Young Wha Lee

I am interested in the genetic basis of complex traits and their evolution.  My thesis project addresses the genetic architecture of standing variation and the evolutionary mechanisms that maintain that variation.  My study organism is the Mimulus guttatus species complex, which consists of of the bee-pollinated hermaphroditic guttatus with large showy flowers, and a number of selfing species thought to be derived from a guttatus-like ancestor. Abundant variation in flower size is observed at multiple levels -  at the extremes, the selfer M. nasutus has very small cleistogamous flowers compared to M. guttatus, and guttatus populations adapted to coastal conditions have flower sizes 1.9X larger than alpine meadow populations.  We have made evident the extant of intra-population variation by artificial divergent selection for flower size on a population collected from Iron Mountain, OR.  This experiment, conducted by our collaborator John Kelly (U Kansas), produced in the extremes of the distribution almost the whole range of variation observed within the species complex.  We are currently mapping QTLs that affect flower size and fertility component variation within Iron Mountain.  A finemapping/positional cloning project is also in progress to isolate the genes underlying the QTLs, in order to 1) isolate QTN by association mapping and 2)apply molecular population genetic tests that can detect evidence of past selective processes.  Finally, NILs and RILs will be used in a series of controlled experiments in the phytotron and field to test balancing selection hypotheses (antagonistic pleiotropy, gene-environment interaction) on a per-locus basis.

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