Ecological genomics of developmental timing

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One of plant biology's major goals is to describe how variation in genes at the sequence level creates phenotypic variation. One area of rapid progress has been describing how variation at regulatory genes in the genetic model plant, A. thaliana, affects variation in a key developmental trait, the transition from vegetative to reproductive growth. Despite this progress, it is unclear how much of this variation is adaptive.   I will investigate whether clines in development timing and developmental sensitivity to cold (i.e., relationships between these traits and geographic factors) have evolved in invasive populations of A. thaliana, parallel to clines I detected in European samples. Parallel clines in invasives would be strong evidence that the variation in developmental timing and developmental sensitivity in A. thaliana is adaptive. I will also investigate if two major developmental genes, FRI and FLC, are variable in N. America and lead to geographic variation in these traits and fitness.   My specific aims are to: (1) Collect a set of North American A. thaliana ecotypes over a broad geographic range, and genotype them for a large set of SNP markers to assess population genetic structure and linkage disequilibrium, (2) Use these SNP data for N. American A. thaliana populations and published SNP data on Eurasian samples to place N. American invasives into a global phylogeographic context, (3) Test whether a parallel cline in developmental timing has evolved among N. American accessions, and if  it depends on FRI functionality, (4) Test for parallel geographic divergence in developmental sensitivity to cold in N. American accessions, (5) Plant lines variable for both FRI and FLC into field sites, and measure natural changes in allele frequency at these loci. The proposed work will support training several HQP and advance our knowledge of developmental timing, plant reproduction, and the genetics of invasive species because it evaluates the roles of molecular genetic and environmental variation in shaping complex traits, and tests for genetic and evolutionary parallelism.