OOS 12-3 - Using genomic approaches to study environmental adaptation in Mimulus

Tuesday, August 9, 2011: 8:40 AM
15, Austin Convention Center
John Willis, Forestry, Michigan State University, East Lansing

A major challenge to ecologists and evolutionary biologists is to understand how populations change genetically as they adapt to changing abiotic and biotic environments.  Do populations generally respond to environmental challenges by evolving at many genes throughout the genome, each of which has a small effect on fitness, or can populations adapt via changes at a handful of genes?  And how, mechanistically, do these genetic changes actually increase an organism’s performance and fitness in the new environments?  Traditionally such questions have been almost impossible to answer in most species.  Now however, with the development of powerful and affordable DNA sequencing technologies, we are beginning to be able to make rapid progress in understanding the molecular genetic basis of ecological adaptations.  We are using this new technology to study differences in habitat adaptation among populations of the wildflower Mimulus guttatus, a common species in western North America that until recently had no genetic or genomic resources.  We are using several different approaches to locate in the genome the key genes involved in the plants’ adaptations to extreme edaphic environments, such as serpentine soils, copper mine tailings, and granite outcrops.


Using several new and powerful genome mapping methods, we have discovered regions of the genome that affect traits that are adaptive in these extreme environments, including rapid flowering, altered leaf shape, and the ability to grow roots in serpentine or copper soils.  We have also used whole genome sequencing and analysis of populations growing on and off the copper mine tailings to discover genes that have contributed to the adaptation to copper soil environments.

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