Genetic basis for phenotypic evolution
My group exploits the extensive experimental tools developed in C. hirsuta (see Tsiantis group) to ask how variation in the organisation of gene networks between C. hirsuta and A. thaliana drives the evolution of fruit and floral structures. Our reasons for focusing on these morphologies are four-fold: first, these are rapidly evolving traits that can be compared between related but reproductively isolated species; second, the direction of evolutionary change in these morphologies is known, third, these traits likely have adaptive value for pollination and seed dispersal strategies, and finally, understanding these processes has potential translational value for Brassica crop improvement.
Petal number variation
Inter- and intraspecific variation
Petal number is constant in A. thaliana but variable in C. hirsuta. We find petal number variation not only between these two species but also within C. hirsuta. We capitalize on this inter- and intraspecific variation to address fundamental questions about evolutionary change:
- Are single gene changes sufficient to explain species-specific form?
- What are the precise genetic changes?
- How are genetic changes translated into phenotypic differences?
- Do inter- and intraspecific variation have the same genetic basis?
Explosive pod shatter
Genetics and mechanics of development
Explosive pod shatter in C. hirsuta is a ballistic seed dispersal mechanism that transfers stored mechanical energy from fruit tissues to the seeds as they are launched such that seeds disperse over a 2 m radius away from the mother plant. In comparison, A. thaliana pod shatter is non-explosive. We aim to understand how differences in fruit morphology evolved to provide these two species with dramatically different seed dispersal strategies.
We are taking a combined biological and computational approach, in collaboration with the Smith group, to conceptualize how the interplay of genetic and mechanical regulation in the developing fruit is translated into explosive pod shatter. The outcome of this work will be predictive models of fruit development that capture the diverse seed dispersal strategies of C. hirsuta and A. thaliana in a quantitative fashion.