There is extensive natural variation in vernalization requirement and response in Arabidopsis thaliana accessions collected from different regions of the world.
The Dean lab are investigating the molecular basis of this variation and its contribution to adaptation of Arabidopsis.
They have characterised both worldwide and regional (Swedish) Arabidopsis accessions and found allelic variation at FLC is a significant contributor to the natural variation in vernalization response. Detailed analysis of a Northern Swedish accession has mapped polymorphism in non-coding domains of FLC that determine a need for longer winters. The polymorphisms attenuate the Polycomb-mediated chromatin silencing so linking natural variation and mechanistic analysis. They are investigating how these polymorphisms influence the epigenetic silencing of FLC.
Genetic architecture of FLC in worldwide Arabidopsis accessions has identified a number of functionally distinct alleles. Association of these alleles with phenotypic variation is ongoing.
The Dean lab are exploring their ecological significance through field experiments in Sweden.