Byers, Diane .
Natural variation and its genetic basis in Arabidopsis thaliana in response to soil nutrients.
THE evolutionary process that leads to adaptation can be viewed as a dynamic interplay between selection and the genetic architecture of fitness traits. Over time selection can erode genetic diversity, which can lead to local adaptation. However, selection and genetic architecture of traits as expressed in contrasting environments can constrain evolutionary response and have been proposed to facilitate maintenance of genetic variation. We have recently started a series of experiments using wild populations of Arabidopsis thaliana to experimentally examine this dynamic between selection in heterogeneous soil nutrient environments and genetic characteristics of the population. First, I report on the results of the first of these studies where plants from 11 populations from Michigan were grown in low or high soil nutrients. Second, I report on the QTL analysis of recombinant inbred lines (ColxLer) that were grown in different soil nutrients representing the natural variation to gain further insight into the genetic basis of the phenotypic variation among environments. Traits throughout the life cycle representing size, life history and fitness were measured in both studies. The nutrient environment significantly affected most of the traits in the studies. The natural populations, as well as the genetic lines within each population, also significantly contributed to the variation for many of the traits. In a more limited set of traits, a significant expression of phenotypic plasticity was found. A limited but significant influence of selection history in the natural population was found in reproductive traits. Results from the QTL analysis indicated that particular genes (QTL) are only expressed in particular soil conditions. Together these results indicate selection history may structure the genetic architecture of a population. This effect of the selection history on genetic architecture has the potential to limit or facilitate the ability to adapt to different or changing environments.
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1 - Illinois State University, Department of Biological Sciences, Campus Box 4120, Normal, Illinois, 61790-4120, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, August 1st, 2006
Time: 10:30 AM