Research Fellows Directory
Dr Angela Hay
University of Oxford
Counting to four: genetic control of petal number.
Biologists are fascinated by the diversity of living forms and how they evolved and we want to understand exactly what makes species look different. The model species thale cress has a typical crucifer flower, with four petals forming a cross, while hairy bittercress is unusual because petal number varies from zero to four. We want to know which genes control petal number and how these were altered during evolution to vary petal number between thale and hairy bittercress. We chose these two species because they are easy to work with and are closely related. This means that they share similar DNA, which makes it easier to identify the genetic differences that distinguish their flowers. I worked out that differences in the DNA sequence of a gene called APETALA1 (AP1) contribute to the difference in petal number between thale cress and hairy bittercress. By transferring the AP1 gene between the two cresses I could convert the petal number of hairy bittercress flowers to 4 and thale cress to 0. What I find really exciting about this discovery is that introducing just 9 DNA bases from the hairy bittercress AP1 gene into the thale cress AP1 gene was sufficient to cause petal loss in thale cress.
Explosive pod shatter: a biomechanical innovation.
Adaptations for dispersal are ubiquitous in nature because of the fitness advantages offered to plants and animals. Explosive pod shatter in hairy bittercress is a ballistic seed dispersal mechanism that allows this invasive weed to successfully colonise new habitats. With the aid of laser beams and high-speed cameras filming at 15,000 frames per second, we have measured seeds speeding at over 40 km/hr out of hairy bittercress fruits. By working with engineers and mathematicians we have recently devised mechanical models of explosive pod shatter. This allows us to explore how evolution tunes the development and physics of a complex biological system to send seeds speeding.
Interests and expertise (Subject groups)