We deploy a diversity of approaches to contribute to our understanding of plant evolution, (and evolution in general). Here are the main approaches being utilized. If you want to know more, please don't hesitate to contact us.

Systematics/Phylogenetics: The lab has used molecular phylogenetics to address a diversity of problems: morphological evolution, the evolution of plant-pollinator interactions, biogeography, rates of evolution, key innovations, hybridization, ring species, and species limits. David Baum has broad experience in systematic theory and enjoys working with students to apply phylogenetic approaches to novel biological problems. Current projects include analysis of the infraspecific genealogy of Arabidopsis thaliana based on whole genome resequencing data and developing a targeted-sequence capture platform for Adansonia (and other bombacoids) to use for high-throughput analysis of low-level genealogy and species delimitation. Alison Scott is also using sequence-capture and next-gen sequencing and applying it to reconstruct the evolutionary history of redwoods.

Conceptual issues and philosophy of biology: Understanding evolutionary phenomena can be aided by thinking clearly about terms and the concepts they are intended to capture. These issues are frequently discussed and of great issues to the lab group. The current focus is on developing a new concept of homology based on developmental causation and a formalism for representing the relationship between genotype and phenotype. More information on this approach is described in this publication.

Theory and statistical methods: We have ongoing collaborations with statisticians to develop new methods related to low- level phylogenetics. The aim is to use multilocus sequence data to estimate the distribution of gene genealogies that coexist within a set of genomes. We can then extract insights into the evolutionary forces (incomplete lineage sorting, introgression, etc.) that have shaped that distribution. One prominent product of this collaboration is the program BUCKy, which conducts Bayesian concordance analysis. We are improving the underlying model to better distinguish discordance due to incomplete lineage sorting along the branches of a strictly divergent population tree from other causes of discordance, such as introgression. Also, we are exploring ways to make the algorithm more efficient for large data sets and to allow for more direct assessment of reticulate histories. This work is a collaboration with Cécile Ané and Bret Larget.

Candidate gene Evolutionary Developmental Genetics (Evo-Devo): A long-standing interest in the lab is trying to identify genes underlying species differences. We have used developmental genetic knowledge from model species to guide studies of several different traits in different plant groups. In many cases, projects started in my lab are still being pursued by former graduate students or post-docs in their own independent labs. Examples of phenotypes studied are: inflorescence architecture, trichome shape, flower color, petal spot position, dioecy, and stamen number. The approaches used have included electron micrography, in situ hybridization, immunolocalization, qPCR, analyses of molecular evolution, and plant transformation. Currently, Abigail Mazie is studying the evolution of cell shape by studying candidate genes (BLT and STI) for the origin of stellate trichomes in Physaria (Brassicaceae), and C. R. Pulikesi is studying the role of LFY and TFL1 in the evolution of rosette-flowering in Leavenworthia.

Origin of life: In a collaboration with several colleagues in the Department of Chemistry and the Wisconsin Institute for Discovery, we areworking on a project that explores the potential for deploying selection in a lab setting to drive the de novo appearance of life-like chemical consortia.

Origin of eukaryotes: In collaboration with Buzz Baum (University College, London) we are developing improved models for the origin of eukaryotic cell structure.

 

 
 


 

 

 

 

 

 

 

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