Research in Lisa Dorn's Lab

Dr. Lisa Dorn is interested in the genetic basis and evolution of important age- and stage-related transitions in plants, otherwise known as life history traits, using the model plant species Arabidopsis thaliana. The evolution of life history traits is especially interesting because these traits are closely associated with vigor and reproductive ability, the targets of natural selection. Given current concerns about climate change, Dr. Dorn has concentrated on the genetic control of plant responses to the environment via changes in their life history. These traits tend to be influenced by many genes or quantitative trait loci (QTL), some with very small effects. Her work combines molecular techniques with statistical genetics methods to identify the QTL involved in the response to environment, especially those that contribute to plant adaptation to novel environments such as those they might experience when colonizing a new site or in the event that climates drastically alter their present site. Toward that end, Dr. Dorn has developed a set of highly variable genetic strains (recombinant inbred lines) that can be used to map the locations on the chromosomes of the genes most responsible for the response to environment. She is currently analyzing data from a very large experiment, funded by the National Science Foundation and completed in 2003, that used these lines to test maternal effects on germination responses in different climates and how climate and maternal environments change the strength and direction of natural selection on the entire life history, not just individual stages. Dr. Dorn also develops genomic tools in collaboration with others to identify, among the large complement of genes, the specific genes that may affect a plant’s ability to respond to climate change and maternal environments. In collaboration with Kathleen Donohue (Harvard University), Dr. Dorn has developed a map of microsatellite and CAPs markers for her recombinant inbred lines. In collaboration with Cynthia Weinig (U. of Minnesota) and Julin Maloof (UC Davis), Dr. Dorn is developing a map of single nucleotide polymorphisms for these same lines, to be completed by October 2004.

All of these tools are ready-made for exploitation by undergraduates to identify genes that influence their favorite trait’s response to specific environmental factors they find interesting. Because the response to environment is also a question of variable gene expression, Dr. Dorn is designing experiments using commercially developed gene microarrays that have become available since the successful completion of the Arabidopsis Genome Sequence Project. These microarrays will be used to monitor changes in both global and tissue-specific gene expression in different environments, both reasonable projects for undergraduate involvement. Even before completing the mapping of environmentally-sensitive genes, Dr. Dorn is manipulating her recombinant inbred lines in a series of crosses that will result in a set of genetic lines that in combination with microarray technology can accomplish three goals: (a) distinguish between the expression of genes in the maternal tissue of a seed vs. the embryo, (b) elucidate interactions among genes that may indicate regulatory mechanisms influencing tissue-specific gene expression responses to environment, and (c) winnow the number of genes for further study to a few candidates. Additional projects that undergraduates will work on include a long-term experiment where the wide range of recombinant inbred genetic strains would be planted in a field experiment and monitored for changes in gene frequency over time.