Beagle in a flask: Adaptive laboratory evolution of ancient proteins in bacteria
Our living world is the result of a complex history spanning billions of years. Scientists have access to artifacts of this history, namely the fossil record and the genomes of many different living organisms. But there are surprisingly limited means with which to infer the exact evolutionary history that resulted in modern biota. It is difficult to reconcile fossil morphology on the one hand, and genetic composition and diversification over time on the other, when so little about the biological behavior of ancestral organisms can be reconstructed to link these data. This limitation makes it difficult to approach intriguing questions of whether the evolutionary paths that produced modern organisms were highly deterministic (i.e., life as a factory) or inherently dominated by chance (i.e., life as a casino parlor). Did life in the past function or evolve similarly to life today? Did the biology of ancestral organisms, the functions of their proteins or other factors inherently limit their ability to evolve into modern forms? To attempt to overcome these historical limitations, we resurrected 1.3 to 3.6 billion year old genes inside modern E. coli microbes. By engineering revenant proteins inside modern organisms, we can characterize their biological function and observe the holistic effects that they have on the cell’s behavior.