Litt, Amy , Lalchan, Rebecca , Nowogrodzki, Anna .
The genetic basis of divergence in flowering time in response to climate change in wild populations of Brassica rapa.
Populations of the diploid annual plant Brassica rapa (wild mustard) in California have been shown to rapidly evolve earlier flowering time following a natural drought. The changes in flowering time were shown to have a genetic basis, however, the nature of the genetic underpinnings of this evolutionary change is not known: which genes were involved and the extent to which changes in gene sequence, expression or epigenetic regulation played a role. Flowering time in the closely related Arabidopsis thaliana has been well characterized genetically, but few studies have examined the evolution of flowering time genes over time and in response to changes in climate in natural populations. Using population genetic analyses and a candidate gene approach, we are integrating the known information on flowering time genetics of Arabidopsis with the demonstrated natural evolutionary change in flowering time in B. rapa to characterize the genetic basis of this evolutionary response to climate change in natural plant populations. Microsatellite-based population genetic analyses assess the extent of gene flow between these populations as flowering time diverges and converges over the course of several seasons of drier and wetter climatic conditions in California. These analyses examine the consequences of evolutionary changes in flowering time for gene flow and genetic structure in natural populations. In addition, we are evaluating gene expression at candidate loci to identify differences in gene activity correlated with the observed differences in flowering time. B. rapa possesses four genes related to the Arabidopsis flowering time integrator FLC, and these loci have been shown to have an additive effect on regulating flowering time. Thus our preliminary analyses focus on quantitative changes in expression of these closely related paralogs in two populations with divergent flowering times.
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1 - The New York Botanical Garden, 200th St and Southern Boulevard, Bronx, NY, 10458-5126, USA
2 - Fordham University, Department of Biological Sciences, Larkin Hall, 441 East Fordham Rd, Bronx, NY, 10458, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Monday, July 27th, 2009
Time: 2:15 PM