Molecular Drivers of Evolutionary Transitions

Description:

In order to make sense of biological diversity, many studies compare traits between modern-day species in an attempt to reconstruct the evolutionary process. In addition to shedding light on the astounding variety of life, this method has given way to several iconic questions that have persisted since Darwin’s time. Over the past ~15 years, however, advancements in experimental systems have allowed researchers to test classical evolutionary problems in unprecedented ways: by examining diverse molecules as they change over time and dissecting the drivers of historical phenotypic transitions. This course will present several cases from the literature that identified mechanisms responsible for increased complexity, convergence, evolvability, and more. Our goal is to extract concepts across studies that can be generalized to serve as applicable frameworks for future research efforts. Participants will receive an optional reading list and are encouraged to read papers that appeal to them, however the relevant background for each paper and crucial results will be presented by the instructor in each session. This course offers an approachable format, as time will be allotted throughout each session for questions and discussion.

Course Schedule
Session I (Jul. 29) - General Introduction & Convergence: Convergent evolution in diving Anolis lizards & Repeated transitions towards high-altitude climates in Andean hummingbirds
Session II (July 31) - Contingency: Evolution of plant toxin resistance in monarch butterflies & Functional novelty in vertebrate hormone receptors
Session III (Aug. 5) - Evolvability: How prior selection and chance can enhance future evolutionary potential in bacteria
Session IV (Aug. 7) - Complexity: Building irreducible machines in fungi and photosynthetic organisms

Reading List

1. Boccia, C. K. et al. Repeated evolution of underwater rebreathing in diving Anolis lizards. Curr. Biol. (2021): doi.org/10.1016/j.cub.2021.04.040
2. Projecto-Garcia, J. et al. Repeated elevational transitions in hemoglobin function during the evolution of Andean hummingbirds. Proc. Natl. Acad. Sci. (2013): doi.org/10.1073/pnas.1315456110
3. Karageorgi, M. et al. Genome editing retraces the evolution of toxin resistance in the monarch butterfly. Nature (2019): doi.org/10.1038/s41586-019-1610-8
4. Ortlund, E. A., Bridgham, J. T., Redinbo, M. R. & Thornton, J. W. Crystal structure of an ancient protein: Evolution by conformational epistasis. Science (2007): doi.org/10.1126/science.1142819
5. Zheng, J., Guo, N. & Wagner, A. Selection enhances protein evolvability by increasing mutational robustness and foldability. Science (2020): doi.org/10.1126/science.abb5962
6. Barnett, M., Meister, L. & Rainey, P. B. Experimental evolution of evolvability. Science (2025): doi.org/10.1126/science.adr2756
7. Finnigan, G. C., Hanson-Smith, V., Stevens, T. H. & Thornton, J. W. Evolution of increased complexity in a molecular machine. Nature (2012): doi.org/10.1038/nature10724
8. Schulz, L. et al. Evolution of increased complexity and specificity at the dawn of form I Rubiscos. Science (2022): https://doi.org/10.1126/science.abq1416