There has been intense recent interest in the geneticmechanisms by which plant and animal populations respond tonatural selection. Theories of population genetics suggest thatfunctional interactions between different genes of an organismmay result in adaptations not predicted from studies of thedifferent genes independently. These kinds of gene interactionshave been well.documented in some laboratory animals anddomesticated plants, but have never been evaluated in naturalpopulations of animals or plants. The reason for this is thatgene interactions are difficult to document in diploid organismswithout extremely complicated, expensive, and time.consumingbreeding programs. This proposal initiates a project to measure interactionsbetween different genes by concentrating on an organism whosehaploid genetic system simplifies the analyses considerably. Gene interactions that determine the degree of tolerance to heavymetals will be evaluated because metal tolerance is clearlyadaptive to plants in habitats contaminated at toxic levels. This research will significantly further our understanding of thegenetic mechanisms of adaptation and evolutionary change. Themethods of genetic analysis developed for this study will beapplicable to other organisms as well.
