Evolutionary genetics and plant reproductive biology
My research seeks to understand fundamental processes in plant reproduction and evolution using genetics and genomics. Current research is focused on studying the interacting forces of mating system, interspecific hybridization, and polyploidy in the evolution of taxonomically ‘difficult’ genera, in particular Senecio (ragworts, Asteraceae) and Sorbus (whitebeams, rowans and wild service trees, Rosaceae).
The genomic basis of adaptation and speciation in the genus Senecio (Asteraceae)
Speciation events in Senecio have occurred relatively recently and involve examples of ecological speciation (sister species Senecio aethnensis and S. chrysanthemifolius) and hybrid speciation, both homoploid (S. squalidus) and allopolyploid (S. cambrensis). This project seeks to understand the genomic basis of speciation in the closely related species S. aethnensis and S. chrysanthemifolius, which diverged on Mt Etna, Sicily ~300 thousand years ago, and their homoploid hybrid, S. squalidus (Oxford ragwort), which evolved in allopatry in the UK following its introduction via the Oxford Botanic Garden ~300 years ago. The project is in collaboration with Dmitry Filatov (Oxford), Tom Batstone and Gary Barker (Bristol), Richard Abbott (St Andrews), Adrian Brennan (Durham) and Matthew Hegarty (IBERS, Aberystwyth). Current work is focused on analysing draft genome sequences, transcriptomes, and microRNA profiles for all three Senecio species to determine the relative importance of coding sequence changes vs non-coding regulatory sequence changes in their genetic divergence and adaptation to their distinct habitats.
The molecular basis of sporophytic self-incompatibility (SSI) in the Asteraceae
Another aspect of the Senecio genome project involves bioinformatic analysis of a genomic region containing candidate genes for self-incompatibility - the S-locus. The identification of a putative S-locus in Senecio (in collaboration with Tom Batstone, Bristol), and in Cichorium (chicory, in collaboration with Theo Hendriks and Marie-Christine Quillet) offers an opportunity to elucidate the molecular basis of SI in the Asteraceae.
Genetic divergence, mating systems, and ongoing evolution in the genus Sorbus (Rosaceae)
This project uses molecular markers (cpDNA, microsatellites and dd-RAD) to understand the evolutionary relationships between UK and European Sorbus species. Work to date has shown that Sorbus diversification in the Avon Gorge, Bristol is ongoing and is driven by hybridization, polyploidy, and facultative apomixis. These findings have influenced conservation management strategy for Sorbus in the Avon Gorge – a world ‘hotspot’ for Sorbus diversity. Current research in collaboration with Mike Fay (RBG Kew) seeks to determine the origin of Sorbus porrigentiformis, which has been central to the origin of new Sorbus taxa in the UK via hybridization.