Abstract Detail

Crops and Wild Relatives

Watson, Ray [1], Blackman, Benjamin [2].

Gene expression evolution during sunflower domestication.

Characterizing the developmental and historical context of the genetic changes underlying phenotypic evolution is a key facet in studying the process of adaptation. Domestication offers an ideal case study for adaptive evolution by providing a circumscribed timeline over which many traits dramatically evolve under selection. During the last 5000 years of domestication, the common sunflower, Helianthus annuus, underwent selection for dramatic phenotypic evolution including the loss of seed shattering, seed dormancy and self­incompatibility; an increase in size and weight of fruits and inflorescences; and reduced branching. To reveal changes in transcription potentially contributing to this morphological divergence, we tested for differential gene and isoform expression between wild and domesticated sunflowers by RNA­sequencing. Wild and domesticated plants were grown in controlled conditions, and we sampled 9 tissues across five developmental stages relevant to domestication traits. Paired end reads were assembled with a splice aware aligner and significant differential expression was determined by consensus of several statistical packages. To link expression divergence with signatures of selection during domestication, we examined the intersection of differentially expressed genes with loci highlighted by selective sweep analyses comparing sequence divergence between wild and domesticated sunflowers. By connecting sweeps to developmental stage or tissue specific expression patterns, we advance inferences about which loci contributed to the morphological evolution of specific sunflower domestication traits. Our candidate domestication genes will be targeted for ancient DNA sequencing from archeological samples to build a timeline of adaptive evolution during domestication and study the rate and scope of sunflower evolution.

1 - University of California, Berkeley, Biology, 54 Mulford, Berkeley, California, 94720, USA
2 - University Of California, Berkeley, Plant And Microbial Biology, 111 Koshland Hall #3102, Berkeley, CA, 94720, United States

Differential Expression Analysis

Presentation Type: Oral Paper
Abstract ID:451
Candidate for Awards:None

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