*EASTBIO* The importance of genome duplication in the origin of novel plant diversity

Supervisors: Alex Twyford ([Email Address Removed]), Catherine Kidner ([Email Address Removed])

Related species often show differences in genome structure, with whole genome duplication (polyploidy) representing one of the most dramatic forms of genomic variation. Whole genome duplication has long interested evolutionary biologists, as it may prevent cross-mating between diverging taxa, and thus promote speciation. However, recent genomic analyses have cast doubt on this assumption, as ongoing gene flow has been detected between polyploids and their diploid relatives. Additional genomic studies are required to test whether polyploidy can cause instantaneous and complete reproductive isolation, and thus be a mechanism underlying sympatric speciation.
This project will investigate the importance of polyploidy in the evolution of the plant genus Euphrasia (eyebrights). This genus includes c. 20 species in the UK, with diploids and tetraploids that commonly co-occur and are thought to occasionally hybridize. We have recently sequenced the complete genome of the diploid, and shown that diploids and tetraploids are highly genetically divergent. We have also located a site in South Wales where diploids and tetraploids co-occur. These resources and observations provide the background for further studies investigating polyploidy and hybridization in this group.
This project will use draft genome sequences, and generate new population genomic data and field observations, in order to:
1. Understand genomic differences between diploids and tetraploids.
2. Observe the extent of localised gene flow in a diploid-tetraploid hybrid zone.
3. Look for evidence of historical gene flow between diploids and tetraploids across the UK.
Overall, this project represents an exciting example of where cutting-edge genomic tools and classic field observations can shed light on an important yet poorly understood evolutionary processes. This project will offer training in genomic analysis, and include fieldwork in South Wales and other areas of the United Kingdom.