• Evolutionary Biology 
     Zanis Lab 
      b o t a n y   a n d   p l a n t   p a t h o l o g y
  p u r d u e   u n i v e r s i t y

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    Research

    Overview: We are interested in multiple aspects and scales of evolutionary biology. Our first long-term interest is to identify evolutionary processes that shape diversity in genetic pathways. A second long-term focus is to determine the genetic structure of ecological communities. Some of our projects include:

    agamous Evolution of Developmental Genetic Pathways (Evo-Devo): Gene and genome duplications together with mutation accumulation are processes that play an important role in the diversification of genetic pathways. What is the frequency with which gene duplications occur and what are the evolutionary changes that occur in duplicate genes - especially over long evolutionary time scales? To address this and similar questions, we are investigating the rates of changes in MADS-box genes. MADS-box genes represent a class of transcription factors that play an important role in regulating plant development. We use phylogenetic inferences to understand the origin of gene duplicates as well as the nucleotide substitutions that have occurred in coding DNA and “non-coding” putative cis-regulatory elements across angiosperms. We are testing the functional changes associated with gene duplications using both grass systems and Arabidopsis.

    leersia Evolutionary and Ecological Diversification of North American Wild Rice (Zizania sp) and Rice Cutgrass ( Leersia sp): Population level extinction (extirpation) and subsequent loss of genetic diversity are major factors in the overall decline of global biodiversity and ecosystem structure. The complexity of long-term population persistence involves the interaction of genetic variation and phenotypic response to environmental variables. We are examining the evolutionary genetics of North American Wild Rice, Zizania, and Rice Cutgrass, Leersia, species across their geographic range. Zizania and Leersia are closely related to domesticated rice, Oryza sp. We are investigating multiple aspects of Zizania sp. and Leersia sp. biology including speciation, evo-devo and eco-devo, evolutionary ecology of reproductive strategies, adaptation to abiotic stressors, and hybridization barries. One area we are espescially excited about is understanding molecular evolutionary dynamics of genes that regulate ecologically important morphological and physiological traits. We are conducting experiments, greenhouse and field, that test for relationships between patterns of molecular evolution and ecological variables.

    community_genetics Evolutionary and Ecological Genomics of Aquatic Communities: The goal of this project is to examine patterns of genetic diversity across species at the community scale. This research is evaluating the spatial and temporal distribution of genetic diversity across interacting aquatic plant and insect species that span 400 million years of evolutionary diversification. Although a number of conceptual models exist that explain how interacting species may co-evolve, much remains to be learned about which concpetual model best fits "natural" communitites. We have identified a set of insect and plant species with interesting and varied ecological relationships, providing an opportunity to address a number of questions about the patterns and consequences of genetic variation at the community scale. For example, what are the rates of gene flow between aquatic communities across taxonomic scales. Levels of gene flow are important for shaping local adaptation and evolution of populations. In order to address this question as well as others, we are using species of aquatic plants and aquatic insects as well as a combination of coalescent and phylogenetic approaches and second generation sequencing.

    Computational and Theory Based Research: Phylogenetic trees are a widely used as statistical estimates of evolutionary relationships in the biological sciences. However, much work remains in understanding the powers and pitfalls in applying phylogenetic methodologies to diverse data sets. We have several projects that involve the use of phylogenetics towards understanding and linking genome evolution to biodiversity:

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