F. chiloensis. In contrast to a

widely accepted model, we find that one of the four subgenomes

originates with the diploid cytoplasm donor F. vesca, one with the

diploid F. iinumae, and two with an unknown ancestor close to F.

iinumae. Extensive unidirectional introgression has converted the F.

iinumae-like subgenomes to be more F. vesca-like, but never the reverse,

due either to homoploid hybridization in the F. iinumae-like diploid

ancestors or else strong selection spreading F. vesca-like sequence

among subgenomes via homeologous exchange. In addition, divergence

between homeologous chromosomes has been substantially augmented by

interchromosomal rearrangements. Our phylogenetic approach reveals novel

aspects of the complicated web of genetic exchanges that occur during

polyploid evolution and suggests a path forward for unraveling other

agriculturally and ecologically important polyploid genomes.

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