Research interests

     Research in our lab tackles major questions in plant ecological and evolutionary genetics, including: What are the traits/phenotypes and genes that allow plants to adapt (survive and reproduce) to local environmental conditions? Does adaptation to one environment result in a fitness cost in other environments? What are the constraints on adaptation and persistence in the face of environmental change? These longstanding questions are directly relevant to understanding biological diversification and species range limits and are additionally important because of the threats of climate change and increasing climatic variability on biodiversity. These questions are also relevant to agriculture where high yield is directly tied to adaptation. Understanding the genetic basis of variation in yield across environments is important for improving resilience to climatic variation, and knowledge of the mechanisms and constraints on adaptation in nature may inform the paths of least resistance for crop improvement efforts. Reseach of these questions in the lab has two main foci:


Genetic basis of local adaptation and fitness trade-offs across environments


    Our research uses integrative approaches to understand how naturally occurring sequence polymorphisms shape molecular, physiological, and organismal phenotypes, and ultimately how these phenotypes affect survival and reproduction in contrasting natural environments. We combines genetics and genomics, growth chamber experiments simulating natural conditions based on field data, phenotyping, and classical ecological field experiments.


     We areparticularly interested in the genetic basis of cold-acclimated freezing tolerance. This is an important and timely topic because plastic responses to temperature cues that condition freezing tolerance are ubiquitous in plants across the temperate zones. These responses are likely to incur an energetic cost and decrease fitness in the absence of severe freezing, as might occur with climate change. Cold-acclimated freezing tolerance also represents the best candidate adaptive trait involved in local adaptation and fitness trade-offs across environments in the study system described above, where large-effect freezing tolerance quantitative trait loci (QTL) were found to co-occur in genomic regions underlying genetic trade-offs across environments


Genetic basis of heterosis and constraints on adaptation


Despite many remarkable examples of organismal adaptation, the potential for further adaptation to changing conditions may be limited. These constraints arise because limited population sizes, spatial isolation, and inbreeding are all common in plants, which limits the amount of beneficial genetic variation available and increases the chance fixation of alleles with negative (deleterious) effects on survival and reproduction. Heterosis, or the increased vigor of hybrids compared to parental lines, has long been important in agriculture. We use heterosis as a tool to infer patterns of fixed deleterious variation within natural populations. So far we have examined heterosis in three different contexts. 1) Extension of the genetic resources, tools, and expertise developed for the study of adaptation in Arabidopsis to investigate the genetic basis of heterorisis and how the magnitude of heterosis varies across environments. 2) Investigating the role of heterosis in maintaining outcrossing in species that exhibit a floral heteromorphism where individual plants produce both outcrossing and self-fertilizing flowers. 3) Using heterosis to evaluate restoration strategies for remnant populations of rare species.