The Digital Life Laboratory at the California Institute of Technology is a research group focusing on the dynamics of simple living systems, in particular their evolution. Fundamentally, this research is guided by the premise that the physical processes that give rise to life can be characterized by a set of simple principles, and that these principles can be implemented in different media as long as the latter allow for enough complexity. According to this view, simple living systems can be constructed. We have developed a computational system, the Avida software, which can be used to study certain basic properties of simple living systems, namely those that do not depend on the particular embodiment of information storage and machinery. Avida creates an environment within any standard computer in which populations of computer programs can live, evolve, and adapt. These programs can be thought of as a form of domesticated computer viruses, but they undergo mutations and after a few hundred generations look nothing like the ancestor from whom they were spawned. They evolve, adapt, and grow in complexity. As such they appear to represent an independent form of life that does not share any ancestry with life on Earth.

We use 'avidians' as a model organism for experimental evolution. While the genome of standard avidians is much shorter than that of the simplest bacteria, their evolutionary dynamics is quite similar. In collaboration with the Digital Evolution Group at Michigan State University (led by Charles Ofria and Richard Lenski), we are testing evolutionary hypotheses and study their universality across different forms of life. At the same time, we are developing new hypotheses based on data obtained both with biochemical, and digital organisms.