Thale cress is widely used by scientists as a model plant to study a range of topics including genetics, evolution, and plant development. To most people though, it is just a weed that might be found in their garden. It is an annual species, that can complete its life cycle from seed germination through flowering to seed set again in as little as 6 to 8 weeks. It is therefore relatively quick to study sequential generations of the plant.
Biological evolution occurs because initially rare variant forms of organisms become the majority form. All living organisms have a blueprint (genetic code) that determines their form and structure. As organisms grow and reproduce, sometimes this code is not copied perfectly but mistakes arise. Variant form is generated when these mistakes occur – this is known as genetic mutation. Because genetic mutation occurs at low frequency, there are large gaps in our understanding of how it occurs, and in particular of the extent to which the environment affects the process.
Populations (lineages) of the flowering plant Arabidopsis thaliana are being grown here at the Botanic Garden within the Brassicaceae family bed as part of a study being conducted by researchers from the Department of Plant Sciences. Whole-genome DNA sequencing will be used to discover new mutations as they arise in these populations, generation by generation. In the course of this study (and other parallel studies) the Harberd Group will determine the extent to which environmental variables, e.g., temperature, drought, solar radiation, soil chemistry, etc., affect the rates and particular types of mutation that arise in plants growing in nature. Understanding the parameters and patterns with which new mutations arise will in turn enhance our understanding of how evolution generates biological diversity.
More information about the research happening within the Harberd group can be obtained from their webpage.