Abstract Detail

Population Genetics/Genomics

Twyford, Alex [1], Becher, Hannes  [2], Brown, Max [2], Yanqian, Ding [2], Powell, Robyn [3], Pellicer, Jaume [3], Ilia, Leitch [3], Chris, Metherell [4].

Genome gymnastics and problematic polyploidy in eyebrights (Euphrasia, Orobanchaceae).

Polyploidy is pervasive in the evolution of plants and plays an important role in plant adaptation and speciation. However, the intractability of polyploid systems and the challenges of comparative genomics in polyploids hinders our understanding of this key evolutionary process. Here, we investigate the evolutionary history of British diploid and tetraploid eyebrights (Euphrasia), and link polyploid history to parasitism and selfing. In a large-scale survey of natural populations, we show continuous genome size variation within ploidy levels, and clustering by geographic not species in genotyping by sequencing data. These results show the preponderance of local processes such as dispersal limitation and selfing in promoting population divergence. Using whole genome sequencing and a novel k-mer based tool, we show the polyploids are allotetraploids with a consistent level of subgenome divergence between taxa, indicative of a common origin of tetraploid Euphrasia from the same parental progenitors. Finally, we link population differences to host performance in this hemiparasitic plant, and show populations demonstrate some novel host preferences. Overall our results illustrate the complexity of a postglacial species complex, where local process drive fine-scale morphological, genetic and parasitic differences. 

1 - University Of Edinburgh, Institute Of Evolutionary Biology, Ashworth Laboratories, Charlotte Auerbach Road, Edinburgh, EH9 3FL, United Kingdom
2 - University of Edinburgh
3 - Royal Botanic Garden Kew
4 - Botanical Society of Britain and Ireland

British flora.

Presentation Type: Oral Paper
Session: POPGEN3, Population Genetics/Genomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:00 AM
Number: POPGEN3001
Abstract ID:550
Candidate for Awards:Margaret Menzel Award

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