A researcher at the University of Michigan has been studying the generations of Escherichia coli for 20 years. In total, it has researched 40,000 generations and, among them, has frozen some copies to preserve a photograph of specific moments of the process. The research has been published in the scientific journal PNAS and one of the conclusions is that some random steps are taken in the evolutionary process. Research helps clarify whether evolution is deterministic or random.