Willis, John H , Wu, Carrie A. .
Ecological genetics of drought adaptation in sympatric Mimulus.
Local adaptation has been widely documented in plants, but far less is known about the traits conferring this adaptation to specific environments. Variation in spatial and seasonal soil water availability is a fundamental determinant of plant distributions, and likely has been an important selective factor in shaping the evolution of numerous species complexes. Even within species, plants have evolved several strategies to cope with water limitation, which involve morphological, physiological, and life history traits. Here we use a quantitative trait locus (QTL) mapping approach to examine the genetic architecture of putatively adaptive drought response traits that differ between Mimulus guttatus and M. nasutus, two closely related flowering plants with contrasting mating systems. We constructed a linkage map from a large F2 mapping population (N=480) with ~200 EST markers, that has greater coverage than previous collinear maps in Mimulus. Analyses have identified several regions with strong effects on water-use efficiency (d13C) and flowering time, including at least one that colocalizes for the two traits. The presence of genomic regions containing QTL with effects on both flowering time and d13C suggests a potential pleiotropic relationship that contributes to differences in drought response strategies; however, polygenic control of individual traits may allow these traits to evolve independently from one another.
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1 - Duke University, Department of Biology, Box 90338, Durham, NC, 27708, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Huron/Hilton
Date: Monday, July 9th, 2007
Time: 4:15 PM