Jeffrey Todd Streelman Georgia Institute of Technology
Understanding complexity is a central goal of science. Advances in computation, physics, biology and engineering have engendered a set of design principles that characterize complex systems. Theoretically, systems as varied as the Internet, tropical rainforests, and the proteins within a cell are similarly organized. It has been suggested that complexity is an emergent property of these design principles and that highly complex systems are qualitatively different from simple ones. The distinction between complex and simple systems has been illustrated using biomechanical models that predict force and motion (or kinematic transmission, KT) in the oral jaws of bony fishes. Simple lever models of the lower jaw exhibit a one-to-one relationship between form and function; proportional differences in the lengths of component bones produce proportional differences in KT. By contrast, more complex models of anterior jaw mechanics (called 4-bar linkage systems) show a nonlinear, many-to-one mapping of form to function; multiply shaped 4-bar configurations yield the same KT. Knowledge of how form maps to function is a first step to understand how simple and complex biomechanical systems evolve, yet we know almost nothing about the genetic basis of these systems. This research plan fuses biomechanics and evolutionary genomics in cichlid fishes from Lake Malawi, East Africa to ask how complexity is wired into genomes and whether complex systems have genetic architectures that differ from simpler systems. Research involves post-docs, graduate students, undergraduates (in Biology and Engineering) and high school fellows. The education plan integrates research and teaching around the mechanics of cichlid jaws to foster far-reaching impact outside of the principal investigator's lab. This project will facilitate hands-on learning in math and science among public high school students and teachers from the city of Atlanta, and the general public through interactive exhibits at the Georgia Aquarium.
Over the final project period (02/2012 - 01/2013), Streelman's group published two papers in the journals Haredity and Evolution contributing to the main goal of this project -- namely to understand the genetics and evolution of simple versus complex biomechanical systems. These two papers (i) describe pioneering ways to construct genetic maps in evolutionary model species and (ii) pinpoint the genetic basis of functional systems exhibiting 'many-to-one-mapping.' Broadly, 'many-to-one-mapping' is a general theme uniting complex system research in physiology, biomechanics, evolution and engineering. Finally, Streelman's group established connections with Atlanta area elementary schools to provide expert lectures via high-speed internet and video conferencing. This program will continue past the award's expiration, and serves as a platform for further interaction between faculty at Georgia Tech and students in Atlanta Public Schools. Over the entire project period, this award resulted in: -- a springboard for Streelman's early faculty career (tenure in 2009) -- over 15 scientific publications -- training of undergraduate students who have entered graduate school in science in the US and UK -- training of graduate students, who have attained postdocs in Science in the US and France -- training of postdocs, who have since attained (or plan to attain) faculty positions in the US.
